Immune response to COVID-19 strengthens over time: Study

Immunity from COVID-19 appears to gather strength with more time between vaccination and infection, a new laboratory study from researchers at Oregon Health & Science University suggests. The findings carry implications for vaccine recommendations as the pandemic transitions to an endemic state.

Researchers measured the antibody response in blood samples for a group of people who gained so-called “hybrid immunity” through two means: either vaccination followed by a breakthrough infection, or by getting vaccinated after contracting COVID-19. They measured the immune response in blood samples of 96 generally healthy OHSU employees and found that the immune response was uniformly stronger the longer the time period between vaccination and infection. The longest interval measured was 404 days.

Their findings suggest that vaccine boosters should be spaced no more frequently than a year apart, at least among healthy people. Their findings suggest that the magnitude, potency and breadth of hybrid immune response all increased with a longer time period between exposure to the virus — whether through vaccination or natural infection.

Further, the research team found that it didn’t matter whether someone developed hybrid immunity by getting vaccinated after contracting COVID-19 or after a breakthrough infection following vaccination. Both groups developed an equally potent immune response.The findings suggest long-lasting potency of so-called “memory cells.”

Reference:

Fikadu Tafesse et al,An extended interval between vaccination and infection enhances hybrid immunity against SARS-CoV-2 variants,JCI Insight,doi 10.1172/jci.insight.165265