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. 2021 May 13;32(4):508–517. doi: 10.1097/EDE.0000000000001366

TABLE 6.

Contingency Table for Traditional Case-control and Test-negative Design Studies With Differential Risk of Current and Prior Infection Among the Vaccinated and Unvaccinated

Exposure Outcome
Test-positive Case (Symptomatic) Community Control (Asymptomatic) Test-negative Control (Symptomatic)
Vaccinated graphic file with name ede-32-508-i129.jpg graphic file with name ede-32-508-i130.jpg graphic file with name ede-32-508-i131.jpg
Unvaccinated graphic file with name ede-32-508-i132.jpg graphic file with name ede-32-508-i133.jpg graphic file with name ede-32-508-i134.jpg

Contents of the table are probabilities of the various listed outcomes, accounting for vaccinated or unvaccinated status. Parameters: Inline graphic, proportion of the population vaccinated; a, prevalence of SARS-CoV-2 infection; d, risk of COVID-19 among those with SARS-CoV-2 infection; k, risk of symptoms due to causes other than SARS-CoV-2 infection; Inline graphic, relative risk of SARS-CoV-2, given vaccination; Inline graphic, relative risk of COVID-19, among those with SARS-CoV-2 infection, given vaccination; Inline graphic, relative risk of exposure or infection among vaccinated versus unvaccinated individuals attributable to factors other than vaccine-conferred immunity; Inline graphic, proportion of vaccinated individuals who remain uninfected; Inline graphic, proportion of unvaccinated individuals who remain uninfected (Table 1).