Prior COVID-19 infection strengthens Pfizer vaccine response in cancer patients
medwireNews: A single dose of the Pfizer-BioNTech (BNT162b2) vaccine induces high SARS-CoV-2 antibody levels in people with cancer and prior SARS-CoV-2 infection, but immunogenicity is lower in those without previous infection, research shows.
In spite of this, the majority of individuals with cancer and no history of COVID-19 will be positive for SARS-CoV-2 IgG antibodies following a vaccine boost 3 weeks after the first dose, report Dominic Fong (Franz Tappeiner Hospital, Merano, Italy) and co-authors in the European Journal of Cancer.
Fong and team reviewed data for 89 people with cancer and a history of previous COVID-19 infection (PCR confirmed or serologically detected) and 154 people with cancer but no prior COVID-19, all of whom received the Pfizer COVID-19 messenger RNA vaccine between March and May 2021.
The majority (63.4%) of participants had solid tumors, most commonly breast or gynecologic cancers, followed by urologic cancers, gastrointestinal cancers, and thoracic malignancies, while 36.6% had hematologic cancers.
The researchers found that 61.8% of the people with prior COVID-19 were positive for IgG antibodies against the S1 subunit of the SARS-CoV-2 spike protein (S-IgG) prior to vaccination. A further 21.3% were negative for S-IgG and 16.9% did not have this information available because SARS-CoV-2 infection was detected serologically shortly before vaccination. The latter group were, however, positive for IgG antibodies against the SARS-CoV-2 nucleocapsid protein.
At 3 weeks after the first vaccine dose, 91.0% of patients with prior COVID-19 were positive for S-IgG antibodies. Those who were negative received a second vaccine dose, which increased the seropositivity rate to 96.6% 3 weeks later.
All patients with no history of COVID-19 received two vaccines doses. After the first dose, 61.0% were positive for S-IgG antibodies, with the rate increasing to 85.7% after two doses.
Fong et al also note that the median S-IgG antibody titers were 157.3 times higher after the first vaccine dose in people with versus without prior COVID-19 (15,927 vs 101.2 arbitrary units/mL).
The authors conclude that “[s]creening for S-IgG antibodies may be helpful to further optimize vaccine doses in individuals with or without prior SARS-CoV-2 infection.”
They add: “The duration of antibody response and longitudinal effectiveness of mRNA vaccines in cancer patients need further investigation.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2021 Springer Healthcare Ltd, part of the Springer Nature Group
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