BackgroundDetermining the vaccine effectiveness (VE) is an important part of studying every new vaccine. Test-negative case–control (TNCC) studies have recently been used to determine theVE. However, the estimatedVEderived from a TNCC design depends on the test sensitivity and specificity. Herein, a method for correction of the value ofVEderived from a TNCC study is presented.MethodsAn analytical method is presented to compute the correctedVEbased on the sensitivity and specificity of the diagnostic test utilized. To show the application of the method proposed, a hypothetical TNCC study is presented. In this in silico study, 100 000 individuals referring to a healthcare system for COVID-19-like illness were tested with diagnostic tests with sensitivities of 0.6, 0.8, and 1.0, and specificities ranging from 0.85 to 1.00. A vaccination coverage of 60%, an attack rate of 0.05 for COVID-19 in unvaccinated group, and a trueVEof 0.70, were assumed. In this simulation, a COVID-19-like illness with an attack rate of 0.30 could also affect all the studied population regardless of their vaccination status.ResultsThe observedVEranged from 0.11 (computed for a test sensitivity of 0.60 and specificity of 0.85) to 0.71 (computed for a test sensitivity and specificity of 1.0). The mean computed correctedVEderived from the proposed method was 0.71 (the standard deviation of 0.02).ConclusionsThe observedVEderived from TNCC studies can be corrected easily. An acceptable estimate forVEcan be computed regardless of the diagnostic test sensitivity and specificity used in the study.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12874-023-01962-0.