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Publications

Journal Article Preprint Epublish

PubMed: 39802800 DOI: 10.1101/2024.12.30.24319700

Magnitude of Potential Biases in COVID-19 Vaccine Effectiveness Studies due to Differential Healthcare seeking following Home Testing: Implications for Test Negative Design Studies.

medRxiv

Authors: Saba A Qasmieh, Jill M Ferdinands, Jessie R Chung, Ryan E Wiegand, Brendan Flannery, Madhura S Rane, Denis Nash

Affiliations

  • Institute for Implementation Science in Population Health (ISPH), City University of New York (CUNY), New York, NY 10027, USA. Department of Epidemiology and Biostatistics, Graduate School of Public Health and Health Policy, City University of New York (CUNY), New York, NY 10027, USA.
  • Influenza Division, U.S Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
  • Coronavirus and Other Respiratory Viruses Division, U.S Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
  • Institute for Implementation Science in Population Health (ISPH), City University of New York (CUNY), New York, NY 10027, USA.
  • Department of Epidemiology and Biostatistics, Graduate School of Public Health and Health Policy, City University of New York (CUNY), New York, NY 10027, USA.

Abstract

The test-negative design (TND) is widely used to estimate COVID-19 vaccine effectiveness (VE). Biased estimates of VE may result from effects of at-home SARS-CoV-2 rapid diagnostic test (RDT) results on decisions to seek healthcare. To investigate magnitude of potential bias, we constructed decision trees with input probabilities obtained from longitudinal surveys of U.S. adults between March 2022 - October 2023. Prevalence of at-home RDT use and healthcare seeking following a positive or negative RDT result was estimated by participant vaccination status and socio-demographic characteristics. At true values ranging from 5% to 95%, we defined bias as the difference between the observed and true . Among 1,918 symptomatic adults, prevalence of at-home RDT use was higher among vaccinated (37%) versus unvaccinated (22%) participants. At-home RDT use was associated with seeking care, and participants reporting positive RDT were more likely than those reporting negative RDT to have sought care when ill. In primary analyses, we observed downward bias in VE estimates that increased in magnitude when true was low. Variations in proportions of vaccination, at-home RDT use and healthcare seeking by socio-demographic characteristics may impact VE estimates. Further evaluation of potential impact of at-home RDT use on VE estimates is warranted.

MeSH

Research Design, Bias, Vaccines, Covid-19 Vaccines, Vaccination, Covid-19, Demography