As households are the site of most SARS-CoV-2 transmission globally, the new study included 440 households in London and Bolton doing PCR Covid tests between September 2020 and September 2021.
The results revealed that even with no or few symptoms, the chance of transmitting the virus to other unvaccinated housemates is about two in five or 38 percent. This drops to one in four, or 25 percent if housemates are also fully vaccinated.
“This finding indicates that breakthrough infections in fully vaccinated people can efficiently transmit infection in the household setting,” said corresponding author Prof Ajit Lalvani, National Heart and Lung Institute, Imperial College London, UK.
Fully vaccinated individuals with breakthrough infections seem to have peak viral load similar to unvaccinated cases and can efficiently transmit infection in household settings, including fully vaccinated contacts. Host-virus interactions early in infection may shape the entire viral trajectory.
Further, the study showed that the susceptibility to infection increases already within a few months after the second vaccine dose, pressing the need for booster shots.
This study also suggests that continued public health and social measures to curb transmissions such as mask-wearing, social distancing, and testing remain important, even in vaccinated individuals.
Source: Medindia
