Among cancer patients with solid tumors, the response to the COVID-19 vaccine 6 months after receiving a second dose was as good as that of the general population, according to new findings from a case-control study.
The BNT162b2, or Pfizer-BioNTech, vaccine (Comirnaty) was previously shown to have good short-term efficacy, immunogenicity, and safety in cancer patients with solid tumors, but little is known about longer-term efficacy in this population, say the investigators.
They assessed responses 6 months after a second dose of the vaccine.
Serologic tests showed that 122 of 154 patients with solid tumors who were actively undergoing cancer treatment (79%) and 114 of 135 age-matched health care workers who served as control persons (84%) were seropositive at 6 months (P = .32).
Most (81%) of the patients with cancer who were seronegative were receiving chemotherapy, the researchers report.
One case of severe COVID-19 that required hospitalization occurred among the solid-tumor group; none occurred among the control persons, they also note.
The findings were published online on Sept. 2 in Cancer Discovery.
“In our study we saw that in all outcomes, including immunogenicity, infectivity rate throughout the 6-month period, and safety, patients with solid tumors depicted a similar trend as the general population,” commented lead author Irit Ben-Aharon, MD, PhD, director of the division of oncology at Rambam Health Care Campus, Haifa, Israel, in an American Association for Cancer Research press statement.
However, she and her coauthors stressed the importance of continuing to follow guidance, such as social distancing and mask wearing, for reducing COVID-19 transmission. “Due to uncertainty of the extended efficacy of the vaccine in the general population and recent reports on rising infection rates among vaccinated individuals, adherence to health care risk reduction recommendations is cardinal,” they write.
The mean age of the control persons in the study was 63 years, and the mean age of the case patients was 66 years. The most common cancers were gastrointestinal (36%), lung (23%), breast (17%), and genitourinary (11%). Treatment protocols included chemotherapy (62%), biological agents (36%), and immunotherapy (30%). Some patients received more than one type of treatment.
All of the reported adverse effects associated with vaccination had resolved at the time of follow-up.
These data can “help inform recommendations surrounding the prioritization of different groups for booster vaccines,” Dr. Ben-Aharon adds.
In fact, recently updated guidelines from the National Comprehensive Cancer Network state that cancer patients with solid tumors who are receiving treatment within 1 year of their initial vaccine dose should be prioritized for a booster vaccine.
The study was partially supported by the Israel Cancer Research Fund. Serologic testing of the control cohort was supported by the Ministry of Health, Israel. The authors have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.