SARS-CoV-2 vaccines are powerful tools to combat the COVID-19 pandemic, but vaccine hesitancy threatens these vaccines' effectiveness. To address COVID-19 vaccine hesitancy and ensure equitable distribution, understanding the extent of and factors associated with vaccine hesitancy is critical. We report the results of a large nationwide study conducted December 2020-January 2021 of 34,470 users from COVID-19-focused smartphone-based app How We Feel on their willingness to receive a COVID-19 vaccine. Nineteen percent of respondents expressed vaccine hesitancy, the majority being undecided. Vaccine hesitancy was significant among females, younger people, minority and low-income communities, healthcare and essential workers, rural residents, geographical regions with higher COVID-19 burden, those who did not use protective measures, and those who did not receive COVID-19 tests. Our findings support the need for targeted efforts to develop education and outreach programs to overcome vaccine hesitancy and improve equitable access, diversity, and inclusion in the national response to COVID-19.

Background Little was known about US parental attitudes, beliefs, and intentions surrounding coronavirus disease 2019 (COVID-19) vaccines for children before their introduction. Methods An online cross-sectional nationally representative survey of US parents/guardians of children < 18 years old via Ipsos KnowledgePanel, fielded from October 26, 2021 to November 30, 2021. Results Response rate was 64.2% (3230/5034). For children ages 0–4 years, 51.5% of parents were likely to have their children vaccinated, and for ages 5–11 and 12–17, 54.0% and 69.7% of parents, respectively, reported they were likely to vaccinate or had already vaccinated their children. Among respondents with unvaccinated children, 25.2% (ages 0–4) and 22.0% (ages 5–11) reported they would seek COVID-19 vaccination for their children as soon as authorization occurred. Factors associated with willingness to have children receive a COVID-19 vaccine were: belief in benefits of COVID-19 vaccination (odds ratio [OR] = 6.44, 5.68, 4.57 in ages 0–4, 5–11, and 12–17 respectively), acceptance of routine childhood vaccines (OR = 6.42, 5.48, 1.76), parental COVID-19 vaccination (OR = 1.85, 3.70, 6.16), perceptions that pediatric COVID-19 is severe (OR = 1.89, 1.72, 1.35), Hispanic ethnicity (OR = 2.07, 2.29, 2.60), influenza vaccine acceptance (OR = 1.07, 0.88, 1.62), presence of children of another age group in the household (OR = 0.71, 0.71, 0.65), and attitudinal barriers to COVID-19 vaccination (OR = 0.30, 0.26, 0.49). Conclusions Belief in the benefits of COVID-19 vaccination and acceptance of routine childhood vaccines are the strongest predictors of intention to vaccinate children. Further research is needed to track how parental attitudes change as more data about pediatric COVID-19 vaccines become available and how intentions translate into pediatric vaccine uptake.

COVID-19 vaccine trials provide valuable insight into the safety and efficacy of vaccines, with individually-randomized, placebo-controlled trials being the gold standard in trial design. However, a myriad of variables must be considered as clinical trial data are interpreted and used to guide policy decisions. These variables include factors such as the characteristics of the study population and circulating SARS-CoV-2 strains, the force of infection, the definition and ascertainment of endpoints, the timing of vaccine efficacy assessment, and the potential for performance bias. In this Viewpoint, we discuss critical variables to consider when comparing efficacy measurements across current and future COVID-19 vaccine trials.