Effect of SARS-CoV-2 prior infection and mRNA vaccination on contagiousness and susceptibility to infection
DOKPE
- Mongin, Denis ORCID University of Geneva
- Bürgisser, Nils ORCID Geneva University Hospitals
- Laurie, Gustavo Geneva Directorate of Health
- Schimmel, Guillaume Geneva Directorate of Health
- Vu, Diem-Lan University of Geneva
- Cullati, Stéphane ORCID University of Fribourg
- Courvoisier, Delphine Sophie University of Geneva
- 2023
Published in:
- Nature Communications. - Springer Nature. - 2023, vol. 14, p. 1-13
English
The immunity conferred by SARS-CoV-2 vaccines and infections reduces the transmission of the virus. To answer how the effect of immunity is shared between a reduction of infectiousness and an increased protection against infection, we examined >50,000 positive cases and >110,000 contacts from Geneva, Switzerland (June 2020 to March 2022). We assessed the association between secondary attack rate (i.e. proportion of new cases among contacts) and immunity from natural infection and/or vaccination, stratifying per four SARS-CoV-2 variants and adjusting for index cases and contacts' socio-demographic characteristics and the propensity of the contacts to be tested. Here we show that immunity protected contacts from infection, rather than reducing infectiousness of index cases. Natural infection conferred the strongest immunity. Hybrid immunity did not surpass recent infection. Although of smaller amplitude, the reduction in infectiousness due to vaccination was less affected by time and by the emergence of new SARS-CoV-2 variants than the susceptibility to infection. These findings support the role of vaccine in reducing infectiousness and underscore the complementary role of interventions reducing SARS-CoV-2 propagation, such as mask use or indoor ventilation.
- Faculty
- Faculté des sciences et de médecine
- Department
- Master en médecine
- Language
-
- English
- Classification
- Pathology, clinical medicine
- License
- CC BY
- Open access status
- gold
- Identifiers
-
- DOI 10.1038/s41467-023-41109-9
- ISSN 2041-1723
- Persistent URL
- https://folia.unifr.ch/unifr/documents/327514
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