Durability of antibodies after COVID-19 vaccination in HCWs with, without prior infection

Editor's Note

This study from Johns Hopkins University, Baltimore, finds that healthcare workers (HCWs) with prior COVID-19 infection followed by 2 doses of an mRNA vaccine developed higher spike antibody measurements than HCWs with vaccination alone.

Of 1,960 HCWs analyzed, 73 (3.7%) had evidence of previous COVID-19 infection. Among those, the adjusted median antibody measurements were 8.69 at 1 month, 7.28 at 3 months, and 4.55 at 6 months after vaccination.

Compared with HCWs without previous COVID-19 infection, those with previous infection maintained higher postvaccination adjusted median antibody measurements by an absolute difference of 1.25 at 1 month, 1.42 at 3 months, and 2.56 at 6 months.

HCWs with confirmed COVID-19 infection more than 90 days before vaccination had higher postvaccination adjusted antibody measurements, compared with HCWs with confirmed COVID-19 infection less than or equal to 90 days before vaccination, of 10.52 at 1 month and 9.31 at 3 months.

Results show that a longer interval between infection and fist vaccine dose may enhance the antibody response, the authors say.