TY - JOUR
T1 - Effect of vaccination on household transmission of SARS-CoV-2 Delta variant of concern
AU - Lyngse, Frederik Plesner
AU - Mølbak, Kåre
AU - Denwood, Matt
AU - Christiansen, Lasse Engbo
AU - Møller, Camilla Holten
AU - Rasmussen, Morten
AU - Cohen, Arieh Sierra
AU - Stegger, Marc
AU - Fonager, Jannik
AU - Sieber, Raphael Niklaus
AU - Ellegaard, Kirsten Maren
AU - Nielsen, Claus
AU - Kirkeby, Carsten Thure
N1 - Publisher Copyright:
© 2022, The Author(s).
PY - 2022
Y1 - 2022
N2 - Effective vaccines protect individuals by not only reducing the susceptibility to infection, but also reducing the infectiousness of breakthrough infections in vaccinated cases. To disentangle the vaccine effectiveness against susceptibility to infection (VES) and vaccine effectiveness against infectiousness (VEI), we took advantage of Danish national data comprising 24,693 households with a primary case of SARS-CoV-2 infection (Delta Variant of Concern, 2021) including 53,584 household contacts. In this setting, we estimated VES as 61% (95%-CI: 59-63), when the primary case was unvaccinated, and VEI as 31% (95%-CI: 26-36), when the household contact was unvaccinated. Furthermore, unvaccinated secondary cases with an infection exhibited a three-fold higher viral load compared to fully vaccinated secondary cases with a breakthrough infection. Our results demonstrate that vaccinations reduce susceptibility to infection as well as infectiousness, which should be considered by policy makers when seeking to understand the public health impact of vaccination against transmission of SARS-CoV-2.
AB - Effective vaccines protect individuals by not only reducing the susceptibility to infection, but also reducing the infectiousness of breakthrough infections in vaccinated cases. To disentangle the vaccine effectiveness against susceptibility to infection (VES) and vaccine effectiveness against infectiousness (VEI), we took advantage of Danish national data comprising 24,693 households with a primary case of SARS-CoV-2 infection (Delta Variant of Concern, 2021) including 53,584 household contacts. In this setting, we estimated VES as 61% (95%-CI: 59-63), when the primary case was unvaccinated, and VEI as 31% (95%-CI: 26-36), when the household contact was unvaccinated. Furthermore, unvaccinated secondary cases with an infection exhibited a three-fold higher viral load compared to fully vaccinated secondary cases with a breakthrough infection. Our results demonstrate that vaccinations reduce susceptibility to infection as well as infectiousness, which should be considered by policy makers when seeking to understand the public health impact of vaccination against transmission of SARS-CoV-2.
U2 - 10.1038/s41467-022-31494-y
DO - 10.1038/s41467-022-31494-y
M3 - Journal article
C2 - 35773247
AN - SCOPUS:85133121692
VL - 13
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 3764
ER -