Vaccine After COVID-19 Infection Boosts Immune Response, Study Finds

Tara Haelle

November 01, 2021

People who already have had COVID-19 may have more reason to get vaccinated, with new findings suggesting that vaccination after infection can boost protection.

Under viral threat, the body first uses B cells to make antibodies against the invader, a process that can take up to 2 weeks. The immune system simultaneously creates memory B cells that can recognize the virus if it reappears and rapidly mounts a powerful secondary response.

In a series of  shots, the first dose triggers the primary response. The follow-up doses activate the memory B cells, strengthening defenses against the pathogen.

These new results, published in Cell Reports , show that a SARS-CoV-2 infection, like a first vaccine dose, will elicit the primary response, as expected.

The researchers also found that a vaccine after the infection can set off the secondary memory B cell response, enhancing immune protection for those who already have had COVID-19. In fact, this secondary reaction exceeded responses after two vaccine doses in those with no history of SARS-CoV-2 infection.

The findings suggest that vaccination is particularly valuable for people who have already had COVID-19, ensuring a robust immune reaction if the virus finds them again.


Cell Reports: "High-affinity memory B cells induced by SARS-CoV-2 infection produce more plasmablasts and atypical memory B cells than those primed by mRNA vaccines.”

Wiley Online Library: “Immune Responses: Primary and Secondary."


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