Lack of Evidence for Vaccine-Associated Enhanced Disease From COVID-19 Vaccines Among Adults in the Vaccine Safety Datalink.

PURPOSE: Vaccine-associated enhanced disease (VAED) is a theoretical concern with new vaccines, although trials of authorized vaccines against SARS-CoV-2 have not identified markers for VAED. The purpose of this study was to detect any signals for VAED among adults vaccinated against coronavirus disease 2019 (COVID-19). METHODS: In this cross-sectional study, we assessed COVID-19 severity as a proxy for VAED among 400 adults hospitalized for COVID-19 from March through October 2021 at eight US healthcare systems. Primary outcomes were admission to an intensive care unit (ICU) and severe illness (score ≥6 on the World Health Organization [WHO] Clinical Progression Scale). We compared the risk of outcomes among those who had completed a COVID-19 vaccine primary series versus those who were unvaccinated. We incorporated inverse propensity weights for vaccination status in a doubly robust regression model to estimate the causal average treatment effect. RESULTS: The causal risk ratio in vaccinated versus unvaccinated was 0.36 (95% confidence interval [CI], 0.15-0.94) for ICU admission and 0.46 (95% CI, 0.25-0.76) for severe illness. CONCLUSION: Among hospitalized patients, reduced disease severity in those vaccinated against COVID-19 supports the absence of VAED.

Racial and ethnic disparities in influenza vaccination coverage among pregnant women in the United States: The contribution of vaccine-related attitudes.

OBJECTIVE: Racial and ethnic disparities in influenza vaccination coverage among pregnant women in the United States have been documented. This study assessed the contribution of vaccine-related attitudes to coverage disparities. METHODS: Surveys were conducted following the 2019-2020 and 2020-2021 influenza seasons in a US research network. Using electronic health record data to identify pregnant women, random samples were selected for surveying; non-Hispanic Black women and influenza-unvaccinated women were oversampled. Regression-based decomposition analyses were used to assess the contribution of vaccine-related attitudes to racial and ethnic differences in influenza vaccination. Data were combined across survey years, and analyses were weighted and accounted for survey design. RESULTS: Survey response rate was 41.2% (721 of 1748) for 2019-2020 and 39.3% (706 of 1798) for 2020-2021. Self-reported influenza vaccination was higher among non-Hispanic White respondents (79.4% coverage, 95% CI 73.1%-85.7%) than Hispanic (66.2% coverage, 95% CI 52.5%-79.9%) and non-Hispanic Black (55.8% coverage, 95% CI 50.2%-61.4%) respondents. For all racial and ethnic groups, a high proportion (generally >80%) reported being seen for care, recommended for influenza vaccination, and offered vaccination. In decomposition analyses, vaccine-related attitudes (e.g., worry about vaccination causing influenza; concern about vaccine safety and effectiveness) explained a statistically significant portion of the observed racial and ethnic disparities in vaccination. Maternal age, education, and health status were not significant contributors after controlling for vaccine-related attitudes. CONCLUSIONS: In a setting with relatively high influenza vaccination coverage among pregnant women, racial and ethnic disparities in coverage were identified. Vaccine-related attitudes were associated with the disparities observed.

Receipt of COVID-19 Vaccine During Pregnancy and Preterm or Small-for-Gestational-Age at Birth - Eight Integrated Health Care Organizations, United States, December 15, 2020-July 22, 2021.

COVID-19 vaccines are recommended during pregnancy to prevent severe maternal morbidity and adverse birth outcomes; however, vaccination coverage among pregnant women has been low (1). Concerns among pregnant women regarding vaccine safety are a persistent barrier to vaccine acceptance during pregnancy. Previous studies of maternal COVID-19 vaccination and birth outcomes have been limited by small sample size (2) or lack of an unvaccinated comparison group (3). In this retrospective cohort study of live births from eight Vaccine Safety Datalink (VSD) health care organizations, risks for preterm birth (<37 weeks' gestation) and small-for-gestational-age (SGA) at birth (birthweight <10th percentile for gestational age) after COVID-19 vaccination (receipt of ≥1 COVID-19 vaccine doses) during pregnancy were evaluated. Risks for preterm and SGA at birth among vaccinated and unvaccinated pregnant women were compared, accounting for time-dependent vaccine exposures and propensity to be vaccinated. Single-gestation pregnancies with estimated start or last menstrual period during May 17-October 24, 2020, were eligible for inclusion. Among 46,079 pregnant women with live births and gestational age available, 10,064 (21.8%) received ≥1 COVID-19 vaccine doses during pregnancy and during December 15, 2020-July 22, 2021; nearly all (9,892; 98.3%) were vaccinated during the second or third trimester. COVID-19 vaccination during pregnancy was not associated with preterm birth (adjusted hazard ratio [aHR] = 0.91; 95% CI = 0.82-1.01). Among 40,627 live births with birthweight available, COVID-19 vaccination in pregnancy was not associated with SGA at birth (aHR = 0.95; 95% CI = 0.87-1.03). Results consistently showed no increased risk when stratified by mRNA COVID-19 vaccine dose, or by second or third trimester vaccination, compared with risk among unvaccinated pregnant women. Because of the small number of first-trimester exposures, aHRs for first-trimester vaccination could not be calculated. These data add to the evidence supporting the safety of COVID-19 vaccination during pregnancy. To reduce the risk for severe COVID-19-associated illness, CDC recommends COVID-19 vaccination for women who are pregnant, recently pregnant (including those who are lactating), who are trying to become pregnant now, or who might become pregnant in the future (4).

Adverse Outcomes in Pregnant Women Hospitalized With Respiratory Syncytial Virus Infection: A Case Series.

We identified 10 women hospitalized with respiratory syncytial virus infection during pregnancy. Diagnoses included pneumonia/atelectasis (5), respiratory failure (2), and sepsis (2). Six had obstetrical complications during hospitalization, including 1 induced preterm birth. One required intensive care unit admission and mechanical ventilation. Four infants had complications at birth.

The use of natural language processing to identify vaccine-related anaphylaxis at five health care systems in the Vaccine Safety Datalink.

PURPOSE: The objective was to develop a natural language processing (NLP) algorithm to identify vaccine-related anaphylaxis from plain-text clinical notes, and to implement the algorithm at five health care systems in the Vaccine Safety Datalink. METHODS: The NLP algorithm was developed using an internal NLP tool and training dataset of 311 potential anaphylaxis cases from Kaiser Permanente Southern California (KPSC). We applied the algorithm to the notes of another 731 potential cases (423 from KPSC; 308 from other sites) with relevant codes (ICD-9-CM diagnosis codes for anaphylaxis, vaccine adverse reactions, and allergic reactions; Healthcare Common Procedure Coding System codes for epinephrine administration). NLP results were compared against a reference standard of chart reviewed and adjudicated cases. The algorithm was then separately applied to the notes of 6 427 359 KPSC vaccination visits (9 402 194 vaccine doses) without relevant codes. RESULTS: At KPSC, NLP identified 12 of 16 true vaccine-related cases and achieved a sensitivity of 75.0%, specificity of 98.5%, positive predictive value (PPV) of 66.7%, and negative predictive value of 99.0% when applied to notes of patients with relevant diagnosis codes. NLP did not identify the five true cases at other sites. When NLP was applied to the notes of KPSC patients without relevant codes, it captured eight additional true cases confirmed by chart review and adjudication. CONCLUSIONS: The current study demonstrated the potential to apply rule-based NLP algorithms to clinical notes to identify anaphylaxis cases. Increasing the size of training data, including clinical notes from all participating study sites in the training data, and preprocessing the clinical notes to handle special characters could improve the performance of the NLP algorithms. We recommend adding an NLP process followed by manual chart review in future vaccine safety studies to improve sensitivity and efficiency.

Vaccine-associated hypersensitivity.

Vaccine-associated hypersensitivity reactions are not infrequent; however, serious acute-onset, presumably IgE-mediated or IgG and complement-mediated anaphylactic or serious delayed-onset T cell-mediated systemic reactions are considered extremely rare. Hypersensitivity can occur because of either the active vaccine component (antigen) or one of the other components. Postvaccination acute-onset hypersensitivity reactions include self-limited localized adverse events and, rarely, systemic reactions ranging from urticaria/angioedema to full-blown anaphylaxis with multisystem involvement. Risk of anaphylaxis after all vaccines is estimated to be 1.31 (95% CI, 0.90-1.84) per million vaccine doses, respectively. Serious hypersensitivity reactions after influenza vaccines are particularly important because of the large number of persons vaccinated annually. Influenza vaccines are unique in requiring annual changes in the vaccines' antigenic composition to match the predicted circulating influenza strains. Recently, novel influenza vaccine types were introduced in the United States (recombinant vaccines, some with higher antigen content and a new adjuvanted vaccine). Providers should be aware of changing recommendations on the basis of recent published evidence for persons with a history of egg allergy to receive annual influenza vaccination. Further research is needed to elucidate the pathophysiology and risk factors for reported vaccine-associated adverse events. Further research is also needed to determine whether repeated annual inactivated influenza vaccination, the number of vaccine antigens administered at the same time, and the current timing of routine infant vaccinations are optimal for overall population well-being.

Meningococcal conjugate vaccine safety surveillance in the Vaccine Safety Datalink using a tree-temporal scan data mining method.

PURPOSE: The objective of our study was to conduct a data mining analysis to identify potential adverse events (AEs) following MENACWY-D using the tree-temporal scan statistic in the Vaccine Safety Datalink population and demonstrate the feasibility of this method in a large distributed safety data setting. METHODS: Traditional pharmacovigilance techniques used in vaccine safety are generally geared to detecting AEs based on pre-defined sets of conditions or diagnoses. Using a newly developed tree-temporal scan statistic data mining method, we performed a pilot study to evaluate the safety profile of the meningococcal conjugate vaccine Menactra® (MenACWY-D), screening thousands of potential AE diagnoses and diagnosis groupings. The study cohort included enrolled participants in the Vaccine Safety Datalink aged 11 to 18 years who had received MenACWY-D vaccination(s) between 2005 and 2014. The tree-temporal scan statistic was employed to identify statistical associations (signals) of AEs following MENACWY-D at a 0.05 level of significance, adjusted for multiple testing. RESULTS: We detected signals for 2 groups of outcomes: diseases of the skin and subcutaneous tissue, fever, and urticaria. Both groups are known AEs following MENACWY-D vaccination. We also identified a statistical signal for pleurisy, but further examination suggested it was likely a false signal. No new MENACWY-D safety concerns were raised. CONCLUSIONS: As a pilot study, we demonstrated that the tree-temporal scan statistic data mining method can be successfully applied to screen broadly for a wide range of vaccine-AE associations within a large health care data network.

Safety of repeated doses of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine in adults and adolescents.

In light of waning immunity to pertussis following receipt of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine, maintaining protection may require repeated Tdap vaccination. We evaluated the safety of repeated doses of tetanus-containing vaccine in 68 915 nonpregnant adolescents and adults in the Vaccine Safety Datalink population who had received an initial dose of Tdap. Compared with 7521 subjects who received a subsequent dose of tetanus toxoid, reduced diphtheria (Td) vaccine, the 61 394 subjects who received a subsequent dose of Tdap did not have significantly elevated risk of medical visits for seizure, cranial nerve disorders, limb swelling, pain in limb, cellulitis, paralytic syndromes, or encephalopathy/encephalitis/meningitis. These results suggest that repeated Tdap vaccination has acceptable safety relative to Tdap vaccination followed by Td vaccination.

Risk of Nontargeted Infectious Disease Hospitalizations Among US Children Following Inactivated and Live Vaccines, 2005-2014.

Background: Recent studies have shown that some vaccines have beneficial effects that cannot be explained solely by the prevention of their respective targeted disease(s). Methods: We used the MarketScan US Commercial Claims Databases for 2005 to 2014 to assess the risk of hospital admission for nontargeted infectious (NTI) diseases in children aged 16 through 24 months according to the last vaccine type (live and/or inactivated). We included children continuously enrolled within a month of birth through 15 months who received at least 3 doses of diphtheria-tetanus-acellular pertussis vaccine by the end of 15 months of age. We used Cox regression to estimate hazard ratios (HRs), stratifying by birthdate to control for age, year, and seasonality and adjusting for sex, chronic diseases, prior hospitalizations, number of outpatient visits, region of residence, urban/rural area of domicile, prematurity, low birth weight, and mother's age. Results: 311663 children were included. In adjusted analyses, risk of hospitalization for NTI from ages 16 through 24 months was reduced for those who received live vaccine alone compared with inactivated alone or concurrent live and inactivated vaccines (HR, 0.50; 95% confidence interval [CI], 0.43, 0.57 and HR, 0.78; 95% CI, 0.67, 0.91, respectively) and for those who received live and inactivated vaccines concurrently compared with inactivated-only (HR, 0.64; 95% CI, 0.58, 0.70). Conclusions: We found lower risk of NTI disease hospitalizations from age 16 through 24 months among children whose last vaccine received was live compared with inactivated vaccine, as well as concurrent receipt compared with inactivated vaccine.

Association between parent attitudes and receipt of human papillomavirus vaccine in adolescents.

BACKGROUND: Human papillomavirus (HPV) vaccine coverage rates remain low. This is believed to reflect parental hesitancy, but few studies have examined how changes in parents' attitudes impact HPV vaccine uptake. This study examined the association between changes in parents' vaccine attitudes and HPV vaccine receipt in their adolescent children. METHODS: A baseline and 1-year follow-up survey of HPV vaccine attitudes was administered to parents of 11-17 year olds who had not completed the HPV vaccine series. Changes in attitudinal scores (barriers, harms, ineffectiveness, and uncertainties) from the Carolina HPV Immunization Attitudes and Beliefs Scale were assessed. Two outcomes were measured (in parents' adolescent children) over an 18-month period and analyzed using multivariable regression; receipt of next scheduled HPV vaccine dose and 3-dose series completion. RESULTS: There were 221 parents who completed the baseline survey (11% response rate) and 164 with available follow-up data; 60% of their adolescent children received a next HPV vaccine dose and 38% completed the vaccine series at follow-up. Decrease in parents' uncertainties was a significant predictor of vaccine receipt, with each 1-point reduction in uncertainties score associated with 4.9 higher odds of receipt of the next vaccine dose. Higher baseline harms score was the only significant predictor of lower series completion. CONCLUSIONS: Reductions in parents' uncertainties appeared to result in greater likelihood of their children receiving the HPV vaccine. Only baseline concerns about vaccine harms were associated with lower series completion rate. Education for parents should emphasize the HPV vaccine's safety profile.

Risk of anaphylaxis after vaccination in children and adults.

BACKGROUND: Anaphylaxis is a potentially life-threatening allergic reaction. The risk of anaphylaxis after vaccination has not been well described in adults or with newer vaccines in children. OBJECTIVE: We sought to estimate the incidence of anaphylaxis after vaccines and describe the demographic and clinical characteristics of confirmed cases of anaphylaxis. METHODS: Using health care data from the Vaccine Safety Datalink, we determined rates of anaphylaxis after vaccination in children and adults. We first identified all patients with a vaccination record from January 2009 through December 2011 and used diagnostic and procedure codes to identify potential anaphylaxis cases. Medical records of potential cases were reviewed. Confirmed cases met the Brighton Collaboration definition for anaphylaxis and had to be determined to be vaccine triggered. We calculated the incidence of anaphylaxis after all vaccines combined and for selected individual vaccines. RESULTS: We identified 33 confirmed vaccine-triggered anaphylaxis cases that occurred after 25,173,965 vaccine doses. The rate of anaphylaxis was 1.31 (95% CI, 0.90-1.84) per million vaccine doses. The incidence did not vary significantly by age, and there was a nonsignificant female predominance. Vaccine-specific rates included 1.35 (95% CI, 0.65-2.47) per million doses for inactivated trivalent influenza vaccine (10 cases, 7,434,628 doses given alone) and 1.83 (95% CI, 0.22-6.63) per million doses for inactivated monovalent influenza vaccine (2 cases, 1,090,279 doses given alone). The onset of symptoms among cases was within 30 minutes (8 cases), 30 to less than 120 minutes (8 cases), 2 to less than 4 hours (10 cases), 4 to 8 hours (2 cases), the next day (1 case), and not documented (4 cases). CONCLUSION: Anaphylaxis after vaccination is rare in all age groups. Despite its rarity, anaphylaxis is a potentially life-threatening medical emergency that vaccine providers need to be prepared to treat.

Post licensure surveillance of influenza vaccines in the Vaccine Safety Datalink in the 2013-2014 and 2014-2015 seasons.

PURPOSE: The changes in each year in influenza vaccine antigenic components as well as vaccine administration patterns may pose new risks of adverse events following immunization (AEs). To evaluate the safety of influenza vaccines annually administered to people ≥ 6 months, we conducted weekly post licensure surveillance for seven pre-specified adverse events following receipt of influenza vaccines during the 2013-2014 and 2014-2015 seasons in the Vaccine Safety Datalink (VSD). METHODS: We used both a historically-controlled cohort design with the Poisson-based maximized sequential probability ratio test (maxSPRT) and a self-controlled risk interval (SCRI) design with the binomial-based maxSPRT. For each adverse event outcome, we defined the risk interval on the basis of biologic plausibility and prior literature. For the historical cohort design, numbers of expected adverse events were calculated from the prior seven seasons, adjusted for age and site. For the SCRI design, a comparison window was defined either before vaccination or after vaccination, depending on each specific outcome. RESULTS: An elevated risk of febrile seizures 0-1 days following trivalent inactivated influenza vaccine (IIV3) was identified in children aged 6-23 months during the 2014-2015 season using the SCRI design. We found the relative risk (RR) of febrile seizures following concomitant administration of IIV3 and PCV13 was 5.3 with a 95% CI 1.87-14.75. Without concomitant PCV 13 administration, the estimated risk decreased and was no longer statistically significant (RR: 1.4; CI: 0.54 - 3.61). CONCLUSION: No increased risks, other than for febrile seizures, were identified in influenza vaccine safety surveillance during 2013-2014 and 2014-2015 seasons in the VSD. Copyright © 2016 John Wiley & Sons, Ltd.

Adverse Events Following Measles, Mumps, and Rubella Vaccine in Adults Reported to the Vaccine Adverse Event Reporting System (VAERS), 2003-2013.

BACKGROUND: Limited data exist on the safety of the measles, mumps, and rubella (MMR) vaccine in adults. We reviewed reports of adverse events (AEs) to the Vaccine Adverse Event Reporting System (VAERS) to assess safety in this previously understudied group. METHODS: VAERS is the national spontaneous vaccine safety surveillance system coadministered by the Centers for Disease Control and Prevention and the US Food and Drug Administration. We searched the VAERS database for US reports of adults aged ≥19 years who received the MMR vaccine from 1 January 2003 to 31 July 2013. We clinically reviewed reports and available medical records for serious AEs, pregnancy reports, and reports for selected prespecified outcomes. RESULTS: During this period, VAERS received 3175 US reports after MMR vaccine in adults. Of these, 168 (5%) were classified as serious, including 7 reports of death. Females accounted for 77% of reports. The most common signs and symptoms for all reports were pyrexia (19%), rash (17%), pain (13%), and arthralgia (13%). We did not detect any new safety findings in empirical Bayesian data mining. We identified 131 reports of MMR vaccine administered to a pregnant woman; the majority of these vaccinations were in the first trimester and in 83 (62%), no AE was reported. CONCLUSIONS: In our review of VAERS data, we did not detect any new or unexpected safety concerns for MMR vaccination in adults. We identified reports of pregnant women exposed to MMR, which is a group in whom the vaccine is contraindicated, suggesting the need for continued provider education on vaccine recommendations and screening.

Association of Tdap Vaccination With Acute Events and Adverse Birth Outcomes Among Pregnant Women With Prior Tetanus-Containing Immunizations.

IMPORTANCE: The Advisory Committee on Immunization Practices (ACIP) recommends the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine for pregnant women during each pregnancy, regardless of prior immunization status. However, safety data on repeated Tdap vaccination in pregnancy is lacking. OBJECTIVE: To determine whether receipt of Tdap vaccine during pregnancy administered in close intervals from prior tetanus-containing vaccinations is associated with acute adverse events in mothers and adverse birth outcomes in neonates. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study in 29,155 pregnant women aged 14 through 49 years from January 1, 2007, through November 15, 2013, using data from 7 Vaccine Safety Datalink sites in California, Colorado, Minnesota, Oregon, Washington, and Wisconsin. EXPOSURES: Women who received Tdap in pregnancy following a prior tetanus-containing vaccine less than 2 years before, 2 to 5 years before, and more than 5 years before. MAIN OUTCOMES AND MEASURES: Acute adverse events (fever, allergy, and local reactions) and adverse birth outcomes (small for gestational age, preterm delivery, and low birth weight) were evaluated. Women who were vaccinated with Tdap in pregnancy and had a prior tetanus-containing vaccine more than 5 years before served as controls. RESULTS: There were no statistically significant differences in rates of medically attended acute adverse events or adverse birth outcomes related to timing since prior tetanus-containing vaccination. [table: see text]. CONCLUSIONS AND RELEVANCE: Among women who received Tdap vaccination during pregnancy, there was no increased risk of acute adverse events or adverse birth outcomes for those who had been previously vaccinated less than 2 years before or 2 to 5 years before compared with those who had been vaccinated more than 5 years before. These findings suggest that relatively recent receipt of a prior tetanus-containing vaccination does not increase risk after Tdap vaccination in pregnancy.

Continuous sequential boundaries for vaccine safety surveillance.

Various recently developed sequential methods have been used to detect signals for post-marketing surveillance in drug and vaccine safety. Among these, the maximized sequential probability ratio test (MaxSPRT) has been used to detect elevated risks of adverse events following vaccination using large healthcare databases. However, a limitation of MaxSPRT is that it only provides a time-invariant flat boundary. In this study, we propose the use of time-varying boundaries for controlling how type I error is distributed throughout the surveillance period. This is especially useful in two scenarios: (i) when we desire generally larger sample sizes before a signal is generated, for example, when early adopters are not representative of the larger population; and (ii) when it is desired for a signal to be generated as early as possible, for example, when the adverse event is considered rare but serious. We consider four specific time-varying boundaries (which we call critical value functions), and we study their statistical power and average time to signal detection. The methodology we present here can be viewed as a generalization or flexible extension of MaxSPRT.

A Texting- and Internet-Based Self-Reporting System for Enhanced Vaccine Safety Surveillance With Insights From a Large Integrated Health Care System in the United States: Prospective Cohort Study.

BACKGROUND: SMS text messaging- and internet-based self-reporting systems can supplement existing vaccine safety surveillance systems, but real-world participation patterns have not been assessed at scale. OBJECTIVE: This study aimed to describe the participation rates of a new SMS text messaging- and internet-based self-reporting system called the Kaiser Permanente Side Effect Monitor (KPSEM) within a large integrated health care system. METHODS: We conducted a prospective cohort study of Kaiser Permanente Southern California (KPSC) patients receiving a COVID-19 vaccination from April 23, 2021, to July 31, 2023. Patients received invitations through flyers, SMS text messages, emails, or patient health care portals. After consenting, patients received regular surveys to assess adverse events up to 5 weeks after each dose. Linkage with medical records provided demographic and clinical data. In this study, we describe KPSEM participation rates, defined as providing consent and completing at least 1 survey within 35 days of COVID-19 vaccination. RESULTS: Approximately, 8% (164,636/2,091,975) of all vaccinated patients provided consent and completed at least 1 survey within 35 days. The lowest participation rates were observed for parents of children aged 12-17 years (1349/152,928, 0.9% participation rate), and the highest participation was observed among older adults aged 61-70 years (39,844/329,487, 12.1%). Persons of non-Hispanic White race were more likely to participate compared with other races and ethnicities (13.1% vs 3.9%-7.5%, respectively; P<.001). In addition, patients residing in areas with a higher neighborhood deprivation index were less likely to participate (5.1%, 16,503/323,122 vs 10.8%, 38,084/352,939 in the highest vs lowest deprivation quintiles, respectively; P<.001). Invitations through the individual's Kaiser Permanente health care portal account and by SMS text message were associated with the highest participation rate (19.2%, 70,248/366,377 and 10.5%, 96,169/914,793, respectively), followed by email (19,464/396,912, 4.9%) and then QR codes on flyers (25,882/2,091,975, 1.2%). SMS text messaging-based surveys demonstrated the highest sustained daily response rates compared with internet-based surveys. CONCLUSIONS: This real-world prospective study demonstrated that a novel digital vaccine safety self-reporting system implemented through an integrated health care system can achieve high participation rates. Linkage with participants' electronic health records is another unique benefit of this surveillance system. We also identified lower participation among selected vulnerable populations, which may have implications when interpreting data collected from similar digital systems.

Disparities in COVID-19 vaccination receipt by race, ethnicity, and social determinants of health among a large patient population in a network of community-based healthcare centers.

BACKGROUND: There are known disparities in U.S. COVID-19 vaccination but there is limited information on national vaccine uptake in a large, racially diverse, all-age population. Here, we describe COVID-19 vaccination coverage in a large U.S. population accessing care in OCHIN (not an acronym), a national network of community-based healthcare organizations. METHODS: Within OCHIN, we identified patients aged 6 months and older with ≥1 completed clinical encounter since becoming age-eligible for the COVID-19 vaccine between December 13, 2020 and December 31, 2022. Patients' COVID-19 vaccination status was assessed from OCHIN's Epic® electronic health record which includes data from state immunization information systems. Patients were considered vaccinated if they received ≥1 dose of a monovalent vaccine product; coverage was categorized by age groups (6 months-4 years; 5-11 years, 12-15 years, 16+ years). Multivariate analyses assessed factors associated with COVID-19 vaccination across age groups. RESULTS: The cohort included 3.3 million Hispanic (37 %), non-Hispanic (NH) White (31 %), NH Black (15 %), and NH Asian (7 %) patients; 45 % of whom were Medicaid-enrolled, 19 % uninsured, and 53 % with a household income below 100 % of the federal poverty level. The proportion with ≥1 COVID-19 vaccine dose increased with age, from 11.7 % (6 months through 4 years) to 72.3 % (65 years and older). The only factors associated with significantly higher COVID-19 vaccine coverage across age groups were prior receipt of an influenza vaccine and having private insurance. In adjusted modeling, when compared to NH whites, COVID-19 vaccine coverage was significantly higher among Hispanic, NH Asian, and NH multiple-race patients aged ≥5 years and significantly lower among NH Black and NH Native Hawaiian/Other Pacific Islander patients aged 6 months-4 years old. CONCLUSIONS: We identified disparities in primary series COVID-19 vaccine coverage by age, race and ethnicity, household income, insurance status, and prior influenza vaccination within this large, diverse population accessing care in community-based healthcare organizations.

Safety of Simultaneous Vaccination With Adjuvanted Zoster Vaccine and Adjuvanted Influenza Vaccine: A Randomized Clinical Trial.

Importance: Quadrivalent adjuvanted inactivated influenza vaccine (aIIV4) and adjuvanted recombinant zoster vaccine (RZV) contain novel adjuvants. Data are limited on the comparative safety, reactogenicity, and health-related quality of life (HRQOL) effects of the simultaneous administration of these vaccines. Objective: To compare the safety and reactogenicity after simultaneous doses of RZV and aIIV4 administration (opposite arms) with simultaneous doses of RZV with quadrivalent high-dose inactivated influenza vaccine [HD-IIV4]). Design, Setting, and Participants: This randomized blinded clinical trial was conducted during the 2021-2022 and 2022-2023 influenza seasons at 2 centers in the US among community-dwelling adults aged 65 years or older. Analysis was performed on an intention-to-treat basis. Intervention: Simultaneous intramuscular administration of RZV dose 1 and aIIV4 or HD-IIV4 in opposite arms after age stratification (65-69 and ≥70 years) and randomization. Main Outcomes and Measures: The primary outcome was the proportions of participants with 1 or more severe solicited reactions during days 1 to 8, using a noninferiority test (10% noninferiority margin). Additional measures included serious adverse events and adverse events of clinical interest during days 1 to 43 of the study period. Results: A total of 267 adults (median age, 71 years [range, 65-92 years]; 137 men [51.3%]) were randomized; 130 received simultaneous RZV and aIIV4, and 137 received simultaneous RZV and HD-IIV4. The proportion of patients reporting 1 or more severe reactions after simultaneous administration of RZV and aIIV4 (15 of 115 [11.5%]) was noninferior compared with simultaneous RZV and HD-IIV4 (17 of 119 [12.5%]) (absolute difference, -1.0% [95% CI, -8.9% to 7.1%]). There were no significant differences in the number of serious adverse events or adverse events of clinical interest between the groups. Conclusions and Relevance: In this clinical trial of simultaneous doses of RZV and aIIV4 compared with simultaneous doses of RZV and HD-IIV4, overall safety findings were similar between groups. From a safety standpoint, this study supports the simultaneous administration of RZV and aIIV4 among older adults. Trial Registration: ClinicalTrials.gov Identifier: NCT05007041.

Influenza vaccination accuracy among adults: Self-report compared with electronic health record data.

OBJECTIVE: To assess the validity of electronic health record (EHR)-based influenza vaccination data among adults in a multistate network. METHODS: Following the 2018-2019 and 2019-2020 influenza seasons, surveys were conducted among a random sample of adults who did or did not appear influenza-vaccinated (per EHR data) during the influenza season. Participants were asked to report their influenza vaccination status; self-report was treated as the criterion standard. Results were combined across survey years. RESULTS: Survey response rate was 44.7% (777 of 1740) for the 2018-2019 influenza season and 40.5% (505 of 1246) for the 2019-2020 influenza season. The sensitivity of EHR-based influenza vaccination data was 75.0% (95% confidence interval [CI] 68.1, 81.1), specificity 98.4% (95% CI 92.9, 99.9), and negative predictive value 73.9% (95% CI 68.0, 79.3). CONCLUSIONS: In a multistate research network across two recent influenza seasons, there was moderate concordance between EHR-based vaccination data and self-report.