Search

Background BNT162b2 is a lipid nanoparticle–formulated, nucleoside-modified RNA vaccine encoding a prefusion-stabilized, membrane-anchored severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) full-length spike protein. BNT162b2 is highly efficacious against coronavirus disease 2019 (Covid-19) and is currently approved, conditionally approved, or authorized for emergency use worldwide. At the time of initial authorization, data beyond 2 months after vaccination were unavailable. Methods In an ongoing, placebo-controlled, observer-blinded, multinational, pivotal efficacy trial, we randomly assigned 44,165 participants 16 years of age or older and 2264 participants 12 to 15 years of age to receive two 30-μg doses, at 21 days apart, of BNT162b2 or placebo. The trial end points were vaccine efficacy against laboratory-confirmed Covid-19 and safety, which were both evaluated through 6 months after vaccination. Results BNT162b2 continued to be safe and have an acceptable adverse-event profile. Few participants had adverse events leading to withdrawal from the trial. Vaccine efficacy against Covid-19 was 91.3% (95% confidence interval [CI], 89.0 to 93.2) through 6 months of follow-up among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated. There was a gradual decline in vaccine efficacy. Vaccine efficacy of 86 to 100% was seen across countries and in populations with diverse ages, sexes, race or ethnic groups, and risk factors for Covid-19 among participants without evidence of previous infection with SARS-CoV-2. Vaccine efficacy against severe disease was 96.7% (95% CI, 80.3 to 99.9). In South Africa, where the SARS-CoV-2 variant of concern B.1.351 (or beta) was predominant, a vaccine efficacy of 100% (95% CI, 53.5 to 100) was observed. Conclusions Through 6 months of follow-up and despite a gradual decline in vaccine efficacy, BNT162b2 had a favorable safety profile and was highly efficacious in preventing Covid-19. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.)

In March 2020, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)1, a pandemic. With rapidly accumulating numbers of cases and deaths reported globally2, a vaccine is urgently needed. Here we report the available safety, tolerability and immunogenicity data from an ongoing placebo-controlled, observer-blinded dose-escalation study (ClinicalTrials.gov identifier NCT04368728) among 45 healthy adults (18–55 years of age), who were randomized to receive 2 doses—separated by 21 days—of 10 μg, 30 μg or 100 μg of BNT162b1. BNT162b1 is a lipid-nanoparticle-formulated, nucleoside-modified mRNA vaccine that encodes the trimerized receptor-binding domain (RBD) of the spike glycoprotein of SARS-CoV-2. Local reactions and systemic events were dose-dependent, generally mild to moderate, and transient. A second vaccination with 100 μg was not administered because of the increased reactogenicity and a lack of meaningfully increased immunogenicity after a single dose compared with the 30-μg dose. RBD-binding IgG concentrations and SARS-CoV-2 neutralizing titres in sera increased with dose level and after a second dose. Geometric mean neutralizing titres reached 1.9–4.6-fold that of a panel of COVID-19 convalescent human sera, which were obtained at least 14 days after a positive SARS-CoV-2 PCR. These results support further evaluation of this mRNA vaccine candidate. In a dose-escalation study of the COVID-19 RNA vaccine BNT162b1 in 45 healthy adults, RBD-binding IgG concentrations and SARS-CoV-2 neutralizing titres in sera increased with dose level and after a second vaccine dose.

BACKGROUND Clinical trials for antibiotics designed to treat hospital-acquired and ventilator-associated bacterial pneumonias (HABP/VABP) are hampered by making these diagnoses in a way that is acceptable to the United States Food and Drug Administration and consistent with standards of care. We examined laboratory and clinical features that might improve pediatric HABP/VABP trial efficiency by identifying risk factors predisposing children to HABP/VABP and describing the epidemiology of pediatric HABP/VABP. METHODS We prospectively reviewed the electronic medical records of patients

The Shigella controlled human infection model (CHIM) is valuable for assessing candidate Shigella vaccine efficacy and potentially accelerating regulatory approval. The Shigella CHIM is currently being conducted at 3 sites in the United States using Shigella flexneri 2a strain 2457T and Shigella sonnei strain 53G. Shigellosis can present variably as watery diarrhea alone or with dysentery, and can be accompanied by manifestations including fever, abdominal cramps, tenesmus, and malaise. For comparability, it is important to harmonize the primary clinical endpoint. An expert working group was convened on 2 February 2018 to review clinical data from Shigella CHIM studies performed to date and to develop a consensus primary endpoint. The consensus endpoint enabled “shigellosis” to present as severe diarrhea or moderate diarrhea or dysentery. The latter 2 criteria are met when concurrent with fever of 38.0°C and/or vomiting, and/or a constitutional/enteric symptom graded at least as “moderate” severity. The use of a blinded independent committee to adjudicate the primary endpoint by subject was also regarded as important. As safety of volunteers in challenge studies is of paramount importance and treatment timing can affect primary outcomes, a standard for early antibiotic administration was established as follows: (1) when the primary endpoint is met; (2) if a fever of ≥39.0°C develops; or (3) if the study physician deems it appropriate. Otherwise, antibiotics are given at 120 hours postinfectious challenge. The working group agreed on objective and subjective symptoms to be solicited, and standardized methods for assessing subject-reported severity of symptoms.

The use of the controlled human infection model to facilitate product development and to advance understanding of host-pathogen interactions is of increasing interest. While administering a virulent (or infective) organism to a susceptible host necessitates an ongoing evaluation of safety and ethical considerations, a central theme in conducting these studies in a safe and ethical manner that yields actionable data is their conduct in facilities well-suited to address their unique attributes. To that end, we have developed a framework for evaluating potential sites in which to conduct inpatient enteric controlled human infection model to ensure consistency and increase the likelihood of success.

Background Safe, effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in children younger than 12 years of age. Methods A phase 1, dose-finding study and an ongoing phase 2-3 randomized trial are being conducted to investigate the safety, immunogenicity, and efficacy of two doses of the BNT162b2 vaccine administered 21 days apart in children 6 months to 11 years of age. We present results for 5-to-11-year-old children. In the phase 2-3 trial, participants were randomly assigned in a 2:1 ratio to receive two doses of either the BNT162b2 vaccine at the dose level identified during the open-label phase 1 study or placebo. Immune responses 1 month after the second dose of BNT162b2 were immunologically bridged to those in 16-to-25-year-olds from the pivotal trial of two 30-μg doses of BNT162b2. Vaccine efficacy against Covid-19 at 7 days or more after the second dose was assessed. Results During the phase 1 study, a total of 48 children 5 to 11 years of age received 10 μg, 20 μg, or 30 μg of the BNT162b2 vaccine (16 children at each dose level). On the basis of reactogenicity and immunogenicity, a dose level of 10 μg was selected for further study. In the phase 2-3 trial, a total of 2268 children were randomly assigned to receive the BNT162b2 vaccine (1517 children) or placebo (751 children). At data cutoff, the median follow-up was 2.3 months. In the 5-to-11-year-olds, as in other age groups, the BNT162b2 vaccine had a favorable safety profile. No vaccine-related serious adverse events were noted. One month after the second dose, the geometric mean ratio of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing titers in 5-to-11-year-olds to those in 16-to-25-year-olds was 1.04 (95% confidence interval [CI], 0.93 to 1.18), a ratio meeting the prespecified immunogenicity success criterion (lower bound of two-sided 95% CI, >0.67; geometric mean ratio point estimate, ≥0.8). Covid-19 with onset 7 days or more after the second dose was reported in three recipients of the BNT162b2 vaccine and in 16 placebo recipients (vaccine efficacy, 90.7%; 95% CI, 67.7 to 98.3). Conclusions A Covid-19 vaccination regimen consisting of two 10-μg doses of BNT162b2 administered 21 days apart was found to be safe, immunogenic, and efficacious in children 5 to 11 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

BackgroundWhile Coronavirus disease 2019 (Covid-19) vaccines are highly effective, breakthrough infections are occurring. Booster vaccinations have recently received emergency use authorization (EUA) for certain populations but are restricted to homologous mRNA vaccines. We evaluated homologous and heterologous booster vaccination in persons who had received an EUA Covid-19 vaccine regimen.MethodsIn this phase 1/2 open-label clinical trial conducted at ten U.S. sites, adults who received one of three EUA Covid-19 vaccines at least 12 weeks prior to enrollment and had no reported history of SARS-CoV-2 infection received a booster injection with one of three vaccines (Moderna mRNA-1273 100-μg, Janssen Ad26.COV2.S 5×1010 virus particles, or Pfizer-BioNTech BNT162b2 30-μg; nine combinations). The primary outcomes were safety, reactogenicity, and humoral immunogenicity on study days 15 and 29.Results458 individuals were enrolled: 154 received mRNA-1273, 150 received Ad26.CoV2.S, and 153 received BNT162b2 booster vaccines. Reactogenicity was similar to that reported for the primary series. Injection site pain, malaise, headache, and myalgia occurred in more than half the participants. Booster vaccines increased the neutralizing activity against a D614G pseudovirus (4.2-76-fold) and binding antibody titers (4.6-56-fold) for all combinations; homologous boost increased neutralizing antibody titers 4.2-20-fold whereas heterologous boost increased titers 6.2-76-fold. Day 15 neutralizing and binding antibody titers varied by 28.7-fold and 20.9-fold, respectively, across the nine prime-boost combinations.ConclusionHomologous and heterologous booster vaccinations were well-tolerated and immunogenic in adults who completed a primary Covid-19 vaccine regimen at least 12 weeks earlier.(Funded by National Institute of Allergy and Infectious Diseases; Clinical Trials.gov number, NCT04889209)

Immune Response to a Third Dose of BNT162b2 A third dose of the BNT162b2 vaccine was administered to 23 volunteers 8 to 9 months after the second dose, and the immune response was assessed. Local r...

Shigella spp. are a leading cause of diarrhea-associated global morbidity and mortality. Development and widespread implementation of an efficacious vaccine remain the best option to reduce Shigella-specific morbidity. Unfortunately, the lack of a well-defined correlate of protection for shigellosis continues to hinder vaccine development efforts. Shigella controlled human infection models (CHIM) are often used in the early stages of vaccine development to provide preliminary estimates of vaccine efficacy; however, CHIMs also provide the opportunity to conduct in-depth immune response characterizations pre- and postvaccination or pre- and postinfection. In the current study, principal-component analyses were used to examine immune response data from two recent Shigella CHIMs in order to characterize immune response profiles associated with parenteral immunization, oral challenge with Shigella flexneri 2a, or oral challenge with Shigella sonnei. Although parenteral immunization induced an immune profile characterized by robust systemic antibody responses, it also included mucosal responses. Interestingly, oral challenge with S. flexneri 2a induced a distinctively different profile compared to S. sonnei, characterized by a relatively balanced systemic and mucosal response. In contrast, S. sonnei induced robust increases in mucosal antibodies with no differences in systemic responses across shigellosis outcomes postchallenge. Furthermore, S. flexneri 2a challenge induced significantly higher levels of intestinal inflammation compared to S. sonnei, suggesting that both serotypes may also differ in how they trigger induction and activation of innate immunity. These findings could have important implications for Shigella vaccine development as protective immune mechanisms may differ across Shigella serotypes. IMPORTANCE Although immune correlates of protection have yet to be defined for shigellosis, prior studies have demonstrated that Shigella infection provides protection against reinfection in a serotype-specific manner. Therefore, it is likely that subjects with moderate to severe disease post-oral challenge would be protected from a homologous rechallenge, and investigating immune responses in these subjects may help identify immune markers associated with the development of protective immunity. This is the first study to describe distinct innate and adaptive immune profiles post-oral challenge with two different Shigella serotypes. Analyses conducted here provide essential insights into the potential of different immune mechanisms required to elicit protective immunity, depending on the Shigella serotype. Such differences could have significant impacts on vaccine design and development within the Shigella field and should be further investigated across multiple Shigella serotypes.

BackgroundBNT162b2 is a lipid nanoparticle-formulated, nucleoside-modified RNA vaccine encoding a prefusion-stabilized, membrane-anchored SARS-CoV-2 full-length spike protein. BNT162b2 is highly efficacious against COVID-19 and is currently authorized for emergency use or conditional approval worldwide. At the time of authorization, data beyond 2 months post-vaccination were unavailable.MethodsIn an ongoing, placebo-controlled, observer-blinded, multinational, pivotal efficacy study, 44,165 ≥16-year-old participants and 2,264 12-15-year-old participants were randomized to receive 2 doses, 21 days apart, of 30 µg BNT162b2 or placebo. Study endpoints reported here are vaccine efficacy (VE) against laboratory-confirmed COVID-19 and safety data, both up to 6 months post-vaccination.ResultsBNT162b2 continued to be safe and well tolerated. Few participants had adverse events leading to study withdrawal. VE against COVID-19 was 91% (95% CI 89.0-93.2) through up to 6 months of follow-up, among evaluable participants and irrespective of previous SARS-CoV-2 infection. VE of 86%-100% was seen across countries and in populations with diverse characteristics of age, sex, race/ethnicity, and COVID-19 risk factors in participants without evidence of previous SARS-CoV-2 infection. VE against severe disease was 97% (95% CI 80.3−99.9). In South Africa, where the SARS-CoV-2 variant of concern, B.1.351 (beta), was predominant, 100% (95% CI 53.5, 100.0) VE was observed.ConclusionWith up to 6 months of follow-up and despite a gradually declining trend in vaccine efficacy, BNT162b2 had a favorable safety profile and was highly efficacious in preventing COVID-19. (ClinicalTrials.govnumber,NCT04368728)

Background Until very recently, vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had not been authorized for emergency use in persons younger than 16 years of age. Safe, effective vaccines are needed to protect this population, facilitate in-person learning and socialization, and contribute to herd immunity. Methods In this ongoing multinational, placebo-controlled, observer-blinded trial, we randomly assigned participants in a 1:1 ratio to receive two injections, 21 days apart, of 30 μg of BNT162b2 or placebo. Noninferiority of the immune response to BNT162b2 in 12-to-15-year-old participants as compared with that in 16-to-25-year-old participants was an immunogenicity objective. Safety (reactogenicity and adverse events) and efficacy against confirmed coronavirus disease 2019 (Covid-19; onset, ≥7 days after dose 2) in the 12-to-15-year-old cohort were assessed. Results Overall, 2260 adolescents 12 to 15 years of age received injections; 1131 received BNT162b2, and 1129 received placebo. As has been found in other age groups, BNT162b2 had a favorable safety and side-effect profile, with mainly transient mild-to-moderate reactogenicity (predominantly injection-site pain [in 79 to 86% of participants], fatigue [in 60 to 66%], and headache [in 55 to 65%]); there were no vaccine-related serious adverse events and few overall severe adverse events. The geometric mean ratio of SARS-CoV-2 50% neutralizing titers after dose 2 in 12-to-15-year-old participants relative to 16-to-25-year-old participants was 1.76 (95% confidence interval [CI], 1.47 to 2.10), which met the noninferiority criterion of a lower boundary of the two-sided 95% confidence interval greater than 0.67 and indicated a greater response in the 12-to-15-year-old cohort. Among participants without evidence of previous SARS-CoV-2 infection, no Covid-19 cases with an onset of 7 or more days after dose 2 were noted among BNT162b2 recipients, and 16 cases occurred among placebo recipients. The observed vaccine efficacy was 100% (95% CI, 75.3 to 100). Conclusions The BNT162b2 vaccine in 12-to-15-year-old recipients had a favorable safety profile, produced a greater immune response than in young adults, and was highly effective against Covid-19. (Funded by BioNTech and Pfizer; C4591001 ClinicalTrials.gov number, NCT04368728.)

Background: Shigellosis accounts for substantial morbidity and mortality worldwide and is the second most common cause of moderate and severe diarrhoea in children, after rotavirus. Methods: This phase 2b study (NCT03527173) evaluated vaccine efficacy (VE) against shigellosis, safety, and immunogenicity of a Shigella sonnei GMMA candidate vaccine (1790GAHB) in adults, using a S. sonnei 53G controlled human infection model (CHIM). Participants (randomized 1:1) received two doses of 1790GAHB or placebo (GAHB-Placebo), at day (D) 1 and D29, and an oral challenge of S. sonnei 53G at D57. VE was evaluated using several clinical endpoints, reflecting different case definitions of shigellosis. The success criterion was defined as a lower limit of the 90% confidence interval >0 for the primary endpoint. Findings: Thirty-six and 35 participants received 1790GAHB or placebo, respectively; 33 and 29 received the bacterial challenge, 15 and 12 participants developed shigellosis. Efficacy was not demonstrated for any endpoint. Solicited/unsolicited adverse events were more frequent in 1790GAHB versus placebo recipients post-vaccination. Anti-S. sonnei lipopolysaccharide (LPS) immunoglobulin G (IgG) responses increased at D29 and remained stable through D57 in the 1790GAHB group; no increase was shown in the placebo group. Interpretation: 1790GAHB had an acceptable safety profile and induced anti-LPS IgG responses but did not demonstrate clinical efficacy against shigellosis. Baseline and pre-challenge antibody levels were higher in participants who did not develop shigellosis post-challenge, thus suggesting a role of anti-LPS IgG antibodies in clinical protection. Although a precise threshold for clinical protection remains unknown, antibody levels derived from convalescent sera have demonstrated protection from shigellosis in field studies; however, this concept did not translate to the current CHIM. For further development of the vaccine, an increased content of S. sonnei O-antigen is likely needed to enhance anti-LPS immune responses. Trial Registration: NCT03527173 Funding Statement: GlaxoSmithKline Biologicals SA, the Bill and Melinda Gates Foundation. Declaration of Interests: AP, LBM, RR, GLC, PF, IDR, FM, FN, EM, JA, AA, OR and VC are employees of the GSK group of companies. AP, LBM, EM, and JA hold shares in the GSK group of companies. JA, LBM, AS, GLC, AGWN, PF, and IDR report grants from the Bill and Melinda Gates Foundation and the Wellcome Trust during the conduct of the study. LBM reports grants from the Bill and Melinda Gates foundation and the Wellcome Trust, outside the submitted work. AS, AGWN, and JPG were employees of the GSK group of companies at the time of study conduct. AA report personal fees from GSK Vaccines Institute for Global Health during the conduct of the study. AS hold shares in the GSK group of companies. LBM and AS are inventors of patents owned by the GSK group of companies and relevant to Shigella vaccine. AES, KAC, LC, MMcN, and RWK report grants from the GSK group of companies during the conduct of the trial. MMcN reports grants from NIH, outside the submitted work. MD, SP, and RWF have nothing to disclose. Ethics Approval Statement: The study was conducted in accordance with all applicable regulatory requirements, International Conference on Harmonisation - Good Clinical Practice guidelines, and the Declaration of Helsinki. The protocol and study-related documents were reviewed and approved by the institutional review board at the site. All participants provided electronic consent through REDcap system (www.projectredcap.org), except for one who provided written consent because the REDcap system was not working.

The levels of antigen-specific Antibodies in Lymphocyte Supernatant (ALS) using an ELISA are being used to evaluate mucosal immune responses as an alternate to measuring the number of Antibody Secreting Cells (ASCs) using an ELISpot assay. A recently completed trial of two novel S. sonnei live oral vaccine candidates WRSs2 and WRSs3 established that both candidates were safe, well tolerated and immunogenic in a vaccine dose-dependent manner. Previously, mucosal immune responses were measured by assaying IgA- and IgG-ASC in peripheral blood mononuclear cells (PBMCs). In this report, the magnitude of the S. sonnei antigen-specific IgA- and IgG-ALS responses was measured and correlated with previously described ASCs, serum antibodies, fecal IgA and vaccine shedding. Overall, the magnitude of S. sonnei anti-Invaplex50 ALS was higher than that of LPS or IpaB, and both vaccines demonstrated a more robust IgA-ALS response than IgG; however, compared to WRSs3, the magnitude and percentage of responders were higher among WRSs2 recipients for IgA- or IgG-ALS. All WRSs2 vaccinees at the two highest doses responded for LPS and Invaplex50-specific IgA-ALS and 63–100% for WRSs3 vaccinees responded. Regardless of the vaccine candidate, vaccine dose or detecting antigen, the kinetics of ALS responses were similar peaking on days 7 to 9 and returning to baseline by day 14. The ALS responses were vaccine-specific since no responses were detected among placebo recipients at any time. A strong correlation and agreement between responders/non-responders were noted between ALS and other mucosal (ASC and fecal IgA) and systemic (serum antibody) immune responses. These data indicate that the ALS assay can be a useful tool to evaluate mucosal responses to oral vaccination, an observation noted with trials of other bacterial diarrheal pathogens. Furthermore, this data will guide the list of immunological assays to be conducted for efficacy trials in different populations. It is hoped that an antigen-specific-ALS titer may be a key mucosal correlate of protection, a feature not currently available for any Shigella vaccines candidates. https://clinicaltrials.gov/show/NCT01336699.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (Covid-19) have afflicted tens of millions of people in a worldwide pandemic. Safe and effective vaccines are needed urgently.In an ongoing multinational, placebo-controlled, observer-blinded, pivotal efficacy trial, we randomly assigned persons 16 years of age or older in a 1:1 ratio to receive two doses, 21 days apart, of either placebo or the BNT162b2 vaccine candidate (30 μg per dose). BNT162b2 is a lipid nanoparticle-formulated, nucleoside-modified RNA vaccine that encodes a prefusion stabilized, membrane-anchored SARS-CoV-2 full-length spike protein. The primary end points were efficacy of the vaccine against laboratory-confirmed Covid-19 and safety.A total of 43,548 participants underwent randomization, of whom 43,448 received injections: 21,720 with BNT162b2 and 21,728 with placebo. There were 8 cases of Covid-19 with onset at least 7 days after the second dose among participants assigned to receive BNT162b2 and 162 cases among those assigned to placebo; BNT162b2 was 95% effective in preventing Covid-19 (95% credible interval, 90.3 to 97.6). Similar vaccine efficacy (generally 90 to 100%) was observed across subgroups defined by age, sex, race, ethnicity, baseline body-mass index, and the presence of coexisting conditions. Among 10 cases of severe Covid-19 with onset after the first dose, 9 occurred in placebo recipients and 1 in a BNT162b2 recipient. The safety profile of BNT162b2 was characterized by short-term, mild-to-moderate pain at the injection site, fatigue, and headache. The incidence of serious adverse events was low and was similar in the vaccine and placebo groups.A two-dose regimen of BNT162b2 conferred 95% protection against Covid-19 in persons 16 years of age or older. Safety over a median of 2 months was similar to that of other viral vaccines. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.).

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the resulting disease, coronavirus disease 2019 (Covid-19), have spread to millions of persons worldwide. Multiple vaccine candidates are under development, but no vaccine is currently available. Interim safety and immunogenicity data about the vaccine candidate BNT162b1 in younger adults have been reported previously from trials in Germany and the United States. Methods In an ongoing, placebo-controlled, observer-blinded, dose-escalation, phase 1 trial conducted in the United States, we randomly assigned healthy adults 18 to 55 years of age and those 65 to 85 years of age to receive either placebo or one of two lipid nanoparticle–formulated, nucleoside-modified RNA vaccine candidates: BNT162b1, which encodes a secreted trimerized SARS-CoV-2 receptor–binding domain; or BNT162b2, which encodes a membrane-anchored SARS-CoV-2 full-length spike, stabilized in the prefusion conformation. The primary outcome was safety (e.g., local and systemic reactions and adverse events); immunogenicity was a secondary outcome. Trial groups were defined according to vaccine candidate, age of the participants, and vaccine dose level (10 μg, 20 μg, 30 μg, and 100 μg). In all groups but one, participants received two doses, with a 21-day interval between doses; in one group (100 μg of BNT162b1), participants received one dose. Results A total of 195 participants underwent randomization. In each of 13 groups of 15 participants, 12 participants received vaccine and 3 received placebo. BNT162b2 was associated with a lower incidence and severity of systemic reactions than BNT162b1, particularly in older adults. In both younger and older adults, the two vaccine candidates elicited similar dose-dependent SARS-CoV-2–neutralizing geometric mean titers, which were similar to or higher than the geometric mean titer of a panel of SARS-CoV-2 convalescent serum samples. Conclusions The safety and immunogenicity data from this U.S. phase 1 trial of two vaccine candidates in younger and older adults, added to earlier interim safety and immunogenicity data regarding BNT162b1 in younger adults from trials in Germany and the United States, support the selection of BNT162b2 for advancement to a pivotal phase 2–3 safety and efficacy evaluation. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04368728.)

Controlled human infection models (CHIMs) are invaluable tools utilized to understand the human response to infection, potentially leading to protective immune mechanisms and allowing efficacy testing of enteric countermeasures, including vaccines, antibiotics, and other products. The development of an improved Shigella CHIM for both Shigella sonnei and Shigella flexneri is consistent with international efforts, supported by international donors and the World Health Organization, focused on standardizing Shigella CHIMs and using them to accelerate Shigella vaccine development. The use of lyophilized Shigella challenge strains rather than plate-grown inoculum preparations is considered an important step forward in the standardization process. Furthermore, the results of studies such as this justify the development of lyophilized preparations for additional epidemiologically important S. flexneri serotypes, including S. flexneri 3a and S. flexneri 6., Controlled human infection models (CHIMs) are useful for vaccine development. To improve on existing models, we developed a CHIM using a lyophilized preparation of Shigella sonnei strain 53G produced using current good manufacturing practice (cGMP). Healthy adults were enrolled in an open-label dose-ranging study. Following administration of a dose of rehydrated S. sonnei strain 53G, subjects were monitored for development of disease. The first cohort received 500 CFU of 53G, and dosing of subsequent cohorts was based on results from the previous cohort. Subjects were administered ciprofloxacin on day 5 and discharged home on day 8. Subjects returned as outpatients for clinical checks and sample collection. Attack rates increased as the dose of S. sonnei was increased. Among those receiving the highest dose (1,760 CFU), 70% developed moderate to severe diarrhea, 50% had dysentery, and 40% had fever. Antilipopolysaccharide responses were observed across all cohorts. An S. sonnei CHIM using a lyophilized lot of strain 53G was established. A dose in the range of 1,500 to 2,000 CFU of 53G was selected as the dose for future challenge studies using this product. This model will enable direct comparison of study results between institutions and ensure better consistency over time in the challenge inoculum. IMPORTANCE Controlled human infection models (CHIMs) are invaluable tools utilized to understand the human response to infection, potentially leading to protective immune mechanisms and allowing efficacy testing of enteric countermeasures, including vaccines, antibiotics, and other products. The development of an improved Shigella CHIM for both Shigella sonnei and Shigella flexneri is consistent with international efforts, supported by international donors and the World Health Organization, focused on standardizing Shigella CHIMs and using them to accelerate Shigella vaccine development. The use of lyophilized Shigella challenge strains rather than plate-grown inoculum preparations is considered an important step forward in the standardization process. Furthermore, the results of studies such as this justify the development of lyophilized preparations for additional epidemiologically important S. flexneri serotypes, including S. flexneri 3a and S. flexneri 6.

Correlate(s) of immunity have yet to be defined for shigellosis. As previous disease protects against subsequent infection in a serotype-specific manner, investigating immune response profiles pre- and postinfection provides an opportunity to identify immune markers potentially associated with the development of protective immunity and/or with a reduced risk of developing shigellosis postchallenge. This study is the first to report such an extensive characterization of the immune response after challenge with S. sonnei 53G. Results demonstrate an association of progression to shigellosis with robust intestinal inflammatory and mucosal gut-homing responses. An important finding in this study was the association of elevated Shigella LPS-specific serum IgA and memory B cell IgA responses at baseline with reduced risk of disease. The increased baseline IgA responses may contribute to the lack of dose response observed in the study and suggests that IgA responses should be further investigated as potential correlates of immunity., Shigella is a major cause of moderate to severe diarrhea largely affecting children (

While adult clinical trials of coronavirus disease 2019 (COVID-19) vaccines have moved quickly into phase 3 clinical trials, clinical trials have not started in children in the United States. The direct COVID-19 impact upon children is greater than that observed for a number of other pathogens for which we now have effective pediatric vaccines. Additionally, the role of children in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has clearly been underappreciated. Carefully conducted phase 2 clinical trials can adequately address potential COVID-19 vaccine safety concerns. Delaying phase 2 vaccine clinical trials in children will delay our recovery from COVID-19 and unnecessarily prolong its impact upon children’s education, health, and emotional well-being, and equitable access to opportunities for development and social success. Given the potential direct and indirect benefits of pediatric vaccination, implementation of phase 2 clinical trials for COVID-19 vaccines should begin now.

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the resulting disease, coronavirus disease 2019 (COVID-19), have spread to millions of people globally. Multiple vaccine candidates are under development, but no vaccine is currently available.MethodsHealthy adults 18–55 and 65–85 years of age were randomized in an ongoing, placebo-controlled, observer-blinded dose-escalation study to receive 2 doses at 21-day intervals of placebo or either of 2 lipid nanoparticle–formulated, nucleoside-modified RNA vaccine candidates: BNT162b1, which encodes a secreted trimerized SARS-CoV-2 receptor-binding domain, or BNT162b2, which encodes a prefusion stabilized membrane-anchored SARS-CoV-2 full-length spike. In each of 13 groups of 15 participants, 12 received vaccine and 3 received placebo. Groups were distinguished by vaccine candidate, age of participant, and vaccine dose level. Interim safety and immunogenicity data of BNT162b1 in younger adults have been reported previously from US and German trials. We now present additional safety and immunogenicity data from the US Phase 1 trial that supported selection of the vaccine candidate advanced to a pivotal Phase 2/3 safety and efficacy evaluation.ResultsIn both younger and older adults, the 2 vaccine candidates elicited similar dose- dependent SARS-CoV-2-neutralizing geometric mean titers (GMTs), comparable to or higher than the GMT of a panel of SARS-CoV-2 convalescent sera. BNT162b2 was associated with less systemic reactogenicity, particularly in older adults.ConclusionThese results support selection of the BNT162b2 vaccine candidate for Phase 2/3 large-scale safety and efficacy evaluation, currently underway.

Background Staphylococcus aureus causes serious health care– and community-associated disease, requiring improved preventive measures such as vaccines. The investigational S. aureus 4-antigen vaccine (SA4Ag), comprising capsular polysaccharide serotypes 5 and 8 (CP5 and CP8) conjugated to CRM197, recombinant mutant clumping factor A (rmClfA), and recombinant manganese transporter protein C (rP305A or rMntC), was well tolerated, inducing robust functional immune responses to all 4 antigens through 12 months postvaccination. This is a serological extension study through 36 months postvaccination. Methods In 2 previous studies, healthy adults received SA4Ag, SA3Ag (without rMntC), or placebo; serology was also assessed at ~24 and ~36 months postvaccination. Functional immune responses (antibody responses that facilitate killing of S. aureus or neutralize S. aureus virulence mechanisms) were assessed with opsonophagocytic activity killing assays (CP5 or CP8) and a fibrinogen-binding inhibition assay (ClfA). A competitive Luminex immunoassay assessed ClfA and rMntC responses. Adverse events within 48 hours of blood draw were recorded. Results Four hundred forty subjects (18–64 years old, 255; 65–85 years old, 185) were enrolled. At 24 and 36 months postvaccination, subjects receiving SA4Ag had substantially higher geometric mean titers (GMTs) for CP5, CP8, and ClfA vs baseline; geometric mean fold rises (GMFRs) from baseline to month 36 were 2.7–8.1. For rMntC, 36-month GMTs declined from peak levels but remained above baseline for all SA4Ag groups; GMFRs from baseline to month 36 were 1.8 and 1.5 in the younger and older cohorts, respectively. Conclusions Persistent functional immune responses to S. aureus antigens were observed through 36 months in healthy adults. ClinicalTrials.gov NCT01643941 and NCT01364571.

We describe the successful treatment of a 10-month-old female with respiratory distress secondary to Coronavirus disease 2019 (COVID-19) with the nebulized investigational drug, DAS181. Therapy was well tolerated, and the patient had minimal side effects. The patient's respiratory distress and positive viral polymerase chain reaction rapidly resolved after initiation of therapy.

Background Shigellosis accounts for substantial morbidity and mortality worldwide and is the second most common cause of moderate and severe diarrhoea in children. Methods This phase 2b study (NCT03527173), conducted between August 2018 and November 2019, evaluated vaccine efficacy (VE), safety, and immunogenicity of a Shigella sonnei GMMA candidate vaccine (1790GAHB) in adults, using a S. sonnei 53 G controlled human infection model. Participants (randomized 1:1) received two doses of 1790GAHB or placebo (GAHB-Placebo), at day (D) 1 and D29, and an oral challenge of S. sonnei 53 G at D57. VE was evaluated using several endpoints, reflecting different case definitions of shigellosis. For the primary endpoint, the success criterion was a lower limit of the 90% confidence interval >0. Findings Thirty-six and 35 participants received 1790GAHB or placebo, respectively; 33 and 29 were challenged, 15 and 12 developed shigellosis. VE was not demonstrated for any endpoint. Adverse events were more frequent in 1790GAHB versus placebo recipients post-vaccination. Anti-S. sonnei lipopolysaccharide (LPS) IgG responses increased at D29 and remained stable through D57 in group 1790GAHB; no increase was shown in placebo recipients. Interpretation 1790GAHB had an acceptable safety profile and induced anti-LPS IgG responses but did not demonstrate clinical efficacy against shigellosis. Baseline/pre-challenge antibody levels were higher in participants who did not develop shigellosis post-challenge, suggesting a role of anti-LPS IgG antibodies in clinical protection, although not fully elucidated in this study. For further vaccine development an increased S. sonnei O-antigen content is likely needed to enhance anti-LPS immune responses. Funding GlaxoSmithKline Biologicals SA, Bill and Melinda Gates Foundation

Background Vaccination against Haemophilus influenzae type b (Hib) is included in routine pediatric immunization schedule in the United States. Previous vaccine shortages have created the need for additional options for Hib vaccination. Methods This phase III, randomized, multi-centered study ( NCT01000974 ) evaluated the safety and immunogenicity of a monovalent tetanus toxoid-conjugate Hib vaccine (Hib-TT) compared to a monovalent (Hib-TT control) and a combination Hib-TT vaccine. We hierarchically assessed lot-to-lot consistency of 3 Hib-TT lots and non-inferiority of Hib-TT to Hib-TT control. We co-administered routine pediatric vaccines with Hib-TT vaccines at 2, 4, 6 months (primary vaccination) and 15–18 months of age (booster vaccination). We recorded adverse events (AEs) for 4 (solicited) and 31 days (unsolicited) post-vaccination and serious AEs (SAEs) throughout the study. Results Of 4009 enrolled children, 3086 completed booster phase. Lot-to-lot consistency was not demonstrated. The study met statistical criteria for non-inferiority of Hib-TT to Hib-TT control in terms of immune responses to Hib and co-administered vaccines’ antigens, but not in terms of participants achieving post-primary vaccination anti-PRP levels ≥1 µg/mL. Because of the hierarchical nature of the objectives, non-inferiority could not be established. In all groups, 92.5–96.7% and 99.6–100% of participants achieved anti-PRP levels ≥0.15 µg/mL, while 78.3–89.8% and 97.9–99.1% had anti-PRP levels ≥1 µg/mL, post-primary and post-booster vaccination, respectively. Immune responses to co-administered vaccines and reported incidence of AEs were comparable among groups. We recorded SAEs for 107/2963 (3.6%), 24/520 (4.6%), and 21/520 (4.0%) children post-primary vaccination, and 29/2337 (1.2%), 4/435 (0.9%), and 2/400 (0.5%) children post-booster vaccination with Hib-TT, Hib-TT control and combination Hib-TT vaccine, respectively; 6/5330 (0.1%) SAEs in the Hib-TT groups were considered vaccine-related. Conclusion Hib-TT induced seroprotective antibody concentrations in the majority of participants and was well-tolerated when co-administered with routine pediatric vaccines according to a 3 + 1 schedule.

Background The decline in immune function with age is a challenge to vaccine development. Following an initial study in adults aged 18–64 years, this study evaluated the safety and immunogenicity of Staphylococcus aureus (S. aureus) 4-antigen (SA4Ag) and 3-antigen (SA3Ag) vaccine in older adults. SA3Ag included capsular polysaccharide serotypes 5 and 8 (CP5 and CP8) conjugated to the nontoxic mutant form of diphtheria toxin (CRM197) and a recombinant version of clumping factor A (ClfA). SA4Ag included these antigens, with the addition of a recombinant manganese transporter C (rP305A or MntC). Both vaccines were unadjuvanted. Methods In this double-blind, sponsor-unblinded, placebo-controlled, phase 1/2 study, 284 healthy adults (aged 65–85 years) were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A, SA3Ag, or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; immunogenicity was also assessed using a competitive Luminex® immunoassay (cLIA). T-cell responses were measured in a small subgroup of subjects using intracellular cytokine staining (ICS) assays. Results The results demonstrated rapid and robust functional immune responses to all antigens in healthy older adults. A high proportion of active vaccine recipients met the pre-defined antibody thresholds for each antigen at Day 29. SA4Ag elicited a dose-level response to rP305A with up to a 13-fold rise in cLIA titres at Day 29. Opsonophagocytic activity (OPA) assays showed >50- and >20-fold rises in functional titres using S. aureus strains expressing CP5 and CP8, respectively, at Day 29. T-cell cytokine responses were not substantially above background levels. There were no safety concerns in this study population and no increases in adverse events with higher rP305A dose levels. Conclusions Single-dose vaccination of SA4Ag and SA3Ag in healthy adults aged 65–85 years safely induced rapid and robust functional immune responses, supporting further development of SA4Ag for the prevention of S. aureus disease in adults up to age 85 years. Trial registration number: NCT01643941 .

Background A prophylactic Staphylococcus aureus four-antigen vaccine (SA4Ag) is under development for prevention of invasive S. aureus disease. A preliminary S. aureus three-antigen vaccine (SA3Ag) was reformulated to include a novel manganese transporter protein (MntC or rP305A). This study describes the first-in-human dose-finding, safety, and immunogenicity results for SA4Ag. Methods In this double-blind, sponsor-unblind, placebo-controlled, phase 1/2 study, 454 healthy adults aged 18–64 years were randomised to receive a single dose of one of three formulations of SA4Ag with escalating dose levels of rP305A or placebo. Functional immune responses were measured using opsonophagocytic activity (OPA) killing and fibrinogen-binding inhibition (FBI) assays; antigen-specific immunogenicity was assessed using a four-plex competitive Luminex® immunoassay (cLIA). Results A high proportion of SA4Ag recipients met the pre-defined antibody thresholds for each antigen at Day 29. A substantial and dose-level dependent immune response was observed for rP305A, with up to 18-fold rises in cLIA titres at Day 29. Robust functional responses were demonstrated, with >80-fold and >20-fold rises in OPA assay titres at Day 29 using S. aureus strains expressing capsular polysaccharide serotypes 5 and 8, respectively. Durable antibody responses were observed through month 12, gradually waning from peak levels achieved by days 11–15. SA4Ag was well tolerated, and no vaccine-related serious adverse events were reported. Conclusions Single-dose vaccination of SA4Ag in healthy adults aged 18–64 years safely induced rapid and robust functional immune responses that were durable through month 12, supporting further development of this vaccine. Trial registration number: NCT01364571

Shigella causes morbidity and mortality worldwide, primarily affecting young children living in low-resource settings. It is also of great concern due to increasing antibiotic resistance, and is a priority organism for the World Health Organization. A Shigella vaccine would decrease the morbidity and mortality associated with shigellosis, improve child health, and decrease the need for antibiotics. Controlled human infection models (CHIMs) are useful tools in vaccine evaluation for early up- or down-selection of vaccine candidates and potentially useful in support of licensure. Over time, the methods employed in these models have become more uniform across sites performing CHIM trials, although some differences in conduct persist. In November 2017, a Shigella CHIM workshop was convened in Washington, District of Columbia. Investigators met to discuss multiple aspects of these studies, including study procedures, clinical and immunological endpoints, and shared experiences. This article serves as a uniform procedure by which to conduct Shigella CHIM studies.

Background Vaccination effectively reduces invasive disease and pneumonia caused by Streptococcus pneumoniae. However, waning antibody titers and the ability of revaccination to boost titers in older adults have been concerns. A study to describe antibody persistence after vaccination with 13-valent pneumococcal conjugate vaccine (PCV13) and response to revaccination 5 years after the initial dose was conducted. Methods Pneumococcal vaccine–naive subjects aged 50–59 years were randomized and vaccinated with PCV13 plus trivalent inactivated influenza vaccine concomitantly or 1 month apart, then revaccinated with PCV13 five years later. Antipneumococcal polysaccharide opsonophagocytic activity (OPA) geometric mean titers (GMTs) and immunoglobulin G (IgG) geometric mean concentrations (GMCs) were determined before and approximately 1 month after each vaccination. Targeted local reactions and systemic events were collected for 14 days, adverse events (AEs) for 1 month, and serious AEs (SAEs) for 6 months after each vaccination. Results Of 1116 randomized subjects, 727 were revaccinated at year 5. Between the time of initial vaccination and revaccination, OPA GMTs and IgG GMCs declined but remained higher than levels before initial vaccination for 12 of the 13 vaccine serotypes. One month after revaccination, OPA GMTs and IgG GMCs were comparable with, or higher than, levels observed 1 month after initial vaccination for most vaccine serotypes. Local reactions were mostly mild. AEs were reported by

Summary Background ExPEC4V (JNJ-63871860) is a bioconjugate vaccine, containing O-antigens from Escherichia coli serotypes O1A, O2, O6A, and O25B, developed for the prevention of invasive extra-intestinal pathogenic E coli (ExPEC) disease. We aimed to assess safety, reactogenicity, and immunogenicity of ExPEC4V in healthy adults. Methods In this phase 2 randomised, double-blind placebo-controlled study, we recruited healthy adults (≥18 years with a body-mass index of 35 kg/m2 or less) between Nov 16, 2015, and Aug 8, 2017, and randomly assigned them to receive a single dose of ExPEC4V (antigen O1A:O2:O6A:O25B content 4:4:4:4 μg [group 1]; 4:4:4:8 μg [group 2], 8:8:8:8 μg [group 3], 8:8:8:16 μg [group 4], or 16:16:16:16 μg [group 5]) or placebo. The primary objectives were evaluation of the safety, tolerability, and immunogenicity of ExPEC4V and determination of its dose-dependent immunogenicity 15 days after vaccination by ELISA in individuals who had received at least one vaccination dose. Antibody titres and safety evaluation were used to select two ExPEC4V doses for assessment up to day 360. This trial is registered at ClinicalTrials.gov, number NCT02546960. Findings Of 848 enrolled participants, 843 (99%) received the ExPEC4V vaccine (757) or placebo (86) and were included in the safety analysis. Of 757 participants vaccinated with ExPEC4V, 222 (29%) had a solicited local adverse event and 325 (43%) had any solicited systemic adverse event, compared with 11 (13%) and 30 (35%) of 86 participants in the control group. Symptoms were mild-to-moderate. The most frequently reported solicited local adverse event was pain or tenderness (205 [27·1%] of 757 in combined ExPEC4V groups) and the most frequently reported solicited systemic adverse event was fatigue (208 [27·6%] of 757). Only 13 (2%) of 843 had a grade 3 event. At day 15, 80% or more of all participants achieved a two times or greater increase in serotype-specific IgG antibodies (except O25B at the lowest dose, 103 [72%] of 144). At day 360, 66% (95% CI 56·47–74·33) of participants in group 2 and 71% (62·13–78·95) of participants in group 4 selected for long-term follow-up maintained a two times or greater increase in serotype-specific antibody compared with baseline. Interpretation EXPEC4V seemed well tolerated and elicited robust and functional antibody responses across all serotypes, doses, and age groups. For the two dosages evaluated (4:4:4:8 μg and 8:8:8:16 μg), the immune response persisted for 1 year. Funding Janssen Pharmaceuticals.

Effective vaccines are needed to combat diarrheal diseases due to Shigella. Two live oral S. sonnei vaccine candidates, WRSs2 and WRSs3, attenuated principally by the lack of spreading ability, as well as the loss of enterotoxin and acyl transferase genes, were tested for safety and immunogenicity. Healthy adults 18–45 years of age, assigned to 5 cohorts of 18 subjects each (WRSs2 (n = 8), WRSs3 (n = 8) or placebo (n = 2)) were housed in an inpatient facility and administered a single oral dose of study agent 5 min after ingestion of oral bicarbonate. Ascending dosages of vaccine (from 103 CFU to 107 CFU) were evaluated. On day 8, treatment with ciprofloxacin (500 mg BID for 3 days) was initiated and subjects were discharged home 2 days after completing antibiotics. Subjects returned for outpatient visits on day 14, 28 and 56 post-vaccination for monitoring and collection of stool and blood samples. Both WRSs2 and WRSs3 were generally well tolerated and safe over the entire dose range. Among the 80 vaccinees, 11 subjects developed diarrhea, 8 of which were mild and did not affect daily activities. At the 107 CFU dose, moderate diarrhea occurred in one WRSs2 subject while at the same dose of WRSs3, 2 subjects had moderate or severe diarrhea. Vaccinees mounted dose-dependent mucosal and systemic immune responses that appeared to correlate with fecal shedding. S. sonnei vaccine candidates WRSs2 and WRSs3 are safe and immunogenic over a wide dose range. Future steps will be to select the most promising candidate and move to human challenge models for efficacy of the vaccine.

Background Based on the success of vaccination with pneumococcal conjugate vaccines (PCVs) in children, recent studies have focused on PCVs in adults. Data from a randomized, double-blind study comparing the immunogenicity, tolerability, and safety of the 13-valent PCV (PCV13) and the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in PPSV23-naive adults 60–64 years of age have been published. The same study also included a cohort of adults aged 18–49 years that received open-label PCV13. The purpose of this cohort was to examine the immunogenicity, safety, and tolerability of PCV13 in adult subjects 18–49 years of age compared with adults 60–64 years of age for whom PCV13 is approved. Methods Adults naive to PPSV23 were grouped by age into 2 cohorts: 18–49 years (n = 899; further stratified by age into 3 subgroups 18–29, 30–39, and 40–49 years) and 60–64 years (n = 417). All subjects received 1 dose of PCV13. In both age groups, immunogenicity was assessed by antipneumococcal opsonophagocytic activity (OPA) geometric mean titers (GMTs) and IgG geometric mean concentrations (GMCs) 1 month after vaccination. Safety and tolerability were evaluated. Results In adults aged 18–49 years, OPA GMTs and IgG GMCs were noninferior for all 13 serotypes and statistically significantly higher for all except 1 serotype (OPA GMT) and 5 serotypes (IgG GMCs) compared with adults 60–64 years. Immune responses were highest in the youngest age subgroup (18–29 years). Local reactions and systemic events were more common in adults 18–49 years compared with 60–64 years and were self-limited. Conclusion Immune responses to PCV13 are robust in adults ≥18 years of age, with highest responses observed in the youngest subgroup. Based on its safety and immunologic profile, PCV13 may serve an important therapeutic role in younger adults, particularly those with underlying medical conditions who have an increased risk of serious pneumococcal infections.

Vancomycin is often required to treat methicillin-resistant Staphylococcus aureus bacteremia in children. Treatment failure occurs in up to 50% of adults and is associated with a 24-hour area under the curve/minimum inhibitory concentration (AUC24h/MIC)400. We sought to identify patient factors associated with vancomycin AUC and whether AUC24h/MIC400 was predictive of treatment failure in children.Hospitalized children younger than 18 years with methicillin-resistant Staphylococcus aureus bacteremia receiving vancomycin were included in a retrospective cohort study. AUC24h was calculated using a validated pharmacokinetic model. Factors such as age, sex, underlying conditions, presence of foreign bodies, patient site of infection, and markers of illness severity were examined for an association with vancomycin AUC, and AUC24h/MIC was evaluated for an association with treatment failure.Subjects requiring intensive care unit support were significantly more likely to have higher vancomycin AUC24h and AUCavg than those subjects not needing intensive care unit support. Although vancomycin serum trough concentrations are predictive of vancomycin AUC, suboptimal exposure of vancomycin occurred in almost 20% of subjects despite trough concentrations within the target range. A relationship between vancomycin AUC24h/MIC and treatment failure could not be established.To ensure optimal AUC/MIC pharmacodynamic index, especially in critically ill patients, estimation of the AUC is critical.

Vancomycin is often required to treat serious infections in children, including methicillin-resistant Staphylococcus aureus infections. The pharmacodynamic index that best predicts efficacy with vancomycin use for methicillin-resistant S. aureus infection in adults is the 24-hour area under the curve (AUC) over the minimum inhibitory concentration. Although multiple pediatric population pharmacokinetic (PK) vancomycin models have been published, few use Bayesian optimization. The current standard of care remains measuring vancomycin serum trough concentrations as a surrogate marker of AUC.A prospective validation of a pediatric population PK model of vancomycin was performed. Hospitalized children younger than 18 years receiving vancomycin at Cincinnati Children's Hospital Medical Center were invited to participate. Peak, trough, and random vancomycin serum concentrations were used for Bayesian estimation of individual PK parameters. Model covariates included age, weight, and serum creatinine. To evaluate the predictive performance of the model, precision and bias were measured and compared using the 95% confidence interval.Fifteen subjects were enrolled; 13 subjects had vancomycin serum concentrations drawn per protocol. Of those 13 subjects, the median age was 6 years and 54% were male. Significant medical conditions included cancer (54%), lung disease (23%), neurologic disorders (23%), and prior transplantation (15%). The initial serum creatinine was normal (median, 0.33; interquartile range, 0.23-0.4 mg/dL), and none had underlying renal dysfunction. Equivalence of bias and precision between the original model validation and the Cincinnati Children's Hospital Medical Center validation were found.Pediatric population PK models for vancomycin with Bayesian estimation can be used to reliably predict vancomycin exposure in children. Using AUC instead of trough serum concentrations alone can provide an opportunity to maximally optimize vancomycin administration in children.

The controlled human infection model (CHIM) to assess the efficacy of vaccines against Shigella and enterotoxigenic Escherichia coli (ETEC) has several unique features that could significantly enhance the ability to test candidate vaccines. Despite increasing interest in these models, questions remain as to how to best incorporate them into vaccine development and how to maximize results. We designed a workshop focused on CHIM as part of the Vaccines Against Shigella and ETEC (VASE) Conference. The workshop, using the World Cafe method, focused on; clinical outcomes, nonclinical outcomes and model standardization. Researchers with a variety of expertise and experience rotated through each focus area and discussed relevant sub-topics. The results of these discussions were presented and questions posed to guide future workshops. Clinical endpoint discussions focused on the need for harmonized definitions; optimized attack rates; difficulties of sample collection and a need for non-stool based endpoints. Nonclinical discussions centered on evolving omics-based opportunities, host predictors of susceptibility and novel characterizations of the immune response. Model standardization focused on the value of shared procedures across institutions for clinical and non-clinical endpoints as well as for strain preparation and administration and subject selection. Participants agreed CHIMs for Shigella and ETEC vaccine development could accelerate vaccine development of a promising candidate; however, it was also appreciated that variability in the model and our limited understand of the host-pathogen interaction may yield results that could negatively impact a suitable candidate. Future workshops on CHIM are needed to ensure the optimal application of these models moving forward.

Background Vaccines against norovirus, the leading cause of acute gastroenteritis, should protect against medically significant illness and reduce transmission. Methods In this randomized, double-blind, placebo-controlled trial, 18- to 50-year-olds received 2 injections of placebo or norovirus GI.1/GII.4 bivalent vaccine-like particle (VLP) vaccine with 3-O-desacyl-4'-monophosphoryl lipid A (MPL) and alum. Participants were challenged as inpatients with GII.4 virus (4400 reverse transcription polymerase chain reaction [RT-PCR] units), and monitored for illness and infection. Results Per protocol, 27 of 50 (54.0%) vaccinees and 30 of 48 (62.5%) controls were infected. Using predefined illness and infection definitions, vaccination did not meet the primary endpoint, but self-reported cases of severe (0% vaccinees vs. 8.3% controls; P = .054), moderate or greater (6.0% vs. 18.8%; P = .068), and mild or greater severity of vomiting and/or diarrhea (20.0% vs. 37.5%; P = .074) were less frequent. Vaccination also reduced the modified Vesikari score from 7.3 to 4.5 (P = .002). Difficulties encountered were low norovirus disease rate, and inability to define illness by quantitative RT-PCR or further antibody rise in vaccinees due to high vaccine-induced titers. By day 10, 11 of 49 (22.4%) vaccinees were shedding virus compared with 17 of 47 (36.2%) placebo recipients (P = .179). Conclusions Bivalent norovirus VLP vaccine reduced norovirus-related vomiting and/or diarrhea; field efficacy studies are planned. Clinical Trials Registration. NCT01609257.

A total of 220 enteroadherent Escherichia coli were identified from 729 Egyptian children with diarrhea using the HEp-2 adherence assay. Enteropathogenic E.coli (EPEC = 38) was common among children

Aim: Determine if individuals with β-lactam induced neutropenia have polymorphisms that impair function of MRP4 or OAT1/OAT3. Methods: Subjects with β-lactam induced neutropenia were compared to controls for the presence of MRP4 and OAT1/OAT3 polymorphisms, estimated plasma trough concentrations and area under the curve. Results: Subjects with a homozygous polymorphism at MRP4 3348 A to G were 5.3 times more likely to develop neutropenia (p = 0.171). No statistical differences were noted in pharmacokinetic parameters. Contingency analysis of children greater than 5 years of age showed neutropenia in subjects who were homozygous wild type at MRP4 3348 A to G was significantly associated with standard or high dosing (p = 0.03). Conclusion: MRP4 3348 A to G should be further studied for potential contribution to the development of β-lactam induced neutropenia.

Significant advancements in the care of children with cardiac valve disease over the past 15 years have led to the increasingly common use of percutaneous transcatheter valve implantation as an alternative to surgical replacement in selected patient populations. Although the transcatheter approach has several advantages, this approach and the valves used are not without complications. Bacterial endocarditis is a known and concerning complication after transcatheter pulmonary valve replacement (TPVR). Most reported cases have involved organisms that are common etiologic agents of bacterial endocarditis and are readily identified via blood culture. However, culture-negative endocarditis in the setting of TPVR has not been well described. We present our experience with one afebrile teenager with culture-negative, serology-positive Bartonella henselae endocarditis of a Melody valve 18 months after TPVR for management of tetralogy of Fallot. The teen was successfully managed with long-term antibiotic therapy followed by surgical replacement of the valve. To our knowledge, this is the first reported case of culture-negative endocarditis of a Melody TPVR in the absence of fever. This report discusses the importance of considering culture-negative endocarditis in the differential diagnosis of an afebrile patient with TPVR presenting with constitutional symptoms and valve dysfunction, particularly in the primary care setting. It is anticipated that with an increase in the successfully aging population of children who have undergone cardiac repair, the evaluation of these patients will become an increasingly important and common task for the community pediatrician.

A randomized, double-blind, phase 3 trial evaluated the immunogenicity, safety, and tolerability of a 13-valent pneumococcal conjugate vaccine (PCV13) coadministered with trivalent inactivated influenza vaccine (TIV) in pneumococcal vaccine-naive adults. Participants ages 50 to 59 years (n= 1,116) received TIV with PCV13 (group 1) or placebo (group 2) (1:1 randomization); 1 month later, group 1 received placebo and group 2 received PCV13. A hemagglutination inhibition (HAI) assay for TIV and a standardized enzyme-linked immunosorbent assay for pneumococcal serotype-specific immunoglobulin G (IgG) were performed and opsonophagocytic activity (OPA) titers (assessedpost hoc) were measured at baseline and 1 and 2 months postvaccination. The rises in HAI assay geometric mean titer (GMT) and percentage of participants in groups 1 and 2 with ≥4-fold increases in HAI responses (A/H1N1, 84.0% and 81.2%, respectively; A/H3N2, 71.1% and 69.5%, respectively; and B, 60.6% and 60.3%, respectively) were similar. In group 1, all serotypes met the predefined IgG geometric mean concentration (GMC) ratio noninferiority criterion relative to group 2, but GMCs were lower in group 1 than group 2. When comparing group 1 with group 2, 5 serotypes did not meet the OPA GMT ratio noninferiority criterion, and OPA GMTs were significantly lower for 10 serotypes. PCV13 injection site reactions were similar and mostly mild in both groups. Systemic events were more frequent in group 1 (86.2%) than group 2 (76.7%;P< 0.001); no vaccine-related serious adverse events occurred. Coadministration of PCV13 and TIV was well tolerated but associated with lower PCV13 antibody responses and is of unknown clinical significance. Given the positive immunologic attributes of PCV13, concomitant administration with TIV should be dictated by clinical circumstances.

BACKGROUND: Long-term immunosuppressive medications are being used more commonly for a variety of medical conditions, including immune-mediated diseases and organ transplantation. While these medications are often necessary, they are associated with an increased risk of serious infections. Vaccination may be a way to prevent a variety of infections but vaccine responses among patients receiving immunosuppressive therapies have been variable. PURPOSE: To systematically review the literature describing immune responses among patients on immunosuppressive therapies to vaccinations including influenza, pneumococcal, meningococcal, hepatitis A and B, tetanus toxoid, pertussis, varicella, and zoster. DATA SOURCES: English language citations in the MEDLINE and EMBASE databases from 1985 to 2010. STUDY SELECTION: Two reviewers independently screened titles and abstracts to identify prospective, controlled studies reporting pre- and post-vaccination titers of recommended vaccines in patients receiving long-term immunosuppressive therapies for full-text review. DATA EXTRACTION: Three reviewers independently assessed study characteristics including treatment regimens and pre- and post-vaccination titers. DATA SYNTHESIS: Of the 972 identified titles, fifteen met inclusion criteria. Ten studies assessed the effects of immunosuppressive medications on responses to influenza vaccine, four studies investigated responses following pneumococcal vaccination, and one study assessed both influenza and pneumococcal vaccination. Five of the studies that evaluated influenza vaccination showed partially diminished responses among individuals receiving immunosuppressive therapies, while one of the pneumococcal vaccine studies showed significantly decreased responses following vaccination. Patients treated with more than one immunosuppressive medication were the least likely to respond to vaccination. LIMITATIONS: The heterogeneity of reported outcomes limits generalizeability. CONCLUSIONS: Immunosuppressive therapy, particularly combination regimens, may blunt response to influenza and pneumococcal vaccinations. To ensure the best chance of response, immunizations should be administered prior to initiation of immunosuppressive medications whenever possible.

Worldwide, Streptococcus pneumoniae causes significant morbidity and mortality. The 23-valent pneumococcal polysaccharide vaccine (PPSV23) has been recommended for use in persons aged 65 years and over and in adults with certain chronic medical conditions. Pneumococcal conjugate vaccines (PCVs) have been developed for use in infants and children aged less than 5 years, and are being studied for use in adult populations.The different types of pneumococcal vaccines are discussed. Studies comparing PPSV23 and PCVs, as well as the results of the widespread use of 7-valent PCV are covered. The possible extension of the use of 13-valent PCV to adults, particularly to vulnerable populations, is discussed. The MEDLINE database was used to identify relevant studies from literature published in English between January 1977 and January 2011. All studies of adults aged over 18 years were considered for the review.Elderly individuals and adults with chronic medical conditions who are at increased risk for pneumococcal disease would benefit from more effective prevention than is provided by the currently recommended PPSV23.

The aim of the study was to determine whether reduced doses of trivalent inactivated influenza vaccine (TIV) administered by the intradermal (ID) route generated similar immune responses to standard TIV given intramuscularly (IM) with comparable safety profiles. Recent changes in immunization recommendations have increased the number of people for whom influenza vaccination is recommended. Thus, given this increased need and intermittent vaccine shortages, means to rapidly expand the vaccine supply are needed. Previously healthy subjects 18-64 years of age were randomly assigned to one of four TIV vaccine groups: standard 15 μg HA/strain TIV IM, either 9 μg or 6 μg HA/strain of TIV ID given using a new microinjection system, (BD Soluvia™ Microinjection Systema), or 3 μg HA/strain of TIV ID given by Mantoux technique. All vaccines contained A/New Caledonia (H1N1), A/Wyoming (H3N2) and B/Jiangsu strains of influenza. Sera were obtained 21 days after vaccination and hemagglutination inhibition (HAI) assays were performed and geometric mean titers (GMT) were compared among the groups. Participants were queried immediately following vaccination regarding injection pain and quality of the experience. Local and systemic reactions were collected for 7 days following vaccination and compared. Ten study sites enrolled 1592 subjects stratified by age; 18-49 years, [N=814] and 50-64 years, [N=778]. Among all subjects, for each of the three vaccine strains, the GMTs at 21 days post-vaccination for both the 9 μg and the 6 μg doses of each strain given ID were non inferior to GMTs generated after standard 15 μg doses/strain IM. However, for the 3 μg ID dose, only the A/Wyoming antigen produced a GMT that was non-inferior to the standard IM dose. Additionally, in the subgroup of subjects 50-64 years of age, the 6 μg dose given ID induced GMTs that were inferior to the standard IM TIV for the A/H1N1 and B strains. No ID dose produced a GMT superior to that seen after standard IM TIV. Local erythema and swelling were significantly more common in the ID groups but the reactions were mild to moderate and short-lived. No significant safety issues related to intradermal administration were identified. Participants given TIV ID provided favorable responses to questions about their experiences with ID administration. In conclusion, for the aggregated cohorts of adults 18 to 64 years of age, reduced doses (6 μg and 9 μg) of TIV delivered ID using a novel microinjection system stimulated comparable HAI antibody responses to standard TIV given IM. The reduced 3 μg dose administered ID by needle and syringe, as well as the 6 μg ID for subjects aged 50-64 years of age generated poorer immune responses as compared to the 15 μg IM dose.

To better understand the epidemiology of diarrhea in deployed personnel to the Middle East, a prospective cohort study of travelers' diarrhea (TD) was conducted between May 2004 and January 2005 at the Multinational Force and Observers (MFO) camp in the southern Sinai. A baseline entry questionnaire and stool specimen was provided on study entry, and volunteers were followed every 6 weeks. Of 211 volunteers, 145 (68.7%) completed one or more follow-up visits. In total, 416 follow-up surveys were completed, which described an overall incidence of 25.2 episodes per 100 person months (95% confidence interval = 21.2-30.0). Additionally, stools were collected in 72 of 77 diarrhea-associated clinic visits, with bacterial pathogens most commonly isolated (enterotoxigenic Escherichia coli in 30 [42%] samples and Campylobacter jejuni in 7 [10%] samples) Despite modern preventive methods, diarrhea is still a common problem for deployed US military personnel in Egypt, frequently resulting in diminished ability to work.

The treatment of inflammatory bowel disease (IBD) often includes immunosuppressive medications, which may increase the risk of vaccine-preventable illnesses. We aimed to assess the impact of immunosuppression on immune responses to pneumococcal vaccination in patients with IBD.The study design consists of a prospective controlled clinical trial. This study was carried out at a tertiary-care IBD clinic. The subjects for the study belonged to one of the following three groups: adult patients with IBD on combination TNF-blockers and immunomodulators (Group A), those without immunosuppressive therapy (Group B), and age-matched healthy controls (Group C). The treatment consisted of immunization with 23-valent pneumococcal polysaccharide vaccines (PSVs). The main outcome was immune response for five serotypes defined as a twofold or greater increase from pre-vaccination titers andor =1 microg post-vaccination titer.Sixty-four subjects participated in the study: 20 in Group A, 25 in Group B, and 19 in Group C. Pre-vaccination titers were similar among the three groups. Vaccine responses were lower in Group A than in Group B (Por =0.01 for four out of five antigens) and Group C (P0.01 for all five antigens). Overall vaccine response was seen in 45, 80, and 85% of Groups A, B, and C (P=0.01), respectively.Immune response to PSV-23 is impaired in Crohn's disease (CD) patients on combination immunosuppressive therapy but is normal among non-immunosuppressed patients. Given the unpredictable likelihood for immunosuppressive therapy, newly diagnosed patients with IBD should undergo vaccination before the initiation of immunosuppressive therapy.

Palivizumab was licensed in June 1998 by the US Food and Drug Administration for prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in pediatric patients who are at increased risk of severe disease. Safety and efficacy have been established for infants born at or before 35 weeks' gestation with or without chronic lung disease of prematurity and for infants and children with hemodynamically significant heart disease. The American Academy of Pediatrics (AAP) published a policy statement on the use of palivizumab in November 1998 (American Academy of Pediatrics, Committee on Infectious Diseases and Committee on Fetus and Newborn. Pediatrics. 1998;102[5]:1211–1216) and revised it in December 2003 (American Academy of Pediatrics, Committee on Infectious Diseases and Committee on Fetus and Newborn. Pediatrics. 2003;112[6 pt 1]:1442–1446), and an AAP technical report on palivizumab was published in 2003 (Meissner HC, Long SS; American Academy of Pediatrics, Committee on Infectious Diseases and Committee on Fetus and Newborn. Pediatrics. 2003;112[6 pt 1]:1447–1452). On the basis of the availability of additional data regarding seasonality of RSV disease as well as the limitations in available data on risk factors for identifying children who are at increased risk of serious RSV lower respiratory tract disease, AAP recommendations for immunoprophylaxis have been updated in an effort to ensure optimal balance of benefit and cost from this expensive intervention. This statement updates and replaces the 2003 AAP statement and the 2006 Red Book and is consistent with the 2009 Red Book recommendations.

Brucellosis, an infectious disease transmitted to humans principally through exposure to contaminated milk products, is endemic to the Middle East [1]. In Egypt, a crosssectional study found that 11% of the population had serological evidence of infection with Brucella spp., while a study of acute febrile illnesses found that 3% of all bacteraemias were caused by the organism [2,3]. Brucella spp. has been reported as a cause of meningitis in many parts of the world. But, despite the frequent finding of Brucella bacteraemia, as far as we know the agent has not been previously reported in the medical literature as a cause of meningitis in Egypt. The current case thus represents the first report of cerebrospinal fluid (CSF) culturepositive Brucella meningitis in Egypt.

This statement updates and replaces the 2007 American Academy of Pediatrics statement for prevention of rotavirus gastroenteritis. In February 2006, a live oral human-bovine reassortant rotavirus vaccine (RV5 [RotaTeq]) was licensed as a 3-dose series for use in infants in the United States. The American Academy of Pediatrics recommended routine use of RV5 in infants in the United States. In April 2008, a live, oral, human attenuated rotavirus vaccine (RV1 [Rotarix]) was licensed as a 2-dose series for use in infants in the United States. The American Academy of Pediatrics recommends routine immunization of infants in the United States with rotavirus vaccine. The American Academy of Pediatrics does not express a preference for either RV5 or RV1. RV5 is to be administered orally in a 3-dose series with doses administered at 2, 4, and 6 months of age; RV1 is to be administered orally in a 2-dose series with doses administered at 2 and 4 months of age. The first dose of rotavirus vaccine should be administered from 6 weeks through 14 weeks, 6 days of age. The minimum interval between doses of rotavirus vaccine is 4 weeks. All doses should be administered by 8 months, 0 days of age. Recommendations in this statement also address the maximum ages for doses, contraindications, precautions, and special situations for administration of rotavirus vaccine.