|LETTER TO EDITOR
|Year : 2023 | Volume
| Issue : 1 | Page : 75
Positive predictive value of SARS-CoV-2 spike protein antibody test after COVID-19 vaccination policies
Pathum Sookaromdee1, Viroj Wiwanitkit2
1 Private Academic Consultant, Bangkok, Thailand
2 Department of Community Medicine, Dr. DY Patil University, Pune, Maharashtra, India
|Date of Submission||25-Jun-2021|
|Date of Acceptance||28-Apr-2022|
|Date of Web Publication||16-Jun-2023|
Private Academic Consultant, Bangkok
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sookaromdee P, Wiwanitkit V. Positive predictive value of SARS-CoV-2 spike protein antibody test after COVID-19 vaccination policies. Int J Prev Med 2023;14:75
|How to cite this URL:|
Sookaromdee P, Wiwanitkit V. Positive predictive value of SARS-CoV-2 spike protein antibody test after COVID-19 vaccination policies. Int J Prev Med [serial online] 2023 [cited 2023 Sep 27];14:75. Available from: https://www.ijpvmjournal.net/text.asp?2023/14/1/75/378883
Mendicino and Moretti provided very useful ideas on using “tests for the detection of antibodies to SARS-CoV-2.” Mendicino and Moretti discussed on effect of local prevalence of coronavirus disease (COVID) on diagnostic property of the test and concluded that “knowledge about the advantages and limitations of each test will help to select the most appropriate one to each clinical and epidemiological situation, and to an adequate interpretation of the results.” It is agreeable that the positive predictive value (PPV) of a diagnostic test is associated with the prevalence of disease. However, in case that there is an additional confounding factor leading to the change of diagnostic sensitivity and specificity, the change of PPV test is expected.
At present, COVID-19 vaccination is the main disease prevention policy in any country. A vaccination can induce antibody generation and the generated antibody can result in a false-positive case result for an antibody diagnostic test for diagnosing COVID-19. Here, the authors tried to additionally assess the change of PPV of SARS-CoV-2 spike protein antibody test after COVID-19 vaccination policies. As noted by Mendicino and Moretti, the sensitivity and specificity of available immunoassays for diagnosis of COVID-19 are 90% and 97%, respectively., Using an assumption that a COVID-19 vaccine is very effective and can generate 100% of antibody, the percentage of vaccine recipient population will be a determinant for false positive.
Here, the authors use those data for simulation on two scenarios as proposed by Mendicino and Moretti, giving local prevalence equal to 0.3% and 30%, respectively. Based on a clinical mathematical model, expected PPV of COVID-19 immunoassay in situation with different percentage of vaccinated population is shown in [Table 1]. In a setting with low prevalence, the background PPV in case with no vaccination is poor and it becomes poorer when there is an expansion of the vaccination coverage rate. Similar trend is also observed in high prevalence setting. The antibody immunoassay for SARS-CoV-2 spike protein antibody test will play very limited role when COVID-19 vaccination successfully covers population.
|Table 1: Expected PPV of COVID-19 immunoassay in situation with different percentage of vaccinated population|
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Conflicts of interest
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| References|| |
Mendicino DA, Moretti ER. Tests for the detection of antibodies to SARS-CoV-2: Importance of the critical professional interpretation. Int J Prev Med 2021;12:61. [Full text]
Castro R, Luz PM, Wakimoto MD, Veloso VG, Grinsztejn B, Perazzo H. COVID-19: A meta-analysis of diagnostic test accuracy of commercial assays registered in Brazil. Braz J Infect Dis 2020;24:180-7.