Two studies show higher anti-S titers in those with previous infection and very strong T-cell responses
TUESDAY, March 2, 2021 (HealthDay News) — Individuals with previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection generate strong responses to one dose of the BNT162b2 vaccine, according to two research letters published online Feb. 25 in The Lancet.
Maria Prendecki, Ph.D., from Imperial College London, and colleagues investigated immunological responses to single-dose BNT162b2 among 72 health care workers (HCWs) who were vaccinated between Dec. 23 and 31, 2020. Twenty-one of the participants had evidence of previous SARS-CoV-2 infection and 51 were defined as infection-naive. The researchers found that postvaccination, anti-S titers were significantly higher in individuals with previous natural infection than infection-naive participants. In a subset of participants, in those with previous exposure, the vaccine induced very strong neutralizing antibody titers; vaccination induced detectable neutralizing antibodies in infection-naive individuals, but titers were lower. Those with evidence of previous SARS-CoV-2 infection at baseline mounted very strong T-cell responses to spike peptides; these responses were significantly weaker in the infection-naive group.
Charlotte Manisty, M.D., Ph.D., also from University College London, and colleagues undertook a nested case-control analysis of 51 participants of an ongoing longitudinal observational study of HCWs, 24 of whom had previous laboratory-confirmed mild or asymptomatic SARS-CoV-2 infection. All participants received their first dose of the BNT162b2 mRNA COVID-19 vaccine and were tested 19 to 29 days after. The researchers found that vaccination increased anti-S titers more than 140-fold from peak prevaccine levels among those with a previous SARS-CoV-2 infection. This increase was at least one order of magnitude greater than reported after a conventional prime-boost vaccine strategy in previously uninfected individuals.
“Our findings provide a rationale for serology-based vaccine dosing to maximize coverage and impact,” Manisty and colleagues write.
Several authors from both studies disclosed financial ties to Oxford Immunotec.
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