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

TABLE 5.

Contingency Table for Traditional Case-control and Test-negative Design Studies With Differential Healthcare-seeking Among the Vaccinated and Unvaccinated

Exposure Outcome
Test-positive Case (Symptomatic, Healthcare Sought) Community Control (Healthcare Not Sought) Test-negative Control (Symptomatic, Healthcare Sought)
Vaccinated graphic file with name ede-32-508-i109.jpg graphic file with name ede-32-508-i110.jpg graphic file with name ede-32-508-i111.jpg
Unvaccinated graphic file with name ede-32-508-i112.jpg graphic file with name ede-32-508-i113.jpg graphic file with name ede-32-508-i114.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, probability of testing for symptomatic vaccinated individuals; Inline graphic, probability of testing for symptomatic unvaccinated individuals (Table 1).