Effectiveness of Community-Engaged Research Strategies in Increasing COVID-19 Vaccinations in Targeted Communities: The Community Engagement Alliance (CEAL) Regional Teams

Objectives. To explore a key outcome of interest for the Community Engagement Alliance (CEAL) Regional Teams by examining COVID-19 vaccinations over time in US counties where CEAL teams operated and comparing them to demographically similar counties in the same state. Methods. Our evaluation used a nonequivalent control group design. Each county where a CEAL team operated was matched to a unique non-CEAL county in the same state. Components of the Centers for Disease Control and Prevention's Social Vulnerability Index were used as the matching criteria. COVID-19 vaccinations (county-level percentage of residents aged 18 years or older who are fully vaccinated) for CEAL and matched counties were analyzed over time. Results. The mean percentage of vaccinated adults was significantly higher in CEAL counties than in matched non-CEAL counties. Sensitivity analyses confirmed conclusions did not change depending on the CEAL cohort or closeness of matches. Conclusions. Our findings support CEAL team efforts to increase COVID-19 vaccinations in target communities and employ community-engaged research more broadly within public health contexts. (Am J Public Health. 2024;114(S1):S124-S127. https://doi.org/10.2105/AJPH.2023.307517).

Population-Weighted Seroprevalence From Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection, Vaccination, and Hybrid Immunity Among US Blood Donations From January to December 2021

BACKGROUND

Previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) vaccination, independently and combined ("hybrid immunity"), result in partial protection from subsequent infection and strong protection from severe disease. Proportions of the US population who have been infected, vaccinated, or have hybrid immunity remain unclear, posing a challenge for assessing effective pandemic mitigation strategies.

METHODS

In this serial cross-sectional study, nationwide blood donor specimens collected during January-December 2021 were tested for anti-spike and anti-nucleocapsid antibodies, and donor COVID-19 vaccination history of ≥1 dose was collected. Monthly seroprevalence induced from SARS-CoV-2 infection, COVID-19 vaccination, or both, were estimated. Estimates were weighted to account for demographic differences from the general population and were compared temporally and by demographic factors.

RESULTS

Overall, 1 123 855 blood samples were assayed. From January to December 2021, the weighted percentage of donations with seropositivity changed as follows: seropositivity due to vaccination without previous infection, increase from 3.5% (95% confidence interval, 3.4%-3.7%) to 64.0%, (63.5%-64.5%); seropositivity due to previous infection without vaccination, decrease from 15.6% (15.2%-16.0%) to 11.7% (11.4%-12.0%); and seropositivity due to hybrid immunity, increase from 0.7% (0.6%-0.7%) to 18.9% (18.5%-19.3%). Combined seroprevalence from infection, vaccination, or both increased from 19.8% (19.3%-20.2%) to 94.5% (93.5%-94.0%). Infection- and vaccination-induced antibody responses varied significantly by age, race-ethnicity, and region, but not by sex.

CONCLUSIONS

Our results indicate substantial increases in population humoral immunity from SARS-CoV-2 infection, COVID-19 vaccination, and hybrid immunity during 2021. These findings are important to consider in future COVID-19 studies and long-term pandemic mitigation efforts.