The rate at which cancer patients need additional COVID-19 boosters depends on the treatment they are receiving, researchers report.
For many, the threat of the COVID-19 pandemic seems over. However, for patients whose immune systems are compromised by cancer or by cancer therapies, fear of COVID-19 infection and severe disease remains very real.
Currently, guidance from the Centers for Disease Control and Prevention recommends that immunocompromised patients receive COVID-19 booster shots “as needed.” While this flexibility is useful for patients with complex medical conditions, it lacks more specific guidance as to when additional COVID-19 boosters would be most effective.
The new study, published in the Journal of the National Cancer Institute, provides this critically needed information.
The study quantifies the long-term likelihood of future infection among cancer patients undergoing various common therapies after they received updated Pfizer vaccine booster shots.
According to the research, increased boosting among cancer patients provides benefits similar to those obtained by non-cancer patients. The study predicts that one out of every three people who forgo boosting will be infected within two years. In contrast, boosting every six months reduces that risk to 1 in 20.
“It turns out that most cancer patients are protected nearly as well as the non-cancer population by COVID-19 boosting,” says lead author Jeffrey Townsend , a professor in the Yale University School of Public Health. “But there is a big exception.”
“Some cancer therapies directly attack immune cells,” says co-lead author Alex Dornburg, an assistant professor at the University of North Carolina at Charlotte. “This is great for battling blood cancers such as some lymphomas, but the death of immune cells also opens a window not only for COVID-19 infection, but for severe infection.”
For those cancer patients whose therapies directly affect the immune response, a much higher frequency of boosting could be very beneficial, the researchers say. With annual boosting, one out of every three patients on these therapies would still be vulnerable to contracting COVID-19 within two years without other interventions. Boosting every three months cuts this risk almost in half, the study says.
The researchers’ data-driven model of infection risks over time takes advantage of the large number of immunological studies of SARS-CoV-2 (the virus that causes COVID-19) and other coronaviruses. The extensive data available enabled them to assess the long-term risks of infection at a range of frequencies of boosting.
“These results are based on a typical patient with a typical immune response receiving common therapies,” Townsend says. “It remains the case that every patient may have mitigating factors that doctors must consider when advising whether and when an additional COVID-19 booster schedule may be appropriate.”
“Fears of severe COVID-19 are not restricted to cancer patients.” Dornburg says. “We hope to develop similar analyses that provide guidance to protect other patients who are especially vulnerable.”
The National Science Foundation funded the work.
Source: Yale University