Lessons learned from COVID-19, H1N1, and routine vaccine pharmacovigilance in the United States: a path to a more robust vaccine safety program.

INTRODUCTION: Vaccine pharmacovigilance is an essential component of vaccine safety programs. Vaccine pharmacovigilance refers to detecting uncommon adverse events following immunization (AEFI), determining whether they are due to the vaccine or are only a coincidence, and, for those AEFI considered related to vaccination, characterizing them further. When AEFI are due to vaccination, it is important to characterize the attributable risk and ascertain the biological mechanism causing the adverse reaction to inform efforts to prevent or mitigate the risk. A robust post-authorization safety system is necessary for vaccine decision-making, clinical recommendations, vaccine compensation, and vaccine communication and confidence. AREAS COVERED: This paper describes the key characteristics of vaccine pharmacovigilance programs, reviews US vaccine pharmacovigilance for routine vaccination programs, COVID-19, and H1N1, and makes recommendations for improving future vaccine safety systems. EXPERT OPINION: The key characteristics of vaccine pharmacovigilance programs include passive surveillance, active surveillance, clinical investigation and special studies, and causality assessment. Recent examples illustrate the strengths of US pharmacovigilance systems, including systems for passive and active surveillance, as well as areas for improvement, including study of pathogenesis, consistent funding, and leadership. We make recommendations that would, if implemented, further strengthen the vaccine safety system for future routine and pandemic immunizations.

Benefit-Risk Assessment of mRNA COVID-19 Vaccines in Children Aged 6 Months to 4 Years in the Omicron Era.

BACKGROUND: There is no risk and benefit assessment of COVID-19 vaccination for children younger than 5 years using a single health outcomes scale. The objective of this study is to compare the expected risk and benefits of the mRNA primary series of COVID-19 vaccines for children aged 6 months to 4 years in the United States using a single health outcome scale in the Omicron era. METHODS: The expected benefits and risks of the primary two-dose series of mRNA COVID-19 vaccines for children aged 6 months to 4 years were stratified by sex, the presence of underlying medical conditions, the presence of infection-induced immunity, and the type of mRNA vaccine (BNT162b2 or mRNA-1273). A scoping literature review was conducted to identify the indicators in the decision tree model. The benefit-risk ratio was the outcome of interest. RESULTS: The benefit-risk ratios ranged from 200.4 in BNT162b2 for males aged 6-11 months with underlying medical conditions and without infection-induced immunity to 3.2 in mRNA-1273 for females aged 1-4 years without underlying medical conditions and with infection-induced immunity. CONCLUSIONS: The expected benefit of receiving the primary series of mRNA vaccines outweighed the risk among children ages 6 months to 4 years regardless of sex, presence of underlying medical conditions, presence of infection-induced immunity, or type of mRNA vaccines. However, the continuous monitoring of the COVID-19 epidemiology as well as vaccine effectiveness and safety is important.

Changes in vaccine attitudes and recommendations among US Healthcare Personnel during the COVID-19 pandemic.

A recommendation from healthcare personnel (HCP) is a strong predictor of vaccination. This study aimed to measure how HCP vaccine attitudes and recommendations changed during the COVID-19 pandemic. HCP were surveyed in January 2023 using a double opt-in network panel. Survey responses were summarized and stratified by HCP type and COVID-19 booster status. Multivariable logistic regression models were fitted. Comparisons were made to a September 2021 survey, with differences tested for significance (p < 0.05) using Pearson's χ2 Test. Nearly 82% of the 1207 HCP surveyed had received a COVID-19 booster, most commonly pediatricians (94%), followed by family medicine doctors (87%), pharmacists (74%), and nurses (73%) (p < 0.01). HCP with high trust in the Centers for Disease Control and Prevention (CDC) had nearly 6 times the odds (OR: 5.5; 95%CI: 3.9-7.7) of being boosted compared to HCP with low trust. From September 2021 to January 2023, the proportion of HCP recommending vaccines (COVID-19 and routine) to their patients decreased substantially for nearly all vaccines and patient populations specified. Trust in CDC also decreased (from 79 to 73%, p < 0.01), as did support for HCP COVID-19 vaccine mandates (from 65 to 46%, p < 0.01). HCP interest in additional online resources to improve their vaccine discussions with patients increased from 46 to 66% (p < 0.01). Additional regularly updated online resources from trusted medical sources that clarify progressing science and address dynamic public concerns are needed to improve vaccine confidence among HCP and help them support their patients' decision-making.

Knowledge, attitudes, and intentions regarding COVID-19 vaccination in the general population and the effect of different framing messages for a brief video on intentions to get vaccinated among unvaccinated individuals in the United States during July 2021.

OBJECTIVE: To identify knowledge, attitudes, and beliefs (KABs) associated with COVID-19 vaccination intentions and assess the impact of vaccine-promoting messages on vaccination intentions. METHODS: Our nationally representative survey measured KABs of COVID-19 vaccination and incorporated a randomized experiment to assess the impact of different framing messages for a video encouraging vaccination intentions among unvaccinated adults in the US. Multivariable multinomial logistic regression models were fitted to investigate the relationships of KABs, trust in public health authorities (PHAs), and vaccine confidence with vaccination intentions. Difference-in-difference estimation was conducted to assess the impact of framing messages for a video on unvaccinated individuals' vaccination intentions. RESULTS: We observed that people with increasingly favorable vaccine KABs, trust in PHAs, and vaccine confidence were more likely to be vaccinated or intend to get vaccinated against COVID-19. Difference-in-difference estimates indicated a positive impact of exposure to the video on vaccination intentions while framing messages in some cases appeared to lower vaccination intentions. Associations between the video and vaccination intentions were more pronounced among Black/African American and Hispanic/Latinx populations and Democrats; however, associations did not vary by trust in PHAs or vaccine confidence. CONCLUSION: Videos that encourage people to get vaccinated may provide an efficient approach to nudge vaccine-hesitant individuals towards getting vaccinated. However, framing messages may negatively impact vaccination intentions and need to be developed carefully. PRACTICE IMPLICATIONS: This study provides solid experimental evidence for the importance of tailoring message framing to the characteristics and experience of the audience, while cautioning potential negative impacts of framing that does not match its intended audience. Our findings are applicable to health communication strategies on the population level, such as mass media campaigns, and the use of framing for messages to encourage vaccination but may also be informative for healthcare professionals consulting hesitant individuals about COVID-19 vaccinations.

Attitudes toward COVID-19 and Other Vaccines: Comparing Parents to Other Adults, September 2022.

Few analyses of COVID-19 vaccine attitudes also cover routine vaccines or focus on parents. In this cross-sectional study, we surveyed US adults in September 2022, immediately following the authorization of updated bivalent COVID-19 boosters for adults but before their authorization for children. The vaccine attitudes of parents were compared to other adults. Fewer parents were up-to-date on COVID-19 vaccines than other adults (54% vs. 67%), even after adjusting for age, education, and race/ethnicity (Adjusted Odds Ratio: 0.58; 95% Confidence Interval: 0.45-0.76). More parents had concerns about COVID-19 vaccines' safety in children (67% vs. 58%; aOR: 1.59; 95%CI: 1.23-2.06) and vaccine ingredients (52% vs. 45%; aOR: 1.41; 95%CI: 1.09-1.81), and more parents perceived COVID-19 in children to be no worse than a cold or the flu (51% vs. 38%; aOR: 1.56; 95%CI: 1.22-2.01). Fewer parents supported COVID-19 vaccine school requirements (52% vs. 57%; aOR: 0.75; 95%CI: 0.58-0.97) and perceived high vaccine coverage among their friends (51% vs. 61%; aOR: 0.60; 95%CI: 0.46-0.78). However, three-quarters of parents intended their child to receive all routinely recommended vaccines, whereas only half of adults intended to receive all routinely recommended vaccines themselves. To improve parental informed vaccine decision-making, public health must ensure pediatric providers have updated resources to support their discussions of vaccine risks and benefits with their patients' parents.