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Background Coronavirus disease 2019 (COVID-19) vaccination coverage remains lower in communities with higher social vulnerability. Factors such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure risk and access to healthcare are often correlated with social vulnerability and may therefore contribute to a relationship between vulnerability and observed vaccine effectiveness (VE). Understanding whether these factors impact VE could contribute to our understanding of real-world VE. Methods We used electronic health record data from 7 health systems to assess vaccination coverage among patients with medically attended COVID-19-like illness. We then used a test-negative design to assess VE for 2- and 3-dose messenger RNA (mRNA) adult (≥18 years) vaccine recipients across Social Vulnerability Index (SVI) quartiles. SVI rankings were determined by geocoding patient addresses to census tracts; rankings were grouped into quartiles for analysis. Results In July 2021, primary series vaccination coverage was higher in the least vulnerable quartile than in the most vulnerable quartile (56% vs 36%, respectively). In February 2022, booster dose coverage among persons who had completed a primary series was higher in the least vulnerable quartile than in the most vulnerable quartile (43% vs 30%). VE among 2-dose and 3-dose recipients during the Delta and Omicron BA.1 periods of predominance was similar across SVI quartiles. Conclusions COVID-19 vaccination coverage varied substantially by SVI. Differences in VE estimates by SVI were minimal across groups after adjusting for baseline patient factors. However, lower vaccination coverage among more socially vulnerable groups means that the burden of illness is still disproportionately borne by the most socially vulnerable populations.

Background We assessed coronavirus disease 2019 (COVID-19) vaccination impact on illness severity among adults hospitalized with COVID-19, August 2021–March 2022. Methods We evaluated differences in intensive care unit (ICU) admission, in-hospital death, and length of stay among vaccinated (2 or 3 mRNA vaccine doses) versus unvaccinated patients aged ≥18 years hospitalized for ≥24 hours with COVID-19–like illness and positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) molecular testing. We calculated odds ratios (ORs) for ICU admission and death and subdistribution hazard ratios (SHR) for time to hospital discharge adjusted for age, geographic region, calendar time, and local virus circulation. Results We included 27 149 SARS-CoV-2–positive hospitalizations. During both Delta- and Omicron-predominant periods, protection against ICU admission was strongest among 3-dose vaccinees compared with unvaccinated patients (Delta OR, 0.52 [95% CI, .28–.96]; Omicron OR, 0.69 [95% CI, .54–.87]). During both periods, risk of in-hospital death was lower among vaccinated compared with unvaccinated patients but ORs overlapped across vaccination strata. We observed SHR >1 across all vaccination strata in both periods indicating faster discharge for vaccinated patients. Conclusions COVID-19 vaccination was associated with lower rates of ICU admission and in-hospital death in both Delta and Omicron periods compared with being unvaccinated.

The Omicron variant (B.1.1.529) of SARS-CoV-2, the virus that causes COVID-19, was first identified in the United States in November 2021, with the BA.1 sublineage (including BA.1.1) causing the largest surge in COVID-19 cases to date. Omicron sublineages BA.2 and BA.2.12.1 emerged later and by late April 2022, accounted for most cases.* Estimates of COVID-19 vaccine effectiveness (VE) can be reduced by newly emerging variants or sublineages that evade vaccine-induced immunity (1), protection from previous SARS-CoV-2 infection in unvaccinated persons (2), or increasing time since vaccination (3). Real-world data comparing VE during the periods when the BA.1 and BA.2/BA.2.12.1 predominated (BA.1 period and BA.2/BA.2.12.1 period, respectively) are limited. The VISION network

Influenza vaccines can mitigate illness severity, including reduced risk of ICU admission and death, in people with breakthrough infection. Less is known about vaccine attenuation of mild/moderate influenza illness. We compared subjective severity scores in vaccinated and unvaccinated persons with medically attended illness and laboratory-confirmed influenza. Participants were prospectively recruited when presenting for care at five US sites over nine seasons. Participants aged ≥ 16 years completed the EQ-5D-5L visual analog scale (VAS) at enrollment. After controlling for potential confounders in a multivariable model, including age and general health status, VAS scores were significantly higher among 2,830 vaccinated participants compared with 3,459 unvaccinated participants, indicating vaccinated participants felt better at the time of presentation for care. No differences in VAS scores were observed by the type of vaccine received among persons aged ≥ 65 years. Our findings suggest vaccine-associated attenuation of milder influenza illness is possible.

OBJECTIVES We assessed BNT162b2 vaccine effectiveness (VE) against mild to moderate and severe coronavirus disease 2019 (COVID-19) in children and adolescents through the Omicron BA.4/BA.5 period. METHODS Using VISION Network records from April 2021 to September 2022, we conducted a test-negative, case-control study assessing VE against COVID-19-associated emergency department/urgent care (ED/UC) encounters and hospitalizations using logistic regression, conditioned on month and site, adjusted for covariates. RESULTS We compared 9800 ED/UC cases with 70 232 controls, and 305 hospitalized cases with 2612 controls. During Delta, 2-dose VE against ED/UC encounters at 12 to 15 years was initially 93% (95% confidence interval 89 to 95), waning to 77% (69% to 84%) after ≥150 days. At ages 16 to 17, VE was initially 93% (86% to 97%), waning to 72% (63% to 79%) after ≥150 days. During Omicron, VE at ages 12 to 15 was initially 64% (44% to 77%), waning to 13% (3% to 23%) after ≥150 days; at ages 16 to 17 VE was 31% (10% to 47%) during days 60 to 149, waning to 7% (−8 to 20%) after 150 days. A monovalent booster increased VE to 54% (40% to 65%) at ages 12 to 15 and 46% (30% to 58%) at ages 16 to 17. At ages 5 to 11, 2-dose VE was 49% (33% to 61%) initially and 41% (29% to 51%) after 150 days. During Delta, VE against hospitalizations at ages 12 to 17 was high (>97%), and at ages 16 to 17 remained 98% (73% to 100%) beyond 150 days; during Omicron, hospitalizations were too infrequent to precisely estimate VE. CONCLUSIONS BNT162b2 protected children and adolescents against mild to moderate and severe COVID-19. VE was lower during Omicron predominance including BA.4/BA.5, waned after dose 2 but increased after a monovalent booster. Children and adolescents should receive all recommended COVID-19 vaccinations.

CDC recommends that all persons aged ≥18 years receive a single COVID-19 vaccine booster dose ≥2 months after receipt of an Ad.26.COV2.S (Janssen [JohnsonJohnson]) adenovirus vector-based primary series vaccine; a heterologous COVID-19 mRNA vaccine is preferred over a homologous (matching) Janssen vaccine for booster vaccination. This recommendation was made in light of the risks for rare but serious adverse events following receipt of a Janssen vaccine, including thrombosis with thrombocytopenia syndrome and Guillain-Barré syndrome

Previous infection with SARS-CoV-2 (the virus that causes COVID-19) or COVID-19 vaccination can provide immunity and protection from subsequent SARS-CoV-2 infection and illness. CDC used data from the VISION Network* to examine hospitalizations in adults with COVID-19-like illness and compared the odds of receiving a positive SARS-CoV-2 test result, and thus having laboratory-confirmed COVID-19, between unvaccinated patients with a previous SARS-CoV-2 infection occurring 90-179 days before COVID-19-like illness hospitalization, and patients who were fully vaccinated with an mRNA COVID-19 vaccine 90-179 days before hospitalization with no previous documented SARS-CoV-2 infection. Hospitalized adults aged ≥18 years with COVID-19-like illness were included if they had received testing at least twice: once associated with a COVID-19-like illness hospitalization during January-September 2021 and at least once earlier (since February 1, 2020, and ≥14 days before that hospitalization). Among COVID-19-like illness hospitalizations in persons whose previous infection or vaccination occurred 90-179 days earlier, the odds of laboratory-confirmed COVID-19 (adjusted for sociodemographic and health characteristics) among unvaccinated, previously infected adults were higher than the odds among fully vaccinated recipients of an mRNA COVID-19 vaccine with no previous documented infection (adjusted odds ratio [aOR] = 5.49; 95% confidence interval [CI] = 2.75-10.99). These findings suggest that among hospitalized adults with COVID-19-like illness whose previous infection or vaccination occurred 90-179 days earlier, vaccine-induced immunity was more protective than infection-induced immunity against laboratory-confirmed COVID-19. All eligible persons should be vaccinated against COVID-19 as soon as possible, including unvaccinated persons previously infected with SARS-CoV-2.

COVID-19 vaccination coverage remains lower in communities with higher social vulnerability. Factors such as SARS-CoV-2 exposure risk and access to health care are often correlated with social vulnerability and may therefore contribute to a relationship between vulnerability and observed vaccine effectiveness (VE). Understanding whether these factors impact VE could contribute to our understanding of real-world VE.We used electronic health record data from seven health systems to assess vaccination coverage among patients with medically attended COVID-19-like illness. We then used a test-negative design to assess VE for 2- and 3-dose mRNA adult (≥18 years) vaccine recipients across Social Vulnerability Index (SVI) quartiles. SVI rankings were determined by geocoding patient addresses to census tracts; rankings were grouped into quartiles for analysis.In July 2021, primary series vaccination coverage was higher in the least vulnerable quartile than in the most vulnerable quartile (56% vs. 36%, respectively). In February 2022, booster dose coverage among persons who had completed a primary series was higher in the least vulnerable quartile than in the most vulnerable quartile (43% vs. 30%). VE among 2-dose and 3-dose recipients during the Delta and Omicron BA.1 periods of predominance was similar across SVI quartiles.COVID-19 vaccination coverage varied substantially by SVI. Differences in VE estimates by SVI were minimal across groups after adjusting for baseline patient factors. However, lower vaccination coverage among more socially vulnerable groups means that the burden of illness is still disproportionately borne by the most socially vulnerable populations.

Persons with moderate-to-severe immunocompromising conditions might have reduced protection after COVID-19 vaccination, compared with persons without immunocompromising conditions (1-3). On August 13, 2021, the Advisory Committee on Immunization Practices (ACIP) recommended that adults with immunocompromising conditions receive an expanded primary series of 3 doses of an mRNA COVID-19 vaccine. ACIP followed with recommendations on September 23, 2021, for a fourth (booster) dose and on September 1, 2022, for a new bivalent mRNA COVID-19 vaccine booster dose, containing components of the BA.4 and BA.5 sublineages of the Omicron (B.1.1.529) variant (4). Data on vaccine effectiveness (VE) of monovalent COVID-19 vaccines among persons with immunocompromising conditions since the emergence of the Omicron variant in December 2021 are limited. In the multistate VISION Network

ImportanceRecent sublineages of the SARS-CoV-2 Omicron variant, including BA.4 and BA.5, may be associated with greater immune evasion and less protection against COVID-19 following vaccination.ObjectiveTo evaluate the association between COVID-19 mRNA vaccination with 2, 3, or 4 doses among immunocompetent adults and the risk of medically attended COVID-19 illness during a period of BA.4/BA.5 predominant circulation; to evaluate the relative severity of COVID-19 in hospitalized cases across Omicron BA.1, BA.2/BA.2.12.1, and BA.4/BA.5 sublineage periods.Setting, Design and ParticipantsTest-negative study of adults with COVID-19-like illness (CLI) and molecular testing for SARS-CoV-2 conducted in 10 states from December 16, 2021, to August 20, 2022.ExposuremRNA COVID-19 vaccination.Main Outcomes and MeasuresEmergency department/urgent care encounters, hospitalizations, and admission to the intensive care unit (ICU) or in-hospital death. The adjusted odds ratio (OR) for the association between prior vaccination and medically attended COVID-19 was used to estimate VE, stratified by care setting and vaccine doses (2, 3, or 4 doses vs 0 doses as reference group). Among hospitalized case-patients, demographic and clinical characteristics and in-hospital outcomes including ICU admission and death were compared across sublineage periods.ResultsBetween June 19 – August 20, 2022, 82,229 ED/UC and 21,007 hospital encounters were included for the BA.4/BA.5 vaccine effectiveness analysis. Among adults hospitalized with CLI, the adjusted odds ratio (OR) was 0.75 (95% CI: 0.68-0.83) for receipt of 2 vaccine doses at ≥150 days after receipt, 0.32 (95% CI: 0.20-0.50) for a third dose 7-119 days after receipt, and 0.64 (95% CI: 0.58-0.71) for a third dose ≥120 days (median 235 days) after receipt for cases vs controls. For COVID-19-associated hospitalization, among patients ages ≥65 years 7-59 and ≥60 days (median 88 days) after a fourth dose, ORs were 0.34 (95% CI: 0.25-0.47) and 0.43 (95% CI: 0.34-0.56), respectively. Among hospitalized cases, ICU admission and/or in-hospital death occurred in 21.4% during the BA.1 vs 14.7% during the BA.4/BA.5 period (standardized mean difference: 0.17).ConclusionVE against medically attended COVID-19 illness decreased over time since last dose; receipt of one or two booster doses increased effectiveness over a primary series alone.KEY POINTSQuestionWhat is the association between receipt of first-generation COVID-19 mRNA vaccines and medically attended COVID-19 during Omicron BA.4/BA.5 sublineage predominance?FindingsThis test-negative analysis included 82,229 emergency department or urgent care encounters and 21,007 hospitalizations for COVID-19-like illness. Among hospitalized patients, the likelihood of recent vaccination (7-119 days) with 3 mRNA vaccine doses (vs unvaccinated) was significantly lower (odds ratio, 0.32) in cases than SARS-CoV-2-negative controls, but with lower associated protection ≥120 days post-vaccination (odds ratio, 0.64).MeaningFirst-generation COVID-19 vaccines were associated with protection against COVID-19 during the Omicron BA.4/BA.5 sublineage-predominant periods but this declined over time.

Objective To estimate the effectiveness of mRNA vaccines against moderate and severe covid-19 in adults by time since second, third, or fourth doses, and by age and immunocompromised status. Design Test negative case-control study. Setting Hospitals, emergency departments, and urgent care clinics in 10 US states, 17 January 2021 to 12 July 2022. Participants 893 461 adults (≥18 years) admitted to one of 261 hospitals or to one of 272 emergency department or 119 urgent care centers for covid-like illness tested for SARS-CoV-2. Main outcome measures The main outcome was waning of vaccine effectiveness with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine during the omicron and delta periods, and the period before delta was dominant using logistic regression conditioned on calendar week and geographic area while adjusting for age, race, ethnicity, local virus circulation, immunocompromised status, and likelihood of being vaccinated. Results 45 903 people admitted to hospital with covid-19 (cases) were compared with 213 103 people with covid-like illness who tested negative for SARS-CoV-2 (controls), and 103 287 people admitted to emergency department or urgent care with covid-19 (cases) were compared with 531 168 people with covid-like illness who tested negative for SARS-CoV-2. In the omicron period, vaccine effectiveness against covid-19 requiring admission to hospital was 89% (95% confidence interval 88% to 90%) within two months after dose 3 but waned to 66% (63% to 68%) by four to five months. Vaccine effectiveness of three doses against emergency department or urgent care visits was 83% (82% to 84%) initially but waned to 46% (44% to 49%) by four to five months. Waning was evident in all subgroups, including young adults and individuals who were not immunocompromised; although waning was morein people who were immunocompromised. Vaccine effectiveness increased among most groups after a fourth dose in whom this booster was recommended. Conclusions Effectiveness of mRNA vaccines against moderate and severe covid-19 waned with time after vaccination. The findings support recommendations for a booster dose after a primary series and consideration of additional booster doses.

BackgroundEvidence for vaccine effectiveness (VE) against influenza-associated pneumonia has varied by season, location, and strain. We estimate VE against hospitalization for radiographically identified influenza-associated pneumonia during 2015–2016 to 2017–2018 seasons in the US Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN).MethodsAmong adults aged ≥18 years admitted to 10 US hospitals for acute respiratory illness (ARI), clinician-investigators used keywords from reports of chest imaging performed during 3 days around hospital admission to assign a diagnosis of “definite/probable pneumonia.” We used a test-negative design to estimate VE against hospitalization for radiographically identified laboratory-confirmed influenza-associated pneumonia, comparing reverse transcriptase–polymerase chain reaction–confirmed influenza cases with test-negative subjects. Influenza vaccination status was documented in immunization records or self-reported, including date and location. Multivariable logistic regression models were used to adjust for age, site, season, calendar-time, and other factors.ResultsOf 4843 adults hospitalized with ARI included in the primary analysis, 266 (5.5%) had “definite/probable pneumonia” and confirmed influenza. Adjusted VE against hospitalization for any radiographically confirmed influenza-associated pneumonia was 38% (95% confidence interval [CI], 17–53%); by type/subtype, it was 74% (95% CI, 52–87%) influenza A (H1N1)pdm09, 25% (95% CI, −15% to 50%) A (H3N2), and 23% (95% CI, −32% to 54%) influenza B. Adjusted VE against intensive care for any influenza was 57% (95% CI, 19–77%).ConclusionsInfluenza vaccination was modestly effective among adults in preventing hospitalizations and the need for intensive care associated with influenza pneumonia. VE was significantly higher against A (H1N1)pdm09 and was low against A (H3N2) and B.

Introduction Mid-season influenza vaccine effectiveness (VE) estimates are a useful tool to help guide annual influenza vaccine strain selection, vaccine policy, and public health messaging. We propose using a sample size-driven approach with data-driven inputs for publication of mid-season influenza VE. Methods We used pooled inputs for VE by (sub)type and average vaccine coverage by age groups using data from eight seasons of the US Influenza VE Network to calculate sample sizes needed to estimate mid-season VE. Results We estimate that 135 influenza-positive cases would be needed to detect an overall VE of 40% with 55% vaccine coverage among test-negative controls. Larger sample sizes would be required to produce reliable estimates specifically against influenza A/H3N2 and for older age groups. Conclusion Using an existing network, most of the recent influenza seasons in the US would facilitate valid mid-season VE estimates using the proposed sample sizes for broad age groupings.

We assessed COVID-19 vaccination impact on illness severity among adults hospitalized with COVID-19 August 2021-March 2022.We evaluated differences in intensive care unit (ICU) admission, in-hospital death, and length of stay among vaccinated (2 or 3 mRNA vaccine doses) versus unvaccinated patients aged ≥18 years hospitalized for ≥24 hours with COVID-19-like illness (CLI) and positive SARS-CoV-2 molecular testing. We calculated odds ratios for ICU admission and death and subdistribution hazard ratios (SHR) for time to hospital discharge adjusted for age, geographic region, calendar time, and local virus circulation.We included 27,149 SARS-CoV-2 positive hospitalizations. During both Delta and Omicron-predominant periods, protection against ICU admission was strongest among 3-dose vaccinees compared with unvaccinated patients (Delta OR [CI]: 0.52 [0.28-0.96]); Omicron OR [CI]: 0.69 [0.54-0.87]). During both periods, risk of in-hospital of death was lower among vaccinated compared with unvaccinated but ORs were overlapping; during Omicron, lowest among 3-dose vaccinees (OR [CI] 0.39 [0.28-0.54]). We observed SHR1 across all vaccination strata in both periods indicating faster discharge for vaccinated patients.COVID-19 vaccination was associated with lower rates of ICU admission and in-hospital death in both Delta and Omicron periods compared with being unvaccinated.

Epidemics of seasonal influenza vary in intensity annually, and influenza vaccine effectiveness (VE) fluctuates based in part on antigenic match to circulating viruses. We estimated the incidence of influenza and influenza cases averted by vaccination in four ambulatory care sites in the United States, during seasons when overall influenza VE ranged from 29% to 40%.We conducted active surveillance for influenza at ambulatory care settings at four sites within the United States Influenza Vaccine Effectiveness Network. We extrapolated the total number of influenza cases in the source populations served by these organizations based on incidence of medically attended acute respiratory illness in the source population and influenza test results in those actively tested for influenza. We estimated the number of medically attended influenza cases averted based on incidence, vaccine coverage, and VE.From 2016/17 through 2018/19, incidence of ambulatory visits for laboratory-confirmed influenza ranged from 31 to 51 per 1,000 population. Incidence was highest in children aged 9-17 years (range, 56 to 81 per 1,000) and lowest in adults aged 18-49 years (range, 23-32 per 1,000). Medically attended cases averted by vaccination ranged from a high of 46.6 (95 % CI, 12.1- 91.9) per 1,000 vaccinees in children aged 6 months to 8 years, to a low of 6.9 (95 % CI, -5.1- 27.3) per 1,000 vaccinees in adults aged ≥ 65 years.Even in seasons with low vaccine effectiveness for a particular virus subtype, influenza vaccines can still lead to clinically meaningful reductions in ambulatory care visits for influenza.

ImportanceRecent SARS-CoV-2 Omicron variant sublineages, including BA.4 and BA.5, may be associated with greater immune evasion and less protection against COVID-19 after vaccination.ObjectivesTo evaluate the estimated vaccine effectiveness (VE) of 2, 3, or 4 doses of COVID-19 mRNA vaccination among immunocompetent adults during a period of BA.4 or BA.5 predominant circulation; and to evaluate the relative severity of COVID-19 in hospitalized patients across Omicron BA.1, BA.2 or BA.2.12.1, and BA.4 or BA.5 sublineage periods.Design, Setting, and ParticipantsThis test-negative case-control study was conducted in 10 states with data from emergency department (ED) and urgent care (UC) encounters and hospitalizations from December 16, 2021, to August 20, 2022. Participants included adults with COVID-19–like illness and molecular testing for SARS-CoV-2. Data were analyzed from August 2 to September 21, 2022.ExposuresmRNA COVID-19 vaccination.Main Outcomes and MeasuresThe outcomes of interest were COVID-19 ED or UC encounters, hospitalizations, and admission to the intensive care unit (ICU) or in-hospital death. VE associated with protection against medically attended COVID-19 was estimated, stratified by care setting and vaccine doses (2, 3, or 4 doses vs 0 doses as the reference group). Among hospitalized patients with COVID-19, demographic and clinical characteristics and in-hospital outcomes were compared across sublineage periods.ResultsDuring the BA.4 and BA.5 predominant period, there were 82 229 eligible ED and UC encounters among patients with COVID-19–like illness (median [IQR] age, 51 [33-70] years; 49 682 [60.4%] female patients), and 19 114 patients (23.2%) had test results positive for SARS-CoV-2; among 21 007 hospitalized patients (median [IQR] age, 71 [58-81] years; 11 209 [53.4%] female patients), 3583 (17.1 %) had test results positive for SARS-CoV-2. Estimated VE against hospitalization was 25% (95% CI, 17%-32%) for receipt of 2 vaccine doses at 150 days or more after receipt, 68% (95% CI, 50%-80%) for a third dose 7 to 119 days after receipt, and 36% (95% CI, 29%-42%) for a third dose 120 days or more (median [IQR], 235 [204-262] days) after receipt. Among patients aged 65 years or older who had received a fourth vaccine dose, VE was 66% (95% CI, 53%-75%) at 7 to 59 days after vaccination and 57% (95% CI, 44%-66%) at 60 days or more (median [IQR], 88 [75-105] days) after vaccination. Among hospitalized patients with COVID-19, ICU admission or in-hospital death occurred in 21.4% of patients during the BA.1 period vs 14.7% during the BA.4 and BA.5 period (standardized mean difference: 0.17).Conclusions and RelevanceIn this case-control study of COVID-19 vaccines and illness, VE associated with protection against medically attended COVID-19 illness was lower with increasing time since last dose; estimated VE was higher after receipt of 1 or 2 booster doses compared with a primary series alone.

Background Influenza causes significant morbidity and mortality and stresses hospital resources during periods of increased circulation. We evaluated the effectiveness of the 2019–2020 influenza vaccine against influenza-associated hospitalization in the United States. Methods We included adults hospitalized with acute respiratory illness at 14 hospitals and tested for influenza viruses by reserve-transcription polymerase chain reaction. Vaccine effectiveness (VE) was estimated by comparing the odds of current-season influenza vaccination in test-positive influenza cases vs test-negative controls, adjusting for confounders. VE was stratified by age and major circulating influenza types along with A(H1N1)pdm09 genetic subgroups. Results A total of 3116 participants were included, including 18% (n = 553) influenza-positive cases. Median age was 63 years. Sixty-seven percent (n = 2079) received vaccination. Overall adjusted VE against influenza viruses was 41% (95% confidence interval [CI], 27%–52%). VE against A(H1N1)pdm09 viruses was 40% (95% CI, 24%–53%) and 33% against B viruses (95% CI, 0–56%). Of the 2 major A(H1N1)pdm09 subgroups (representing 90% of sequenced H1N1 viruses), VE against one group (5A + 187A,189E) was 59% (95% CI, 34%–75%) whereas no VE was observed against the other group (5A + 156K) (–1% [95% CI, –61% to 37%]). Conclusions In a primarily older population, influenza vaccination was associated with a 41% reduction in risk of hospitalized influenza illness.

We estimated vaccine effectiveness (VE) for prevention of influenza-associated hospitalizations among adults during the 2018–2019 influenza season. Adults admitted with acute respiratory illness to 14 hospitals of the US Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN) and testing positive for influenza were cases; patients testing negative were controls. VE was estimated using logistic regression and inverse probability of treatment weighting. We analyzed data from 2863 patients with a mean age of 63 years. Adjusted VE against influenza A(H1N1)pdm09–associated hospitalization was 51% (95% confidence interval [CI], 25%–68%). Adjusted VE against influenza A(H3N2) virus–associated hospitalization was −2% (95% CI, −65% to 37%) and differed significantly by age, with VE of −130% (95% CI, −374% to −27%) among adults 18 to ≤56 years of age. Although vaccination halved the risk of influenza A(H1N1)pdm09–associated hospitalizations, it conferred no protection against influenza A(H3N2)–associated hospitalizations. We observed negative VE for young and middle-aged adults but cannot exclude residual confounding as a potential explanation.

The incidence of pancreatic cancer is age dependent. Ninety percent of new diagnoses occur in patients older than 55 years. Despite the association with age and cancer, elderly patients are historically underrepresented in clinical trials. Thus, optimal management of elderly patients has a lack of data. The purpose of this retrospective study was to investigate the outcomes of palliative chemotherapy in elderly patients with pancreatic cancer compared with supportive care alone.Unicentric data were reviewed on all elderly patients (defined as age65 years) with a diagnosis of pancreatic cancer from 2008 through 2019 to compare outcomes in those who received chemotherapy versus supportive care alone.The study reviewed 665 patients with a median age of 75 years (mean, 75.7 years) and average Charlson Comorbidity Score of 5.74. Of them, 291 received chemotherapy and 363 received supportive care only. Chemotherapy was associated with a median overall survival of 250 versus 93 days with supportive care (P0.0001). Analysis showed improved survival for all age ranges, cancer stages, and Charlson Comorbidity Scores.Elderly pancreatic cancer patients can benefit from palliative chemotherapy, and it should be considered, especially in patients with fewer medical comorbidities and better functional status.

In the United States, annual vaccination against seasonal influenza is recommended for all persons aged ≥6 months (https://www.cdc.gov/flu/protect/whoshouldvax.htm). Effectiveness of seasonal influenza vaccine varies by season. During each influenza season since 2004-05, CDC has estimated the effectiveness of seasonal influenza vaccine to prevent laboratory-confirmed influenza associated with medically attended acute respiratory illness (ARI). This interim report uses data from 3,254 children and adults enrolled in the U.S. Influenza Vaccine Effectiveness Network (U.S. Flu VE Network) during November 23, 2018-February 2, 2019. During this period, overall adjusted vaccine effectiveness against all influenza virus infection associated with medically attended ARI was 47% (95% confidence interval [CI] = 34%-57%). For children aged 6 months-17 years, overall vaccine effectiveness was 61% (44%-73%). Seventy-four percent of influenza A infections for which subtype information was available were caused by A(H1N1)pdm09 viruses. Vaccine effectiveness was estimated to be 46% (30%-58%) against illness caused by influenza A(H1N1)pdm09 viruses. CDC recommends that health care providers continue to administer influenza vaccine because influenza activity is ongoing and the vaccine can still prevent illness, hospitalization, and death associated with currently circulating influenza viruses, or other influenza viruses that might circulate later in the season. During the 2017-18 influenza season, in which influenza A(H3N2) predominated, vaccination was estimated to prevent 7.1 million illnesses, 3.7 million medical visits, 109,000 hospitalizations, and 8,000 deaths (1). Vaccination can also reduce the severity of influenza-associated illness (2). Persons aged ≥6 months who have not yet been vaccinated this season should be vaccinated.

e24009 Background: Immunotherapy (IT) has cemented itself as a mainstay in cancer treatment, especially in those with late stage malignancies. Generally, these agents are well tolerated, but there is a known association with immune-related adverse events (iRAE). Due to an underrepresentation of elderly patients in clinical trial data, it is valuable to understand the tolerance of these agents. The primary objective of our study was to evaluate for an association between older age, defined as age 75 and above, and increased risk for iRAE in a real-world population. Methods: We performed a retrospective study utilizing data from elderly patients (pts) who had first received IT (specifically Pembrolizumab, Nivolumab, Atezolizumab, Avelumab, and Durvalumab) from 01/01/2015 through 12/31/2019. This subset of pts were followed until 12/31/2021. Descriptive analyses were performed to identify iRAE patterns. A chi-square test or a Fisher’s exact test was used to test for associations in bivariate comparisons while a two-sample t-test was used to test for differences in continuous variables between age groups > 75 to 79 years (Group 1) and > 80 years (Group 2). Statistical significance was determined by p < 0.05 unless otherwise noted. Results: 103 pts qualified for assessment over the study period. Group 1 had a total of 48 pts with a median age of 77. Group 2 had a total of 55 pts with a median age of 84. The study had 57 males and 46 females. 96 pts were Stage IV and 7 pts were Stage III. The most prevalent malignancies in the study were lung, skin, and renal cancer. Treatment intent was palliative for 96 pts, adjuvant for 6 pts, and neo-adjuvant for 1 pt. Overall, there were 72 pts with reported iRAE and 31 pts without reported iRAE. Of the pts with iRAE: 7 pts required outpatient observation without intervention, 38 pts required outpatient intervention(s), 19 pts were hospitalized, and 8 pts required ICU level of care. There was one death due to complications from encephalitis associated with hypophysitis and hyperthyroidism. Regarding discontinuation of IT for pts: 42 pts transitioned to hospice, 35 pts had progression of disease, 8 pts finished their treatment regimen, 5 pts developed an alternative diagnosis, and 9 pts discontinued due to iRAE. Nine pts in the study required corticosteroids for their iRAE. There was no statistically significant difference in incidence of any iRAE (regardless of type) between the two age groups 75-79 and over 80 years (p-value = 0.3703). Similarly, there was no difference for sub-categories including stage of cancer, type of cancer, treatment intent, and severity of iRAE. Conclusions: Elderly pts over age 75 that received the aforementioned IT were shown to have relatively tolerable safety profiles regardless of their age group and the majority continued with IT despite iRAE. This study reinforces the notion that IT could be used in geriatric pts without fear of exposing this vulnerable age group to substantial rates of negative outcomes.

ObjectivesTo ascertain parental perceptions of the impact of restricted visiting policies to neonatal intensive care units during the current COVID-19 pandemic.DesignCross-sectional survey of parents impacted by visitation policies.SettingSix tertiary level neonatal units, four from the UK and two from the USA, participated in the study.ParticipantsParents and families of infants hospitalised in the participating centres between 1 May 2020 and 21 August 2020.MethodsOnline-based and/or paper-based survey, querying the visitation policies and their impact on parents’ ability to visit, care for and bond with their infants.ResultsA total of 231 responses were received. Visitation limited to a single visitor with no restrictions on duration was the most frequently reported policy; 140/217 (63%). Visitation policies were perceived as being restrictive by 62% (138/219) of the respondents with 37% (80/216) reporting being able to visit less often than desired, 41% (78/191) reporting being unable to bond enough and 27% (51/191) reporting not being able to participate in their baby’s daily care. Mild to severe impact on breast feeding was reported by 36% (75/209) of respondents. Stricter policies had a higher impact on families and were significantly associated with a lack of bonding time, inability to participate in care and an adverse impact on breast feeding.ConclusionsVisitation policies during the COVID-19 pandemic varied between centres and over time with stricter restrictions implemented earlier on in the pandemic. Parents reported significant impacts on their ability to visit, care for and bond with their infants with perceived severity of impact worse with stricter restrictions.

Background Multivalent influenza vaccine products provide protection against influenza A(H1N1)pdm09, A(H3N2), and B lineage viruses. The 2018–2019 influenza season in the United States included prolonged circulation of A(H1N1)pdm09 viruses well-matched to the vaccine strain and A(H3N2) viruses, the majority of which were mismatched to the vaccine. We estimated the number of vaccine-prevented influenza-associated illnesses, medical visits, hospitalizations, and deaths for the season. Methods We used a mathematical model and Monte Carlo algorithm to estimate numbers and 95% uncertainty intervals (UIs) of influenza-associated outcomes prevented by vaccination in the United States. The model incorporated age-specific estimates of national 2018–2019 influenza vaccine coverage, influenza virus–specific vaccine effectiveness from the US Influenza Vaccine Effectiveness Network, and disease burden estimated from population-based rates of influenza-associated hospitalizations through the Influenza Hospitalization Surveillance Network. Results Influenza vaccination prevented an estimated 4.4 million (95%UI, 3.4 million–7.1 million) illnesses, 2.3 million (95%UI, 1.8 million–3.8 million) medical visits, 58 000 (95%UI, 30 000–156 000) hospitalizations, and 3500 (95%UI, 1000–13 000) deaths due to influenza viruses during the US 2018–2019 influenza season. Vaccination prevented 14% of projected hospitalizations associated with A(H1N1)pdm09 overall and 43% among children aged 6 months–4 years. Conclusions Influenza vaccination averted substantial influenza-associated disease including hospitalizations and deaths in the United States, primarily due to effectiveness against A(H1N1)pdm09. Our findings underscore the value of influenza vaccination, highlighting that vaccines measurably decrease illness and associated healthcare utilization even in a season in which a vaccine component does not match to a circulating virus.

Background Since 2013, quadrivalent influenza vaccines containing 2 B viruses gradually replaced trivalent vaccines in the United States. We compared the vaccine effectiveness of quadrivalent to trivalent inactivated vaccines (IIV4 to IIV3, respectively) against illness due to influenza B during the transition, when IIV4 use increased rapidly. Methods The US Influenza Vaccine Effectiveness (Flu VE) Network analyzed 25 019 of 42 600 outpatients aged ≥6 months who enrolled within 7 days of illness onset during 6 seasons from 2011–2012. Upper respiratory specimens were tested for the influenza virus type and B lineage. Using logistic regression, we estimated IIV4 or IIV3 effectiveness by comparing the odds of an influenza B infection overall and the odds of B lineage among vaccinated versus unvaccinated participants. Over 4 seasons from 2013–2014, we compared the relative odds of an influenza B infection among IIV4 versus IIV3 recipients. Results Trivalent vaccines included the predominantly circulating B lineage in 4 of 6 seasons. During 4 influenza seasons when both IIV4 and IIV3 were widely used, the overall effectiveness against any influenza B was 53% (95% confidence interval [CI], 45–59) for IIV4 versus 45% (95% CI, 34–54) for IIV3. IIV4 was more effective than IIV3 against the B lineage not included in IIV3, but comparative effectiveness against illnesses related to any influenza B favored neither vaccine valency. Conclusions The uptake of quadrivalent inactivated influenza vaccines was not associated with increased protection against any influenza B illness, despite the higher effectiveness of quadrivalent vaccines against the added B virus lineage. Public health impact and cost-benefit analyses are needed globally., During the 4 influenza seasons beginning in 2013–2014, trivalent and quadrivalent inactivated influenza vaccines provided equivalent protection against any influenza B illness in the United States, while quadrivalent vaccines provided better protection against the added B virus lineage.