Did Risk-based or Age-based Vaccine Prioritization for Covid-19 Save More Lives?

ImportanceAll U.S. states provided Covid-19 vaccine access to frontline healthcare workers first, but after that, states varied in whether they gave earlier access to the elderly, versus the vulnerable with comorbidities, or school employees or essential workers, reflecting the underlying scientific and policy uncertainty. ObjectiveTo evaluate if risk-based or age-based prioritization is more effective at reducing reported Covid-19 cases and deaths. DesignA serial cross-sectional study Setting50 U.S. states and Washington D.C. Participants60+ years of age, high-risk individuals, K-12 school employees, and essential workers Main Outcomes and MeasuresHospitalizations and deaths ResultsSeven to nine weeks after 60-year-olds became eligible for a vaccine, there was a statistically significant 40-50% decline in Covid-19 hospitalizations in that state. In contrast, there was no statistically detectable change in hospitalizations in the 7-9 weeks after K-12 employees become eligible for vaccines. Vaccine eligibility of "high-risk adults" and "essential workers" produces effects somewhere in the middle, with reductions in hospitalization of about 25%. There was a large statistically significant decline in death rates (25-38%) 10 to 11 weeks after people aged over 60 became vaccine-eligible. These effects were generally statistically larger than high risk individuals, K-12 school employees, and essential workers. Conclusions and RelevancePanel data analysis of weekly variation in Covid-19 health outcomes reveals that prioritizing adults 60+ years of age is associated with the largest reduction in hospitalizations and Covid-19 cases, followed by vaccines for adults with high-risk comorbidities. Vaccinations extended to K-12 school employees and essential workers is associated with the smallest reductions in hospitalizations and deaths. Key PointsO_ST_ABSQuestionC_ST_ABSDid Risk-based or Age-based Vaccine Prioritization for Covid-19 Save More Lives? FindingsPanel data analysis of weekly variation in Covid-19 health outcomes reveals that prioritizing adults 60+ years of age is associated with the largest reduction in hospitalizations and Covid-19 cases, followed by vaccines for adults with high-risk comorbidities. Vaccinations extended to K-12 school employees and essential workers is associated with the smallest reductions in hospitalizations and deaths. MeaningPrioritizing adults 60+ years of age can lead to a higher estimated reduction in hospitalizations and deaths, followed by a strategy of prioritizing adults with high-risk comorbidities. Our findings add to the limited evidence for the roadmap for prioritizing use of Covid-19 vaccines, and help address uncertainties about the relative effectiveness of different vaccine strategies.