Post-vaccination antibodies in people who’ve had COVID-19

People who’ve had COVID-19 and then receive the vaccine mount higher antibody responses after one dose than COVID-19-naive people mount after two doses, suggests a study posted on the preprint server medRxiv. Researchers studied 109 vaccine recipients, 38% of whom were seropositive for SARS-CoV-2 at the time of vaccination. They found that median antibody titers among seropositive vaccinees after their first dose were over ten times higher than titers among seronegative vaccinees after their second dose. Seropositive vaccinees also had more systemic side effects, like fatigue and headache. The researchers note that long-term follow-up is needed to see whether the observed immune responses last. One of the researchers told the New York Times, “I think one vaccination should be sufficient [in those who’ve had COVID-19]. … This would also spare individuals from unnecessary pain when getting the second dose and it would free up additional vaccine doses.”

medRxiv study on antibody responses (not peer-reviewed) 

New York Times story on post-vaccine antibody responses