Cancer patients who received the Pfizer-BioNTech COVID-19 vaccine still produce an immune response to the virus four months after their second dose, a new study says. File Photo by Debbie Hill/UPI | License Photo
Aug. 11 (UPI) -- Most people who receive cancer treatment continue to produce antibodies against COVID-19 up to four months after their second dose of the Pfizer-BioNTech vaccine, a study published Wednesday by JAMA Oncology found.
In the study, conducted in Israel, 87% of lung, breast, gastrointestinal, brain and genitourinary cancer patients still had virus antibodies that long after the second vaccination, data showed.
In comparison, 100% of the "control" participants who did not have cancer still were generating antibodies against the coronavirus at four months, the researchers said.
Antibodies are cells produced by the immune system to fight off infections.
"More than 85% [of cancer patients] remain with adequate antibody levels," study co-author Dr. Salomon M. Stemmer told UPI in an email.
It is unclear whether these patients ultimately will require booster doses of the vaccine to maintain immunity, said Stemmer, a professor of oncology at Rabin Medical Center in Petah Tikva.
Many patients with cancer are treated with drugs to boost the immune system help fight off the disease, and the approach, called immunotherapy, could impact the protection provided by COVID-19 vaccines, according to American Cancer Society.
An earlier study by the same team of researchers, published in May by JAMA Oncology, found the Pfizer vaccine still is effective in those receiving treatment for cancer, though they produce a lower immune response than those without the disease.
A separate analysis, also conducted in Israel and published in July by JAMA Oncology, determined that the vaccine, which is the primary one used in Israel, is safe and effective in people with cancer.
Although the two-dose Moderna COVID-19 vaccine was not assessed in any of these studies, the researchers involved believe it would produce roughly the same results, given that it has a similar formulation.
For the most recent study, Stemmer and his colleagues compared the immune responses in 92 cancer patients four months after they received the second dose of the Pfizer-BioNTech vaccine to those of 66 study participants without cancer.
Eighty-three of the 92 cancer patients still had evidence of COVID-19 antibodies 129 days after their second dose, while all of the non-cancer patients did.
Cancer patients on immunotherapy had the lowest antibody levels in the study, according to the researchers.
One patient, who had breast cancer, was negative for COVID-19 antibodies while on immunotherapy, but later tested positive after changing cancer treatments, they said.
Just as in the "general population," it remains to be seen whether cancer patients will need additional doses of the coronavirus vaccines, Stemmer said.
However, based on their findings, the shots still are recommended for these patients, he said.