tetano
Editor, Senior Moderator
Int J Epidemiol
. 2026 Oct 14;55(6):dyag226.
doi: 10.1093/ije/dyag226.
Ryan E Wiegand 1 , Gordana Derado 1 , Allison Avrich Ciesla 1 2 , Saba A Qasmieh 3 4 , Jill M Ferdinands 5 , Brendan Flannery 5 , Ruth Link-Gelles 1 6
Affiliations Expand
Background: Use of rapid diagnostic tests (RDTs) may bias vaccine effectiveness (VE) estimates from test-negative design (TND) studies. We conducted individual-level simulations using national, US COVID-19 surveillance data to assess potential bias at varying likelihoods of visiting a healthcare facility and prevalence of RDT use.
Methods: Twenty-one scenarios that varied the probabilities of visiting a healthcare facility and RDT use by vaccination status were simulated. VE was calculated as 100 × (1 - odds ratio), comparing the odds of symptomatic SARS-CoV-2 infection between vaccinated and unvaccinated groups of people. VE estimates were compared to VE estimates from simulations without RDT testing to calculate the bias in percentage points (pp).
Results: VE was underestimated when either vaccinated people were more likely (probability of .5) than unvaccinated people (probability of .3) to visit a healthcare facility after a positive RDT [-5.8%age points (pp); 95% uncertainty interval (UI): -9.1, -2.4] or unvaccinated people were more likely than vaccinated people to visit a healthcare facility after a negative RDT (bias = -6.1 pp; UI: -9.9, -2.5). Conversely, VE was overestimated when either vaccinated people were more likely than unvaccinated people to visit a healthcare facility after a negative RDT (bias = 5.2; UI: 2.4, 7.7) or unvaccinated people were more likely than vaccinated people to visit a healthcare facility after a positive RDT (bias = 8.4 pp; UI: 5.6, 11.3).
Conclusion: VE estimates against symptomatic SARS-CoV-2 infection from a TND may be under- or overestimated, depending on differences in RDT usage between vaccination groups.
Keywords: rapid diagnostic test; test-negative design; vaccine effectiveness.
. 2026 Oct 14;55(6):dyag226.
doi: 10.1093/ije/dyag226.
Differences in SARS-CoV-2 rapid diagnostic testing usage by COVID-19 vaccination status can bias vaccine effectiveness estimates against symptomatic SARS-CoV-2 infection from a test-negative design
Ryan E Wiegand 1 , Gordana Derado 1 , Allison Avrich Ciesla 1 2 , Saba A Qasmieh 3 4 , Jill M Ferdinands 5 , Brendan Flannery 5 , Ruth Link-Gelles 1 6
Affiliations Expand
- PMID: 42909463
- DOI: 10.1093/ije/dyag226
Abstract
Background: Use of rapid diagnostic tests (RDTs) may bias vaccine effectiveness (VE) estimates from test-negative design (TND) studies. We conducted individual-level simulations using national, US COVID-19 surveillance data to assess potential bias at varying likelihoods of visiting a healthcare facility and prevalence of RDT use.
Methods: Twenty-one scenarios that varied the probabilities of visiting a healthcare facility and RDT use by vaccination status were simulated. VE was calculated as 100 × (1 - odds ratio), comparing the odds of symptomatic SARS-CoV-2 infection between vaccinated and unvaccinated groups of people. VE estimates were compared to VE estimates from simulations without RDT testing to calculate the bias in percentage points (pp).
Results: VE was underestimated when either vaccinated people were more likely (probability of .5) than unvaccinated people (probability of .3) to visit a healthcare facility after a positive RDT [-5.8%age points (pp); 95% uncertainty interval (UI): -9.1, -2.4] or unvaccinated people were more likely than vaccinated people to visit a healthcare facility after a negative RDT (bias = -6.1 pp; UI: -9.9, -2.5). Conversely, VE was overestimated when either vaccinated people were more likely than unvaccinated people to visit a healthcare facility after a negative RDT (bias = 5.2; UI: 2.4, 7.7) or unvaccinated people were more likely than vaccinated people to visit a healthcare facility after a positive RDT (bias = 8.4 pp; UI: 5.6, 11.3).
Conclusion: VE estimates against symptomatic SARS-CoV-2 infection from a TND may be under- or overestimated, depending on differences in RDT usage between vaccination groups.
Keywords: rapid diagnostic test; test-negative design; vaccine effectiveness.