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29-06-2021 | Oncology | News | Article

Prior COVID-19 infection strengthens Pfizer vaccine response in cancer patients

Author: Laura Cowen

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

29 June 2021: The coronavirus pandemic is affecting all healthcare professionals across the globe. Medicine Matters’ focus, in this difficult time, is the dissemination of the latest data to support you in your research and clinical practice, based on the scientific literature. We will update the information we provide on the site, as the data are published. However, please refer to your own professional and governmental guidelines for the latest guidance in your own country.

Eur J Cancer 2021; doi:10.1016/j.ejca.2021.05.036

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