Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Mar 15;12(3):719.
doi: 10.3390/diagnostics12030719.

The Effect of Varying Interval Definitions on the Prevalence of SARS-CoV-2 Reinfections: A Retrospective Cross-Sectional Cohort Study

Sjoerd M Euser  1 , Tieme Weenink  1 , Jan M Prins  2 , Milly Haverkort  3 , Irene Manders  1 , Steven van Lelyveld  4 , Bjorn L Herpers  1 , Jan Sinnige  1 , Jayant Kalpoe  1 , Dominic Snijders  4 , James Cohen Stuart  5 , Fred Slijkerman Megelink  6 , Erik Kapteijns  7 , Jeroen den Boer  1 , Alex Wagemakers  1 , Dennis Souverein  1
Affiliations

The Effect of Varying Interval Definitions on the Prevalence of SARS-CoV-2 Reinfections: A Retrospective Cross-Sectional Cohort Study

Sjoerd M Euser et al. Diagnostics (Basel). .

Abstract

Background: We assessed the SARS-CoV-2 reinfection rate in a large patient cohort, and evaluated the effect of varying time intervals between two positive tests on assumed reinfection rates using viral load data.

Methods: All positive SARS-CoV-2 samples collected between 1 March 2020 and 1 August 2021 from a laboratory in the region Kennemerland, the Netherlands, were included. The reinfection rate was analyzed using different time intervals between two positive tests varying between 2 and 16 weeks. SARS-CoV-2 PCR crossing point (Cp) values were used to estimate viral loads.

Results: In total, 679,513 samples were analyzed, of which 53,366 tests (7.9%) were SARS-CoV-2 positive. The number of reinfections varied between 260 (0.52%) for an interval of 2 weeks, 89 (0.19%) for 4 weeks, 52 (0.11%) for 8 weeks, and 37 (0.09%) for a minimum interval of 16 weeks between positive tests. The median Cp-value (IQR) in the second positive samples decreased when a longer interval was chosen, but stabilized from week 8 onwards.

Conclusions: Although the calculated reinfection prevalence was relatively low (0.11% for the 8-week time interval), choosing a different minimum interval between two positive tests resulted in major differences in reinfection rates. As reinfection Cp-values stabilized after 8 weeks, we hypothesize this interval to best reflect novel infection rather than persistent shedding.

Keywords: COVID-19; Cp-value; SARS-CoV-2; re-infection.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Cumulative number of reinfections according to different time intervals between two positive tests.
Figure 2
Figure 2
Median Cp-values of first and second positive RT-PCR tests of reinfection cases according to different time intervals between two positive tests.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Gousseff M., Penot P., Gallay L., Batisse D., Benech N., Bouiller K., Collarino R., Conrad A., Slama D., Joseph C., et al. Clinical recurrences of COVID-19 symptoms after recovery: Viral relapse, reinfection or inflammatory rebound? J. Infect. 2020;81:816–846. doi: 10.1016/j.jinf.2020.06.073. - DOI - PMC - PubMed
    1. Dao T.L., Hoang V.T., Gautret P. Recurrence of SARS-CoV-2 viral RNA in recovered COVID-19 patients: A narrative review. Eur. J. Clin. Microbiol. Infect. Dis. 2021;40:13–25. doi: 10.1007/s10096-020-04088-z. - DOI - PMC - PubMed
    1. Overbaugh J. Understanding protection from SARS-CoV-2 by studying reinfection. Nat Med. 2020;26:1680–1681. doi: 10.1038/s41591-020-1121-z. - DOI - PubMed
    1. To K.K., Hung I.F., Ip J.D., Chu A.W., Chan W.M., Tam A.R., Fong C.H., Yuan S., Tsoi H.W., Ng A.C., et al. Coronavirus Disease 2019 (COVID-19) Re-infection by a Phylogenetically Distinct Severe Acute Respiratory Syndrome Coronavirus 2 Strain Confirmed by Whole Genome Sequencing. Clin. Infect. Dis. 2021;73:e2946–e2951. doi: 10.1093/cid/ciaa1275. - DOI - PMC - PubMed
    1. Gupta V., Bhoyar R.C., Jain A., Srivastava S., Upadhayay R., Imran M., Jolly B., Divakar M.K., Sharma D., Sehgal P., et al. Asymptomatic Reinfection in 2 Healthcare Workers from India with Genetically Distinct Severe Acute Respiratory Syndrome Coronavirus 2. Clin. Infect. Dis. 2021;73:e2823–e2825. doi: 10.1093/cid/ciaa1451. - DOI - PMC - PubMed