The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers’ unvaccinated household members

Jussipekka Salo; Milla Hägg; Mika Kortelainen; Tuija Leino; Tanja Saxell; Markku Siikanen; Lauri Sääksvuori

doi:10.1038/s41467-022-28825-4

The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers’ unvaccinated household members

Jussipekka Salo
, Milla Hägg
, Mika Kortelainen
, Tuija Leino
, Tanja Saxell
, Markku Siikanen
, Lauri Sääksvuori^*

^*Corresponding author for this work

Department of Economics

University of Helsinki
VATT Institute for Economic Research
Helsinki Graduate School of Economics
Turku School of Economics
University of Turku
Finnish Institute for Health and Welfare (THL)
Tampere University

Research output: Contribution to journal › Article › Scientific › peer-review

39 Citations (Scopus)

46 Downloads (Pure)

Abstract

Mass vaccination is effective in reducing SARS-CoV-2 infections among vaccinated individuals. However, it remains unclear how effectively COVID-19 vaccines prevent people from spreading the virus to their close contacts. Using nationwide administrative datasets on SARS-CoV-2 infections, vaccination records, demographics, and unique household IDs, we conducted an observational cohort study to estimate the direct and indirect effectiveness of mRNA-based COVID-19 vaccines in reducing infections among vaccinated healthcare workers and their unvaccinated household members. Our estimates for adults imply indirect effectiveness of 39.1% (95% CI: −7.1% to 65.3%) two weeks and 39.0% (95% CI: 18.9% to 54.0%) eight weeks after the second dose. We find that the indirect effect of mRNA-based COVID-19 vaccines within households is smaller for unvaccinated children than for adults and statistically insignificant. Here, we show that mRNA-based COVID-19 vaccines are associated with a reduction in SARS-CoV-2 infections not only among vaccinated individuals but also among unvaccinated adult household members in a real-world setting.

Original language	English
Article number	1162
Pages (from-to)	1-7
Number of pages	7
Journal	Nature Communications
Volume	13
Issue number	1
Early online date	4 Mar 2022
DOIs	https://doi.org/10.1038/s41467-022-28825-4
Publication status	Published - 4 Mar 2022
MoE publication type	A1 Journal article-refereed

Funding

M.K. is supported part by the InFLAMES Flagship Programme of the Academy of Finland (decision number: 33750). L.S. is supported part by the INVEST Flagship Programme of the Academy of Finland (decision number: 320161).

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Access to Document

10.1038/s41467-022-28825-4

The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers’ unvaccinated household membersFinal published version, 545 KBLicence: CC BY

Cite this

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title = "The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers{\textquoteright} unvaccinated household members",

abstract = "Mass vaccination is effective in reducing SARS-CoV-2 infections among vaccinated individuals. However, it remains unclear how effectively COVID-19 vaccines prevent people from spreading the virus to their close contacts. Using nationwide administrative datasets on SARS-CoV-2 infections, vaccination records, demographics, and unique household IDs, we conducted an observational cohort study to estimate the direct and indirect effectiveness of mRNA-based COVID-19 vaccines in reducing infections among vaccinated healthcare workers and their unvaccinated household members. Our estimates for adults imply indirect effectiveness of 39.1\% (95\% CI: −7.1\% to 65.3\%) two weeks and 39.0\% (95\% CI: 18.9\% to 54.0\%) eight weeks after the second dose. We find that the indirect effect of mRNA-based COVID-19 vaccines within households is smaller for unvaccinated children than for adults and statistically insignificant. Here, we show that mRNA-based COVID-19 vaccines are associated with a reduction in SARS-CoV-2 infections not only among vaccinated individuals but also among unvaccinated adult household members in a real-world setting.",

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AU - Siikanen, Markku

AU - Sääksvuori, Lauri

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N2 - Mass vaccination is effective in reducing SARS-CoV-2 infections among vaccinated individuals. However, it remains unclear how effectively COVID-19 vaccines prevent people from spreading the virus to their close contacts. Using nationwide administrative datasets on SARS-CoV-2 infections, vaccination records, demographics, and unique household IDs, we conducted an observational cohort study to estimate the direct and indirect effectiveness of mRNA-based COVID-19 vaccines in reducing infections among vaccinated healthcare workers and their unvaccinated household members. Our estimates for adults imply indirect effectiveness of 39.1% (95% CI: −7.1% to 65.3%) two weeks and 39.0% (95% CI: 18.9% to 54.0%) eight weeks after the second dose. We find that the indirect effect of mRNA-based COVID-19 vaccines within households is smaller for unvaccinated children than for adults and statistically insignificant. Here, we show that mRNA-based COVID-19 vaccines are associated with a reduction in SARS-CoV-2 infections not only among vaccinated individuals but also among unvaccinated adult household members in a real-world setting.

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The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers’ unvaccinated household members

Abstract

Funding

UN SDGs

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The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers’ unvaccinated household members

Abstract

Funding

UN SDGs

Access to Document

Other files and links

Fingerprint

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Aalto University Data Hub

Cite this