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BackgroundBaricitinib and dexamethasone have randomised trials supporting their use for the treatment of patients with COVID-19. We assessed the combination of baricitinib plus remdesivir versus dexamethasone plus remdesivir in preventing progression to mechanical ventilation or death in hospitalised patients with COVID-19.MethodsIn this randomised, double-blind, double placebo-controlled trial, patients were enrolled at 67 trial sites in the USA (60 sites), South Korea (two sites), Mexico (two sites), Singapore (two sites), and Japan (one site). Hospitalised adults (≥18 years) with COVID-19 who required supplemental oxygen administered by low-flow (≤15 L/min), high-flow (>15 L/min), or non-invasive mechanical ventilation modalities who met the study eligibility criteria (male or non-pregnant female adults ≥18 years old with laboratory-confirmed SARS-CoV-2 infection) were enrolled in the study. Patients were randomly assigned (1:1) to receive either baricitinib, remdesivir, and placebo, or dexamethasone, remdesivir, and placebo using a permuted block design. Randomisation was stratified by study site and baseline ordinal score at enrolment. All patients received remdesivir (≤10 days) and either baricitinib (or matching oral placebo) for a maximum of 14 days or dexamethasone (or matching intravenous placebo) for a maximum of 10 days. The primary outcome was the difference in mechanical ventilation-free survival by day 29 between the two treatment groups in the modified intention-to-treat population. Safety analyses were done in the as-treated population, comprising all participants who received one dose of the study drug. The trial is registered with ClinicalTrials.gov, NCT04640168.FindingsBetween Dec 1, 2020, and April 13, 2021, 1047 patients were assessed for eligibility. 1010 patients were enrolled and randomly assigned, 516 (51%) to baricitinib plus remdesivir plus placebo and 494 (49%) to dexamethasone plus remdesivir plus placebo. The mean age of the patients was 58·3 years (SD 14·0) and 590 (58%) of 1010 patients were male. 588 (58%) of 1010 patients were White, 188 (19%) were Black, 70 (7%) were Asian, and 18 (2%) were American Indian or Alaska Native. 347 (34%) of 1010 patients were Hispanic or Latino. Mechanical ventilation-free survival by day 29 was similar between the study groups (Kaplan-Meier estimates of 87·0% [95% CI 83·7 to 89·6] in the baricitinib plus remdesivir plus placebo group and 87·6% [84·2 to 90·3] in the dexamethasone plus remdesivir plus placebo group; risk difference 0·6 [95% CI -3·6 to 4·8]; p=0·91). The odds ratio for improved status in the dexamethasone plus remdesivir plus placebo group compared with the baricitinib plus remdesivir plus placebo group was 1·01 (95% CI 0·80 to 1·27). At least one adverse event occurred in 149 (30%) of 503 patients in the baricitinib plus remdesivir plus placebo group and 179 (37%) of 482 patients in the dexamethasone plus remdesivir plus placebo group (risk difference 7·5% [1·6 to 13·3]; p=0·014). 21 (4%) of 503 patients in the baricitinib plus remdesivir plus placebo group had at least one treatment-related adverse event versus 49 (10%) of 482 patients in the dexamethasone plus remdesivir plus placebo group (risk difference 6·0% [2·8 to 9·3]; p=0·00041). Severe or life-threatening grade 3 or 4 adverse events occurred in 143 (28%) of 503 patients in the baricitinib plus remdesivir plus placebo group and 174 (36%) of 482 patients in the dexamethasone plus remdesivir plus placebo group (risk difference 7·7% [1·8 to 13·4]; p=0·012).InterpretationIn hospitalised patients with COVID-19 requiring supplemental oxygen by low-flow, high-flow, or non-invasive ventilation, baricitinib plus remdesivir and dexamethasone plus remdesivir resulted in similar mechanical ventilation-free survival by day 29, but dexamethasone was associated with significantly more adverse events, treatment-related adverse events, and severe or life-threatening adverse events. A more individually tailored choice of immunomodulation now appears possible, where side-effect profile, ease of administration, cost, and patient comorbidities can all be considered.FundingNational Institute of Allergy and Infectious Diseases.

Antimicrobial resistance is a global health threat. To slow resistance and preserve antibiotics, stewardship interventions are increasingly promoted and mandated. Urine cultures are the most common microbiological test in the outpatient setting. Contamination most likely occurs during urine collection from surrounding vaginal, perineal, and epidermal flora. Sample contamination can lead to incorrect diagnosis, unnecessary or inappropriate treatment, poor patient outcomes, and higher costs. Therefore, ensuring proper collection of urinary samples serves as a prime diagnostic stewardship target, one that international nursing societies increasingly endorse as an opportunity for nurse involvement.Determine the prevalence, predictors, and antibiotic prescribing associated with contaminated urine cultures in primary care clinics.Cross-sectional study.Two adult safety-net clinics in Houston, Texas.1265 clinical encounters among 1114 primary care patients.We reviewed charts from office visits among patients who had a urine culture ordered between November 2018 and March 2020. Patient demographics, culture results and prescription orders were captured for each visit. Culture results were defined as no growth, contaminated (i.e., mixed flora, non-uropathogens, or ≥3 bacterial species isolated), or low-count (10Our study evaluated 1265 cultures from 1114 patients that were primarily female (84 %), of Hispanic/Latino (74.4 %) or Black/African American (18.9 %) race/ethnicity with a mean age of 43 years. Out of 1265 urine cultures, 264 (20.9 %) had no growth, 694 (54.9 %) were contaminated, 159 (12.6 %) were low-count positive, and 148 (11.7 %) were high-count positive. Female sex, pregnancy, and obesity were associated with contaminated cultures (multinomial adjusted odds ratios: 15.89, 14.34, 1.93, respectively; 95 % confidence intervals: 10.25-24.61, 8.03-25.61, 1.32-2.81, respectively). Antibiotic prescribing was significantly higher among symptomatic patients with contaminated cultures compared to those with no growth.Urine culture contamination occurred frequently in our clinics, and obesity, female sex and pregnancy were independent risk factors for contamination. The association of pregnancy and contamination is particularly concerning as pregnant females are routinely screened and treated for asymptomatic bacteriuria in the United States. Culture contamination may obscure underlying uropathogens, leading to pyelonephritis or potential neonatal infection if untreated. Conversely, overtreatment of false positive bacteriuria could lead to adverse effects from antibiotics and increased risk for antibiotic resistance. As nurses play a prominent role in patient education, diagnostic stewardship interventions may want to utilize nurses' educational capabilities to improve urine culture collection.55 % of urine cultures collected in primary care clinics were contaminated, revealing a major opportunity for nurse-driven diagnostic stewardship interventions.

BACKGROUND: Schistosomiasis caused by Schistosoma mansoni (Sm) is a chronic, debilitating and potentially deadly neglected tropical disease. The licensure of a vaccine to prevent schistosomiasis would represent a major breakthrough in public health. METHODS: The safety and immunogenicity of a candidate Sm vaccine were assessed in this phase I, double-blind, dose-escalation trial. Seventy-two healthy Sm-naïve 18–50 year olds were randomized to receive 3 doses~ 8 weeks apart of saline placebo, or 10 μg, 30 μg, or 100 μg of recombinant Sm-Tetraspanin-2 vaccine formulated on aluminum hydroxide adjuvant (Sm-TSP-2/Al) with or without 5 μg of glucopyranosyl lipid A aqueous formulation (GLA-AF). Clinical and serologic responses were assessed for 1 year after dose 3. RESULTS: Vaccines were safe and well-tolerated. The most common reactions were injection site tenderness and pain, and headache and fatigue. Tenderness and pain were more frequent in groups receiving vaccine with GLA-AF than placebo (p = 0.0036 and p = 0.0014, respectively). Injection site reactions among those given Sm-TSP-2/Al with GLA-AF lasted 1.22 and 1.33 days longer than those receiving Sm-TSP-2/Al without GLA-AF or placebo (p < 0.001 for both). Dose- and adjuvant-related increases in serum IgG against Sm-TSP-2 were observed. Peak IgG levels occurred 14 days after dose 3. Seroresponse frequencies were low among recipients of Sm-TSP-2/Al without GLA-AF, but higher among subjects receiving 30 μg or 100 μg of Sm-TSP-2/Al with GLA-AF. More seroresponses were observed among those given 30 μg or 100 μg of Sm-TSP-2/Al with GLA-AF compared to placebo (p = 0.023 and p < 0.001, respectively). Seroresponse frequencies were 0%, 30%, 50%, and 89%, respectively, among those given placebo, or 10 μg, 30 μg or 100 μg of Sm-TSP-2/Al with GLA-AF, suggesting a dose-response relationship for Sm-TSP-2/Al with GLA-AF (p = 0.0001). CONCLUSIONS: Sm-TSP-2/Al with or without GLA-AF was safe and well tolerated in a Sm-naïve population. A vaccine like the one under development may represent our best hope to eliminating this neglected tropical disease.

Recent studies have suggested that among those receiving seasonal influenza vaccine (SIV), reduced immunogenicity is observed in recently vaccinated (RV; within the past season or 2) persons when compared with those not recently vaccinated (NRV). We performed a meta-analysis to assess the effect of recent immunization with SIV on serum H5 hemagglutination inhibition (HAI) antibody responses after influenza A/H5N1 vaccination using data from a series of randomized controlled trials. The primary outcome was seroconversion measured by HAI assays following receipt of 2 doses of H5N1 vaccine. The geometric mean titer (GMT) of serum HAI antibody after vaccination was the secondary outcome. Analyses were performed using propensity score (PS) matching. The PS for each individual in the meta-analysis cohort was calculated using logistic regression and covariates included age, gender, race, antigen dose, adjuvant, statin use and vaccine manufacturer. 2015 subjects enrolled in 7 clinical trials were eligible for inclusion in the meta-analysis cohort; among these, 915 (45%) were RV. 901 RV subjects were matched (1:1) with replacement to a subject who was NRV. Subjects who received SIV within the previous season were significantly less likely to seroconvert following H5N1 vaccination (adjusted odds ratio 0.76; 95%CI 0.60–0.96; p = 0.024), and the GMT was 18% higher among NRV subjects (GM ratio of HAI antibody 1.18; 95%CI 1.04–1.33; p = 0.008). Further work is needed to better define the effects of, and mechanisms contributing to, reduced immune responses to H5N1 vaccine among RV subjects.

Objective In response to the emergence of influenza viruses with pandemic potential, we evaluated a swine-origin influenza A/H3N2 variant (H3N2v) vaccine in children. Study design This multicenter phase II open-label study assessed the safety and immunogenicity of two doses, 21 days apart, of investigational unadjuvanted subvirion monovalent inactivated H3N2v vaccine administered via intramuscular injection. Children 6–35 months of age received 7.5mcg or 15mcg of hemagglutinin (HA)/dose; children 3–17 years of age received 15mcg HA/dose. Safety and reactogenicity were assessed by measuring the occurrence of solicited injection site and systemic reactions in the 7 days after each vaccination; adverse events were assessed for 42 days and serious adverse events for 7 months after the first vaccination. Immunogenicity was evaluated by measuring hemagglutination inhibition (HAI) and neutralizing (Neut) antibodies to H3N2v prior to and 21 days after each vaccination. Cross-reactivity against seasonal H3N2 strains was evaluated. Results The H3N2v vaccine was well tolerated. Transient mild to moderate injection site tenderness, pain and erythema was observed, with the most commonly reported systemic reactogenicity being irritability in children 6–35 months, and headache and fatigue in children 9–17 years old. Children 6–35 months old, whether they received 7.5mcg or 15mcg/dose, had low HAI and Neut antibody responses after two doses compared to older children. Children under 9 years of age required two doses of vaccine to demonstrate a response, while 9–17 year olds responded well after one dose. Previous influenza vaccination and older age were associated with higher immune responses to H3N2v vaccine. Children 9–17 years of age also developed cross-reactive antibodies against recent seasonal H3N2 influenza viruses. Conclusion The H3N2v vaccine was safe and immunogenic in children and adolescents. Age-related increases in immunogenicity against H3N2v and seasonal H3N2 viruses were observed, suggesting prior priming via infection and/or immunization. Clinical trial registry: The trial is registered with clinicaltrial.gov: NCT02100436 .

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibits reduced susceptibility to vaccine-induced neutralizing antibodies, requiring a boost to generate protective immunity. We assess the magnitude and short-term durability of neutralizing antibodies after homologous and heterologous boosting with mRNA and Ad26.COV2.S vaccines. All prime-boost combinations substantially increase the neutralization titers to Omicron, although the boosted titers decline rapidly within 2 months from the peak response compared with boosted titers against the prototypic D614G variant. Boosted Omicron neutralization titers are substantially higher for homologous mRNA vaccine boosting, and for heterologous mRNA and Ad26.COV2.S vaccine boosting, compared with homologous Ad26.COV2.S boosting. Homologous mRNA vaccine boosting generates nearly equivalent neutralizing activity against Omicron sublineages BA.1, BA.2, and BA.3 but modestly reduced neutralizing activity against BA.2.12.1 and BA.4/BA.5 compared with BA.1. These results have implications for boosting requirements to protect against Omicron and future variants of SARS-CoV-2. This trial was conducted under ClincalTrials.gov: NCT04889209.

Background & Aims Human noroviruses are responsible for approximately 200,000 deaths worldwide each year. In 2012, the GII.4 Sydney strain emerged and became the major circulating norovirus strain associated with human disease. Our understanding of the human norovirus-specific antibody response is limited because few human monoclonal antibodies (mAbs) to noroviruses have been described, and there are no functional assays to measure virus neutralization. We studied the antibody-mediated response to the genogroup (G) II.4 strain by isolating mAbs to GII.4 from infected patients and developing virus neutralization assays. Methods We used a robust human hybridoma technique to isolate mAbs from patients previously infected with norovirus and identified mAbs that blocked virus binding to cell receptors, using virus-like particles to test blockade ability. We tested the ability of select mAbs to neutralize live human noroviruses using stem cell–derived human enteroids. Results We isolated a panel of 25 IgG or IgA human mAbs that recognized norovirus GII.4 Sydney 2012 and determined their potential to block virus binding to cell receptors. In competition binding studies, most antibodies recognized 3 major antigenic sites on the GII.4 Sydney 2012 protruding (P) domain. Conclusions We isolated and characterized human mAbs that neutralize live human norovirus GII.4 Sydney 2012—the predominant strain responsible for recent outbreaks. Analyses of these antibodies identified neutralizing epitopes; further studies will provide insight into the human immune response to this deadly virus.

Background Tularemia is caused by Francisella tularensis , a gram-negative bacterium that has been weaponized as an aerosol. For protection of personnel conducting biodefense research, the United States Army required clinical evaluation of a new lot of tularemia live vaccine strain manufactured in accordance with Current Good Manufacturing Practices. Methods A phase 2 randomized clinical trial compared the new lot (DVC-LVS) to the existing vaccine that has been in use for decades (USAMRIID-LVS). The vaccines were delivered by scarification to 228 participants. Safety, reactogenicity, take and/or antibody levels were assessed on days 0, 1, 2, 8, 14, 28, 56, and 180. Principal Results Both vaccines were safe and had acceptable reactogenicity profiles during six months of follow-up. There were no serious or grade 3 and 4 laboratory adverse events. Moderate systemic reactogenicity (mostly headache or feeling tired) was reported by ∼23% of participants receiving either vaccine. Injection site reactogenicity was mostly mild itchiness and pain. The frequencies of vaccine take skin reactions were 73% (95% CI, 64, 81) for DVC-LVS and 80% (95% CI, 71, 87) for USAMRIID-LVS. The 90% CI for the difference in proportions was −6.9% (−16.4, 2.6). The rates of seroconversion measured by microagglutination assay on days 28 or 56 were 94% (95% CI, 88, 98; n = 98/104) for DVC-LVS and 94% (95% CI, 87, 97; n = 103/110) for USAMRIID-LVS (p = 1.00). Day 14 sera revealed more rapid seroconversion for DVC-LVS relative to USAMRIID-LVS: 82% (95% CI, 73, 89) versus 55% (95% CI, 45, 65), respectively (p Major conclusions The DVC-LVS vaccine had similar safety, reactogenicity, take and antibody responses compared to the older USAMRIID vaccine, and was superior for early (day 14) antibody production. Vaccination take was not a sensitive surrogate for seroconversion in a multi-center study where personnel at five research clinics performed assessments. ClinicalTrials.gov identifier NCT01150695

Recognition and binding to host glycans present on cellular surfaces is an initial and critical step in viral entry. Diverse families of host glycans such as histo-blood group antigens, sialoglycans and glycosaminoglycans are recognized by viruses. Glycan binding determines virus-host specificity, tissue tropism, pathogenesis and potential for interspecies transmission. Viruses including noroviruses, rotaviruses, enteroviruses, influenza, and papillomaviruses have evolved novel strategies to bind specific glycans often in a strain-specific manner. Structural studies have been instrumental in elucidating the molecular determinants of these virus-glycan interactions, aiding in developing vaccines and antivirals targeting this key interaction. Our review focuses on these key structural aspects of virus-glycan interactions, particularly highlighting the different strain-specific strategies employed by viruses to bind host glycans.

Human noroviruses are major causative agents of sporadic and epidemic gastroenteritis both in children and adults. Currently there are no licensed therapeutic intervention measures either in terms of vaccines or drugs available for these highly contagious human pathogens. Genetic and antigenic diversity of these viruses, rapid emergence of new strains, and their ability to infect a broad population by using polymorphic histo-blood group antigens for cell attachment, pose significant challenges for the development of effective antiviral agents. Despite these impediments, there is progress in the design and development of therapeutic agents. These include capsid-based candidate vaccines, and potential antivirals either in the form of glycomimetics or designer antibodies that block HBGA binding, as well as those that target essential non-structural proteins such as the viral protease and RNA-dependent RNA polymerase. In addition to these classical approaches, recent studies suggest the possibility of interferons and targeting host cell factors as viable approaches to counter norovirus infection. This review provides a brief overview of this progress.

Purpose The study aims were to determine whether inactivated influenza A/H5N1 vaccine administration elicited cell mediated immune (CMI) responses and the impact of adjuvant, vaccine dose and subject age on these responses. Methods Adults who were previously primed with either adjuvanted or unadjuvanted, inactivated, A/H5N1/Vietnam/1203/2004 (Clade 1) vaccine or unprimed (received placebo) in previous vaccine studies were randomized to receive one (primed) or two (unprimed) 15- or 90-mcg doses of inactivated, A/H5N1/Indonesia/05/05 (Clade 2) vaccine. Peripheral blood mononuclear cells (PBMCs) were collected and analyzed from a subset of vaccinees to assess CMI responses using IFN-γ and granzyme B ELISPOT assays. Cytokine measurements were performed on PBMC supernatants after stimulation with H5N1 virus. Results PBMCs were available from 177 participants; 88 and 89 received 15-mcg and 90-mcg of unadjuvanted clade 2 vaccine, respectively. Following H5N1 clade 1 stimulation, IFN-γ but not granzyme B normalized spot-forming cell numbers had statistically significant increased numbers at each of the post-vaccination timepoints compared to baseline in pooled analyses of all vaccine doses and age groups. Clade 2 stimulation resulted in statistically significant increased numbers of IFN-γ cells only 180 days following the last vaccination. Responses were similar among younger and older study participants, as were responses among those primed with alum-adjuvanted or non-adjuvanted clade 1 H5N1 vaccines. The dosage of clade 2 vaccine did not impact CMI responses among primed subjects, but responses were statistically significantly greater in unprimed recipients of the 90-mcg dosage compared to unprimed recipients of the 15-mcg dosage. IFN-γ levels in the supernatants of stimulated PBMC were strongly correlated with IFN-γ ELISPOT results. Conclusion CMI responses occur in adults administered influenza A/H5N1 inactivated influenza vaccine.

Background Two major antigenically heterogenous norovirus genogroups (GI and GII) commonly infect humans and are the leading cause of foodborne, viral gastrointestinal infections in adults. Methods We assessed B cell responses in participants in a double-blind, placebo-controlled, dose-escalation phase 1 study of the safety and immunogenicity of an intramuscular bivalent norovirus virus-like particle (VLP) vaccine. The vaccine contained a GI.1 VLP (Norwalk) and a consensus GII.4 VLP, representing the two major genotypes that cause human disease, and was administered on days 0 and 28 to healthy adults aged 18–49 years. Four separate cohorts received increasing doses of 5 μg, 15 μg, 50 μg, and 150 μg of each VLP adjuvanted in monophosphoryl lipid A and alum. PBMCs were analyzed for B cell activation and mucosal homing markers (flow cytometry) and VLP-specific and total IgG and IgA Ab-secreting cells (ASCs); and serum titers of VLP-specific IgG, IgA, and Pan-Ig were determined. Results The vaccine elicited CD27+ CD38+ plasmablasts and high frequencies of ASCs specific for both VLP antigens in the peripheral blood at 7 days after the first dose. The plasmablasts exhibited a mucosal-homing phenotype and included a high proportion of IgA ASCs. Serum antibodies increased as early as 7 days after the first immunization. Conclusions The data suggest that a single dose of the IM bivalent norovirus vaccine is effective in activating pre-existing B cell memory. The rapid B cell response and the mucosal homing phenotype of induced ASCs are consistent with anamnestic responses in subjects primed by prior oral norovirus infection. This study is registered at ClinicalTrials.gov Identifier NCT01609257 .

During the 2009 influenza pandemic both seasonal and 2009 pandemic vaccines were recommended. We conducted a randomized trial of monovalent 2009-H1N1 vaccine and seasonal trivalent inactivated influenza vaccine (IIV3) given sequentially or concurrently to adults.Adults randomized to 4 study groups and stratified by age (18-64 and ≥65 years) received 1 dose of seasonal IIV3 or placebo and 2 doses of 2009-H1N1 vaccine or placebo in one of 4 combinations, i.e., H1N1+Placebo/H1N1+Placebo/IIV3 (HP/HP/V3), H1N1+IIV3/H1N1+Placebo/Placebo (HV3/HP/P), H1N1+Placebo/H1N1+IIV3/Placebo (HP/HV3/P), and IIV3+Placebo/H1N1+Placebo/H1N1 (V3P/HP/H). Intramuscular injections were given three times at 21 day intervals. Sera for antibody assays were obtained prior to and 21 days after each vaccination. Reactogenicity and adverse events were monitored.Eight hundred-five (805) adults were enrolled. All combinations of vaccines were safe and well tolerated. In general, one dose of 2009-H1N1 and one dose of IIV3, regardless of sequence or concurrency of administration, were immunogenic in adults. There were no significant differences in geometric mean titers (GMT) or the proportions of subjects with ≥4-fold rise in antibody responses and titers ≥40 for any vaccine group or between age strata for 2009-H1N1 after the first or second dose, although the vaccine sequence affected the titers to the IIV3 antigens. Hemagglutination inhibition antibody (HAI) GMTs against 2009-H1N1 for the combined age strata 21 days after the first 2009-H1N1 dose were 190.4, 182.1, 232.9 and 157.5 for HP/HP/V3, HV3/HP/P, HP/HV3/P and V3P/HP/H, respectively. While IIV3 GMTs were adequate they were generally lower than the 2009-H1N1 GMTs. In a subset of subjects, there was good correlation between HAI and microneutralization (MN) titers (Spearman's correlation coefficient 0.92).All vaccine combinations were generally well tolerated. Immune responses to one dose of 2009-H1N1 were adequate regardless of the sequence of vaccination in all age groups, but the sequence affected titers to IIV3 antigens.

A critical event in the life cycle of a virus is its initial attachment to host cells. This involves recognition by the viruses of specific receptors on the cell surface, including glycans. Viruses typically exhibit strain-dependent variations in recognizing specific glycan receptors, a feature that contributes significantly to cell tropism, host specificity, host adaptation and interspecies transmission. Examples include influenza viruses, noroviruses, rotaviruses, and parvoviruses. Both rotaviruses and noroviruses are well known gastroenteric pathogens that are of significant global health concern. While rotaviruses, in the family Reoviridae, are the major causative agents of life-threatening diarrhea in children, noroviruses, which belong to the Caliciviridae family, cause epidemic and sporadic cases of acute gastroenteritis across all age groups. Both exhibit enormous genotypic and serotypic diversity. Consistent with this diversity each exhibits strain-dependent variations in the types of glycans they recognize for cell attachment. This chapter reviews the current status of the structural biology of such strain-dependent glycan specificities in these two families of viruses.

Shellfish are known as vectors for human pathogens and despite regulation based on enteric bacteria they are still implicated in viral outbreaks. Among shellfish, oysters are the most common vector of contamination and the pathogens most frequently involved in these outbreaks are noroviruses, responsible for acute gastroenteritis in humans. Analysis of shellfish related outbreak data worldwide show an unexpected high proportion of NoV GI strains. Recent studies performed in vitro, in vivo and in the environment indicate that oysters are not just passive filter, but can selectively accumulate norovirus strains based on virus carbohydrate ligands shared with humans. These observations contribute to explain the GI/GII bias observed in shellfish-related outbreaks compared to other outbreaks.

Avian influenza A/H9N2 viruses can infect people and are viruses considered to be a potential pandemic threat. Prior studies with an inactivated G1 clade H9N2 vaccine reported that persons born before 1968 were more likely to have an immune response than younger subjects. We performed a randomized, double-blind trial to evaluate whether immune responses following immunization with an inactivated, unadjuvanted influenza G9 H9N2 vaccine prepared from A/chicken/Hong Kong/G9/97 virus were more frequent in persons born in 1964 or earlier (44–59 years) than in those born in 1970 or later (18–38 years). One hundred twenty one persons were randomized to receive two doses of either 7.5- or 30-mcg of hemagglutinin intramuscularly. Post-vaccination serum antibody responses as measured by hemagglutination inhibition and microneutralization were either similar in the two age cohorts or greater in the younger age group. Persons born before 1968 were not more likely to respond to a G9 H9N2 influenza vaccine than persons born in 1970 or later.

In a phase I clinical trial, one hundred healthy young adults were randomized to receive two doses 28 days apart of an inactivated, subvirion vaccine containing 15 or 45microg of influenza A/H5N1 hemagglutinin (HA) by the intramuscular (IM) route, or 3 or 9microg of H5 HA by the intradermal(ID) route. Seventy-seven subjects received a third dose. All regimens were safe and well tolerated. Antibody responses after two or three doses were low (or=20% oror=38%, respectively) and similar in groups given 3 or 9microg ID or 15microg IM, and were significantly lower than those given 45microg IM. Higher dosages of H5 HA and/or inclusion of adjuvant will be required to enhance immunogenicity by the ID route.

Antibody to the neuraminidase (NA) antigen of influenza viruses has been shown to correlate with immunity to influenza in humans and animal models. In a previous report, we showed that an inactivated influenza vaccine containing 60microg of the hemagglutinin (HA) of each strain induced significantly more serum anti-HA antibody among elderly persons than did the standard vaccine containing 15microg of the HA of each component. We developed a lectin-based assay for anti-NA antibody and used it to measure anti-NA antibody responses among subjects who had participated in that study. The high dosage vaccine contained eight times as much NA activity as the standard vaccine and induced a significantly higher frequency of antibody responses and higher mean postvaccination anti-NA titers to the N1 and N2 of the A/H1N1 and A/H3N2 viruses in the vaccines than did the standard vaccine. Ensuring an increased antibody response to the NA antigen in inactivated influenza virus vaccines should increase the protection against influenza. An increased quantity of the NA antigen in the vaccine will ensure an increased response.

A total of 600 healthy adults > or =65 years were randomized to receive 2 vaccinations 1 month apart of a subvirion avian influenza A/H5N1 vaccine containing 3.75, 7.5, 15, or 45microg of hemagglutinin (HA) with or without aluminum hydroxide (AlOH). All formulations were safe. Groups given the vaccine with AlOH had more injection site discomfort. Dose-related increases in antibody responses were noted after the second vaccination. Antibody responses to the vaccine were not enhanced by AlOH at any HA dose level. A microneutralization titer > or =40 was observed in 36% and 40% of subjects who received 45microg of HA with or without AlOH, respectively.

Summary Objectives Hematogenous vertebral osteomyelitis is caused predominantly by Staphylococcus aureus . The rise in incidence of methicillin-resistant S. aureus (MRSA) has complicated the treatment of this infection. Our objective was to evaluate therapeutic outcomes for S. aureus vertebral osteomyelitis in a setting of high MRSA prevalence. Methods We conducted a retrospective chart review of all patients who presented with S. aureus vertebral osteomyelitis over a 7-year period at 2 tertiary care hospitals in Houston, TX, USA. Results Thirty-five patients were identified who received ≥2-week course of parenteral antibiotics and had a follow-up period of at least 12 months post-therapy. MRSA was responsible for 20 (57%) cases. Mean duration of total antibiotic therapy was 61.4 days. The overall relapse rate was 14%. At 12 months post-therapy, 86% patients were cured. The one factor significantly associated with relapse was presence of undrained abscesses ( p =0.04). Conclusions When the mean duration of effective antibiotic therapy was 60 days, cure rates for S. aureus vertebral osteomyelitis exceeded 80%. Drainage of all associated abscesses correlated with a significantly higher rate of cure.

The ongoing epizootic of highly pathogenic influenza A/H5N1 viruses has ignited global efforts to develop human vaccines against these strains. Clinical trials of subunit H5 vaccines (recombinant hemagglutinin, subvirion, and purified surface antigen preparations) suggest that the high dosages of hemagglutinin are necessary to stimulate immune responses. Exciting results obtained using adjuvants (MF59 and others) and whole virus preparations point the way toward future vaccine development efforts. Other approaches (live attenuated vaccines, cell culture grown virus, DNA constructs, and conserved epitopes) are also being explored. Whether or not a pandemic spread of the A/H5N1 virus occurs, lessons learned as a result of these activities will better prepare us for future pandemics, as well as for interpandemic influenza.

Noroviruses are a major cause of sporadic cases and epidemic outbreaks of gastroenteritis. The development of molecular diagnostic assays has led to an increased recognition of the significance of these viruses as causes of gastroenteritis in all age groups. This article reviews the epidemiology, clinical manifestations and pathogenesis of norovirus infection, and it describes the diagnostic and therapeutic approaches to this disease.

Summary Objectives The purpose of the present study was to apply reverse transcription-PCR (RT-PCR) assays to clinical specimens collected from patients with acute respiratory illness and chronic obstructive pulmonary disease (COPD). Methods One hundred and ninety-four samples from two different study cohorts were analysed using RT-PCR assays for picornaviruses, coronaviruses 229E and OC43, influenza A and B viruses, respiratory syncytial virus, parainfluenza types 1–3 viruses, and human metapneumovirus and a PCR assay for adenoviruses. The results were added to results obtained previously using cell culture and serologic methods. Results RT-PCR assays identified an additional 35 respiratory virus-associated illnesses not identified previously by cell culture or serology ( n =46). Picornaviruses and coronaviruses were the most common viral infections identified only by RT-PCR. Overall, 41.8% of the acute respiratory illnesses evaluated were associated with a respiratory virus infection, with picornaviruses, coronaviruses and influenza viruses being the most common infections recognized. No human metapneumovirus infections were identified by RT-PCR assay. Conclusions Respiratory viral infections are commonly associated with acute respiratory illness in COPD patients, and the use of RT-PCR assays significantly increases the ability to diagnose these infections.

Objectives To analyze the underlying factors of mortality in elderly adults with bacteraemia. Methods The study included 238 episodes of bacteraemia in an urban public teaching hospital. Retrospective chart review recorded demographic information, comorbid conditions, length of stay, source of infection, and physiologic and laboratory data on admission. Results Of the 238 episodes of bacteraemia, 128 patients were 65–74 years of age and 110 patients were ≧75 years of age. Eighty-one percent came from home. Fifty-four percent had Gram positive cocci detected in blood cultures and 36% had Gram negative bacilli. Factors associated with increased odds of mortality included underlying renal disease, admission to MICU, hypotension and hypoalbuminemia. Decreased odds of mortality were associated with being admitted from home and receiving appropriate antibiotics. Conclusions Bacteraemia in the elderly has a high mortality rate, but is not significantly increased in those ≧75 years of age. The recent microbiology has shifted from Gram negative bacilli to Gram positive cocci. Physiologic abnormalities on admission predict worse outcomes in the elderly bacteraemic patient. Hypoalbuminemia on admission is associated with higher mortality rates in the elderly.

Real-time RT-PCR, combining amplification and detection of virus-specific amplicons, is a promising tool for norovirus detection in environmental or food samples such as shellfish. We developed a real-time RT-PCR assay based on one-step detection using single primer sets and probes for norovirus genogroups I and II. Seventy and seven RT-PCR units of genogroup I and II reference norovirus strains, respectively, were detected in artificially contaminated oysters. Validation of the new method on 150 archived naturally contaminated shellfish confirmed the utility of the genogroup II primer set to detect a large range of different strains circulating in France since 1995, but genogroup I strains were detected infrequently.

Noroviruses cause the majority of acute viral gastroenteritis cases that occur worldwide. The increased recognition of noroviruses as the cause of outbreaks and sporadic disease is due to the recent availability of improved norovirus-specific diagnostics. Transmission of these viruses is facilitated by their high prevalence in the community, shedding of infectious virus particles from asymptomatic individuals and the high stability of the virus in the environment. Currently, the spectrum of clinical disease and the understanding of host susceptibility factors are changing. Cases of chronic norovirus gastroenteritis have been observed in transplant recipients and unusual clinical presentations have been recognized in otherwise healthy adults that are under physical stress. Recently, noroviruses were found to bind to gut-expressed carbohydrates, leading to a correlation between a person's genetically determined carbohydrate expression and their susceptibility to Norwalk virus infection. Greater community surveillance and further investigation of carbohydrate receptor-binding properties could provide further insights into norovirus transmission, susceptibility and pathogenesis, and should aid in developing vaccines and antiviral therapies for this common viral disease.

Gastroenteritis outbreaks linked to shellfish consumption are numerous and Norwalk-like viruses (NLVs) are frequently the responsible causative agents. However, molecular data linking shellfish and clinical samples are still rare despite the availability of diagnostic methods. In a recent outbreak we found the same NLV sequence in stool and shellfish samples (100% identity over 313 bp in the capsid region), supporting the epidemiological data implicating the shellfish as the source of infection. A semiquantitative approach using most-probable-number-RT-PCR (MPN-RT-PCR) demonstrated the presence of a hundred of RT-PCR units per oyster. Follow-up of the oysters in the harvest area, for approximately 2 months, showed persistence of NLV contamination of the shellfish at levels up to a thousand RT-PCR units per oyster prior to depuration of the shellfish. This finding is useful in beginning to understand shellfish contamination and depuration for use in future hazard analyses.

The immunogenicity and safety of a chromatographically purified rabies vaccine (CPRV) was evaluated using US veterinary medical students. In the first study, 242 healthy adults were enrolled in a randomized, modified double-blind, multicenter trial and received five doses of either CPRV or human diploid cell vaccine (HDCV) by intramuscular injection on days 0, 3, 7, 14, and 28 concurrently with human rabies immunoglobulin in a simulated post-exposure prophylaxis regimen. Post-immunization titers in the CPRV and HDCV groups reached 0.5 IU/ml (the WHO-recommended minimally acceptable titer) or greater in all subjects in both vaccine groups by day 14 and remained above that level through day 90. In the second study, 438 healthy adults were enrolled in a randomized, double-blind, multicenter trial and assigned to receive five doses from one of three lots of CPRV by intramuscular injection on days 0, 3, 7, 14, and 28 in a simulated post-exposure prophylaxis regimen to evaluate lot consistency. Post-immunization titers rapidly increased to over 0.5 IU/ml by day 14 for all subjects and remained above that level through day 42 when the study was terminated. The three lots were considered equivalent. The percentage of subjects with at least one local reaction during the five-dose regimen was slightly lower in the CPRV group than in the HDCV group (P=0.06). The most frequently reported local reaction for all doses of vaccine was pain at the injection site. Headache, myalgia, and malaise were the most frequently reported systemic events. The percentage of subjects with at least one systemic event was significantly lower for CPRV (P=0.0084). No vaccine-related serious adverse reaction was reported in these studies. The results of these studies indicate that CPRV administered intramuscularly to healthy adults is immunogenic and is associated with fewer local and systemic reactions than HDCV.

Norwalk virus (NV) is the prototype human virus of the family Caliciviridae. A rapid immunomagnetic capture/reverse transcription-(IMC/RT-)PCR assay was developed for the detection of NV. Immunomagnetic capture (IMC) utilizes paramagnetic beads coupled to a virus-specific antibody and allows separation of virus from contaminating materials and virus concentration in a single step. The detection limit of the developed assay was approximately 250-750 genomic equivalents/ml of 10% stool suspension. The detection limit of the assay was not altered by the presence of excess hepatitis A virus (HAV), although non-specific binding of HAV to the paramagnetic beads was observed. A panel of 100 stools from experimental human infections was screened for NV using a previously described heat release method, an antigen ELISA, or IMC/RT-PCR. NV was detected in 65/100 of these samples by IMC/RT-PCR compared to only 38/99 by heat release and 31/95 by antigen detection ELISA. All samples that were negative by IMC were also negative by both heat release and antigen ELISA. The number of samples in which RT-PCR was inhibited was greatly reduced by the use of IMC/RT-PCR compared to the heat release method (1/100 and 16/95 samples inhibited, respectively). The ability of IMC to concentrate virus (> or =2000-fold greater than heat release) and effectively remove inhibitory substances gives this assay distinct advantages over both the heat release and antigen ELISAs.

Healthcare-associated diarrhea is an important nosocomial disease worldwide. The etiologic agent of healthcare-associated diarrhea is undefined in the majority of cases. Clostridium difficile (CD) is the only enteric pathogen regularly identified as a cause of healthcare-associated diarrhea, but is detected in only 15-20% of nosocomial diarrhea episodes. 1 Norovirus (NoV) gastroenteritis outbreaks in healthcare facilities have been well-documented.2, 3 However, the prevalence of sporadic NoV infections as a cause of healthcare-associated diarrhea in adults, in a non-epidemic setting, has not been established. With their environmental stability, resistance to most cleaning agents, and prolonged fecal excretion after clinical recovery,4 NoVs may play a role as a pathogen of healthcare-associated diarrhea. This study was designed to investigate the prevalence of sporadic NoV nosocomial diarrhea at a large tertiary university-based hospital in Houston, Texas. Stool specimens from hospitalized patients with healthcare-associated diarrhea from January to December 2007 were collected at St. Luke’s Episcopal Hospital (SLEH), a 627-bed tertiary university-based hospital. Stool samples were collected over one year to avoid possible overestimation biases related to isolated NoV outbreaks. No NoV outbreaks were noted at SLEH during this study period. Healthcare-associated diarrhea was defined as ≥3 unformed stools within a 24-hour period, with onset ≥ 72 hours after hospital admission or within 4 weeks after hospital discharge. Nosocomial diarrheal specimens testing negative for C. difficile by the direct cell culture cytotoxicity assay were included in this study. Patients who reported diarrhea < 72 hours after hospital admission or who were diagnosed with C. difficile infection (CDI) were excluded. This study was approved by the institutional review boards of the University of Texas Health Science Center at Houston and SLEH. NoV detection was performed by using both conventional and real-time polymerase chain reactions (rtPCR) to enhance the sensitivity of the evaluation for NoVs.5, 6 Stool samples were tested by the SLEH microbiology laboratory for CD toxin B by tissue culture cell cytotoxicity assay using a fibroblast cell line (Diagnostic Hybrids, Inc.) with antitoxin neutralization (Tech-Lab).7 Fecal specimens from 202 patients, who tested negative for CDI by cytotoxicity assay, were evaluated for this study. Ninety-three patients were excluded because they developed diarrhea 4 weeks after hospital discharge. Stool samples from 109 patients with healthcare-associated diarrhea were further investigated for the presence of NoV infection. A GI NoV strain was detected in 1 stool specimen from a patient suffering nosocomial diarrhea. GI NoV RNA in this patient’s stool specimen was confirmed by repeated conventional and rtPCR assays. No GII NoV strains were detected. The NoV-positive patient was a 27 year-old man, with a history of end-stage renal disease, congestive heart failure, and past CDI, who was admitted for a methicillin-resistant Staphylococcus aureus thigh abscess. The patient was receiving intravenous vancomycin for the abscess. Seven days after admission, the patient developed bloody diarrhea with fever up to 101°C and an elevated white blood cell count of 13,500/μL. C. difficile cytotoxicity assays were negative twice. An indium-111–labeled leukocyte scan, performed to investigate for metastatic S. aureus foci, demonstrated ascending, transverse, and descending colonic inflammation. A colonoscopy did not reveal any abnormalities. The diarrhea resolved after 5 days with no specific therapy. Healthcare-associated diarrhea is a significant cause of both morbidity and mortality and has been shown to prolong length of hospitalizations and increase medical costs.8 Despite advances in our understanding of CDI, little is known regarding the pathogenesis of nosocomial diarrhea, when C. difficile is excluded. This gastrointestinal disease likely represents a culmination of intestinal insults, leading to disruption of the normal intestinal microbiota. Factors contributing to the altered host intestinal microbiota include antibiotics, non-antimicrobial medications, chronic gastrointestinal disorders, medical procedures such as intra-abdominal surgeries, and other infectious processes.9 Other yet unidentified enteric pathogens may also contribute to the pathogenesis of healthcare-associated diarrhea. NoV outbreaks are increasingly being reported in healthcare institutions. However, in this epidemiologic survey for NoVs as a cause of sporadic nosocomial diarrhea at a tertiary university-based hospital, NoVs were detected in only 1 patient with CD-negative healthcare-associated diarrhea. This patient’s gastrointestinal illness developed in December 2007, during the peak season for NoV outbreaks in healthcare institutions,10 but the patient’s dysentery and pancolitis were atypical for NoV gastroenteritis. NoVs characteristically cause pathologic changes in the small intestinal tract, rather than the colon.11 This patient tested negative for CDI, but other undetected enteric pathogens such as Klebsiella oxytoca may have contributed to the hemorrhagic colitis. This patient may have been asymptomatically infected with NoVs; up to 33% of NoV infections have no clinical sequelae.12 Limitations of this study include the relatively small sample size and the study of a single center. C. difficile-positive stools were not evaluated for NoVs. As a result, mixed C. difficile and NoV infections may have been missed. It is possible that other regions of the world, where NoVs are endemic and outbreaks are more frequently reported, have higher prevalence rates of sporadic NoV healthcare-associated diarrhea. The pathogenesis of healthcare-associated diarrhea is poorly understood due to the complexity of interactions affecting the host intestinal microflora. NoVs are an important cause of healthcare-related epidemics, but appear to be an uncommon cause of sporadic healthcare-associated diarrhea at one tertiary university hospital in Houston, Texas. Further studies are needed to clarify the etiology and pathogenesis of this important gastrointestinal disease, in which traditional infectious enteropathogens may play little role.

We have previously demonstrated that about 70% of elderly persons exhibit deficient cytotoxic T lymphocyte (CD8+ CTL) responses against influenza viruses when compared to young persons. Since IFN-gamma, a Th1 cytokine and IL-4, a Th2 cytokine, stimulate and inhibit CD8+ CTL responses respectively, their role(s) in the age-related CTL deficiency was investigated. Lymphocytes from young adults (34 +/- 5 years old) and elderly subjects (71 +/- 1 years old) were stimulated in vitro with influenza A/H3N2, A/H1N1 or influenza B virus for 6-7 days. The CD8+ CTL activity against virus-infected autologous target cells was significantly lower among the elderly than the young subjects (P < 0.01). Following stimulation with influenza virus, IL-4 production in both age groups was similar on day 3 but significantly higher among elderly persons on day 6 (P < 0.05). In contrast, T cells from the elderly produced significantly lower IFN-gamma than did those from young persons on both days (P < 0.05). Treatment of T cells from young and elderly adults with recombinant human IL-12, a pivotal cytokine that stimulates Th1 cytokines, resulted in enhancement of CD8+ CTL activity and IFN-gamma production in a dose dependent manner (P < 0.01). IL-12-dependent enhancement of CTL activity was not always abrogated by anti-IFN-gamma antibody treatment. These results suggest that deficient influenza virus-specific CTL activity among the elderly is attributable to a Th1 to Th2 cytokine production switch. Immunotherapy with IL-12 could represent a useful approach to correct the CD8+ CTL deficiency and cytokine imbalance among elderly humans.

The authors set out to evaluate the use of the autopsy in an urban public teaching hospital setting during the AIDS era. Demographic and length of hospital stay data were obtained from weekly mortality review reports on all patients dying on the medicine service between 1/1/92 and 12/31/93. Clinical and autopsy diagnoses were compared for those patients who had autopsies. The autopsy rate was 16% (152/974). Significant, unsuspected diagnoses were found in 35% (53/152) of the cases, with infections, pulmonary emboli, and myocardial infarctions being most common. Human immunodeficiency virus-infected patients had a greater percentage of unsuspected findings (55%, 23/42), and many of these also were from an infectious etiology. The authors conclude that valuable, unsuspected information frequently can be obtained from autopsies in this clinical setting.

Background Tobacco-related lung diseases, including chronic obstructive pulmonary disease (COPD), are major causes of lung-related disability and death worldwide. Acute exacerbation of COPD (AE-COPD) is commonly associated with upper and lower respiratory tract viral infections and can result in respiratory failure in those with advanced lung disease. Objective We sought to determine the mechanism underlying COPD exacerbation and host response to pathogen-derived factors. Methods Over a 24-month period, we assessed the viral causes for upper and lower respiratory tract infections in patients with COPD (n = 155) and control subjects (n = 103). We collected nasal and bronchoalveolar lavage fluid and peripheral blood under baseline and exacerbated conditions. We determined the effect of human rhinovirus (HRV) proteinases on T-cell activation in human subjects and mice. Results HRVs are isolated from nasal and lung fluid from subjects with AE-COPD. Bronchoalveolar lavage fluid and CD4 T cells from patients with COPD exhibited a T H 1 and T H 2 cell cytokine phenotype during acute infection. HRV-encoded proteinase 2A activated monocyte-derived dendritic cells in vitro and induced strong T H 1 and T H 2 immune responses from CD4 T cells. Intranasal administration of recombinant rhinovirus proteinase 2A in mice resulted in an increase in airway hyperreactivity, lung inflammation, and IL-4 and IFN-γ production from CD4 T cells. Conclusion Our findings suggest that patients with severe COPD show T H 1- and T H 2-biased responses during AE-COPD. HRV-encoded proteinase 2A, like other microbial proteinases, could provide a T H 1- and T H 2-biasing adjuvant factor during upper and lower respiratory tract infection in patients with severe COPD. Alteration of the immune response to secreted viral proteinases might contribute to worsening of dyspnea and respiratory failure in patients with COPD.