SSI: “vaccinated people have a higher risk of becoming infected with BA.2 compared to BA.1”
The study finds an overall secondary attack rate of 39% in BA.2 infected households compared to 29% in BA.1 infected households.
When comparing BA.2 relative to BA.1 infected households, there was an increased risk of infection in BA.2 infected households regardless of the vaccination status of the potential secondary case, indicating an inherent increased transmissibility of the BA.2 subvariant.
In addition, comparing the risk of household members being infected in BA.2 relative to BA.1 infected households, was higher in vaccinated and booster vaccinated than in unvaccinated, which suggests immune evasive properties of the BA.2 variant.
