Vaccination and non-pharmaceutical interventions during COVID-19: Impact on health and non-health outcomes in the US

Objective

Little is known about the relative effectiveness of COVID-19 vaccination and its interaction with non-pharmaceutical interventions (NPIs) in reducing infections, deaths, COVID-19 reproduction rate, and job losses. This study examined the relative effectiveness of vaccination and NPIs on COVID-19 infection, deaths, reproduction rate, and unemployment rate in the US.

Methods

Retrospective US data at the national level were obtained from the Oxford COVID-19 Government Response Tracker (OxCGRT dataset). Unemployment rate data were obtained from the US Bureau of Labor Statistics. Time-trend analyses of the policy variables and epidemiological outcomes were performed. A regression discontinuity in time was used to investigate the effects of policy variables on health outcomes and unemployment rate.

Results

Based on time-trend analyses, the number of people vaccinated increased starting in March 2021, while the stringency index had steadily declined since early January 2021. A decrease in new COVID-19 cases and deaths was observed during this period. However, despite higher vaccination coverage, new COVID-19 cases and deaths peaked in late 2021 and early 2022. We found that the interaction between treatment effects (vaccinations) and stringency measures was negatively associated with total COVID-19 cases and deaths, implying that some restrictions might be required to reduce rising infections during vaccination campaigns. We also found a negative association between vaccinations and the unemployment rate.

Conclusion

The study findings suggested that vaccinations alone were insufficient to reduce virus spread and deaths, and that some NPIs might be required during the vaccination campaigns.