Influence of past infection with SARS-CoV-2 on the response to the BNT162b2 mRNA vaccine in health care workers: Kinetics and durability of the humoral immune response.
EBioMedicine 2021;
73:103656. [PMID:
34740112 PMCID:
PMC8556513 DOI:
10.1016/j.ebiom.2021.103656]
[Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND
SARS-CoV-2 vaccines are an invaluable resource against COVID-19. Current vaccine shortage makes it necessary to prioritize distribution to the most appropriate segments of the population.
METHODS
This is a prospective cohort study of 63 health care workers (HCWs) from a General Hospital. We compared antibody responses to two doses of BNT162b2 mRNA COVID-19 vaccine between HCWs with previous SARS-CoV-2 infection (experienced HCWs) and HCWs without previous infection (naïve HCWs).
FINDINGS
Seven days after the first vaccine dose, HCWs with previous infection experienced a 126-fold increase in antibody levels (p<0·001). However, in the HCW naïve group, response was much lower and only five showed positive antibody levels (>50 AU). After the second dose, no significant increase in antibody levels was found in experienced HCWs, whereas in naïve HCWs, levels increased by 16-fold (p<0·001). Approximately two months post-vaccination, antibody levels were much lower in naïve HCWs compared to experienced HCWs (p<0·001).
INTERPRETATION
The study shows that at least ten months post-COVID-19 infection, the immune system is still capable of producing a rapid and powerful secondary antibody response following one single vaccine dose. Additionally, we found no further improvement in antibody response to the second dose in COVID-19 experienced HCWs. Nonetheless, two months later, antibody levels were still higher for experienced HCWs. These data suggest that immune memory persists in recovered individuals; therefore, the second dose of the COVID-19 vaccine in this group could be postponed until immunization of the remaining population is complete.
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