Cancer patients are still susceptible to breakthrough COVID-19 infection after vaccination and most experience severe outcomes as a result of a review of patient data from the international COVID-19 and Cancer Consortium (CCC19) registry.
Of 54 fully vaccinated patients with COVID-19 and cancer, 35 (65 percent) were hospitalized, 10 (19 percent) were admitted to the intensive care unit or required mechanical ventilation and 7 (13 7 %) died within 30 days.
The study didn’t measure the incidence of breakthrough infections among vaccination-free cancer patients, but the results do emphasize the necessity to keep vigilance up in securing this vulnerable group by vaccinating close family members or administering boosters, as well as social distancing.
“Overall, vaccination remains an invaluable strategy in protecting vulnerable populations, including those suffering from cancer, from COVID-19. However, cancer patients who develop breakthrough infection despite complete vaccination are at risk of sustaining severe complications,” the authors wrote.
The Annals of Oncology December 24, 2018, was published as a pre-proof, but has not yet been peer-reviewed. It analyzed the registry data of 1787 individuals diagnosed with invasive cancer or confirmed in a laboratory COVID-19. This was before COVID vaccination was widely available. Of these 1656 (93 percent) were unvaccinated, while 77 (4 percent) were partially vaccinated, and 54 (3%) were considered fully vaccine-free at the time of COVID-19 infection.
52 of the patients who had been fully vaccinated with breakthrough infections (96 percent) required admission. Nearly 1 in 5 required ventilation or were admitted to the ICU and 13% died within 30 working days.
The investigators state that “comparable rates were observed” in the unvaccinated population. They also note that there was no statistically significant difference in the 30-day mortality between unvaccinated and fully vaccinated patients (adjusted odds ratio [aOR 1,08).
Patients who are not vaccinated are more likely to die from lymphopenia (aOR 1.68) and co-morbidities (1.66 – 2.10) and worse performance (4.34 – 2.26). Baseline cancer status (active/progressing vs. not active/advancing, aOR 6.07).
After adjustment for cofounders (aORs 1.13 and 1.25 respectively), there were no significant differences in ICU, mechanical ventilation or hospitalization rates between the unvaccinated and vaccinated cohorts.
Patients with a hematologic malignancy as the underlying were more common among patients who received breakthrough COVID-19 (35 percent vs 20%). As compared to those with solid cancers with cancers of the hematologic type also had higher rates of ICU admission, machinal ventilation, and hospitalization.
The authors point out that this finding “confirms the fact that these patients could have a reduced immune response to vaccines secondary to disease or treatment”.
Although the investigators did not examine the risk of a the virus spreading post-vaccination, recent research indicates that receiving a COVID-19 booster increases antibody levels among patients with cancer under active treatment, which could offer an additional level of protection against the virus.
The authors recommend that “a mitigation strategy that involves vaccination of close contacts as well as boosters, social distancing, and mask-wearing publicly should be continued for the foreseeable future” because of the significant chance of breakthrough infections and serious outcomes in cancer patients. However, “additional research is needed to further categorize the patients who remain at risk of symptomatic COVID-19 following vaccination, and tests that can lower the risk.”
These findings are based on an initial proof that hasn’t been peer-reviewed nor published. First author A.L. Schmidt, MD, reported nonfinancial support from Astellas and non-financial support from Pfizer, outside the submitted work. Other co-authors reported a range of disclosures, too. The complete list of disclosures is available in the original article.
Annals Onc. Online publication on December 24 2021, a pre-proof. Full Text
Sharon Worcester is an award-winning medical journalist at MDedge News, part of the Medscape Professional Network
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