medwireNews: People with cancer remain susceptible to severe outcomes after developing breakthrough SARS-CoV-2 infection despite being fully vaccinated, research suggests.
“A mitigation approach that includes vaccination of close contacts, boosters, social distancing, and mask-wearing in public should be continued for the foreseeable future,” advise Toni Choueiri (Dana-Farber Cancer Institute, Boston, Massachusetts, USA) and colleagues in the Annals of Oncology.
They drew on the multi-institutional COVID-19 and Cancer Consortium (CCC19) registry to identify 1787 patients with a current diagnosis or history of solid or hematologic malignancy and a laboratory-confirmed diagnosis of COVID-19 between November 2020 and May 2021.
Three percent of the patients had received two doses of the Pfizer–BioNTech (BNT162b2) or Moderna (mRNA-1273) or a single dose of the Johnson & Johnson (Ad26.COV2.S) vaccine, and were therefore considered fully vaccinated. Four percent were partially vaccinated and 93% were unvaccinated.
In the fully vaccinated group, 65% of patients required hospitalization for COVID-19, 19% needed intensive care or mechanical ventilation, and 13% died within 30 days of diagnosis. The corresponding rates in the unvaccinated group were 50%, 13%, and 10%.
The team then used inverse probability of treatment weighting to adjust for baseline clinical variables, and found no significant difference in the primary endpoint of 30-day all-cause mortality rates between fully vaccinated and unvaccinated patients.
There were also no significant between-group differences with regard to the rates of intensive care/mechanical ventilation use or hospitalization.
Choueiri et al note that “this contrasts with a substantially lower rate of severe outcomes previously identified in vaccinated healthy individuals as opposed to matched unvaccinated controls, outlining the potential vulnerability of patients with cancer.”
Regression analysis identified several parameters significantly associated with an increased risk for 30-day mortality regardless of vaccination status, including active and progressing disease, older age, greater comorbidity burden, worse performance status, and lymphopenia.
“[T]hese established prognostic factors for COVID-19 outcomes remain relevant in defining those patients who may still be at risk of severe outcomes following completion of vaccination,” comment the study authors.
They continue: “Overall, vaccination remains an invaluable strategy in protecting vulnerable populations, including patients with cancer, against COVID-19.
“However, patients with cancer who develop breakthrough infection despite full vaccination remain at risk of severe outcomes and should not be neglected.”
In conclusion, Choueiri and co-authors highlight the need for additional research “to further categorize the patients that remain at risk of symptomatic COVID-19 following vaccination, and test strategies that may reduce this risk,” such as the use of a booster vaccine dose.
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2022 Springer Healthcare Ltd, part of the Springer Nature Group
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