What about asymptomatic infections?
As they worked, the scientists also found markers of previous SARS-CoV-2 infection in about 30% of study volunteers who had never shown COVID-19 symptoms. These volunteers appeared to have contracted asymptomatic cases of COVID-19 at some point earlier in the pandemic.
“Our study suggests most people who never thought they got a breakthrough infection actually did,” says Grifoni. “The majority of the population appears to be affected by a combination of vaccination and one or more breakthrough infections.”
How COVID-19 ‘breakthrough’ infections alter your immune cells (medicalxpress.com)
The main thrust of the study is that T- and B-cell immunity is particularly strong in those who were vaccinated and then had Covid-19 afterwards, and appears to be better than having vaccination alone.
