The findings have shown that while cancer patients are less likely to build an antibody response against the virus, in principle they are just as likely to build a cellular immune response. Study organizers will continue observing the extent to which this can provide sufficient protection against a severe Covid-19 infection as well as what a response to a potential third "booster vaccination" will be.

Patients with cancer, particularly those under active therapy, are at increased risk of morbidity and mortality when infected with COVID-19 and in this regard, strong protection through vaccination is even more important. Cancer patients, however, are often immunocompromised due to the disease and active therapies and in general, they are unable to build up as good a vaccine response as those who are considered healthy.

Prof. Clemens A. Schmitt, chair in oncology at the JKU Faculty of Medicine, led a research team with members from the Department of Hematology and Internal Oncology (Kepler University Hospital) and conducted a study to determine how well cancer patients respond to the two approved mRNA vaccines, Pfizer/BioNTech and Moderna .

Conducted exclusively at the KUK and included 87 cancer patients as well as an additional 44 control participants, the study featured a unique aspect in which researchers not only recorded the antibody response, but also measured the cellular immune status (meaning so-called T cells) which are specifically directed against the SARS-CoV-2 coronavirus’ spikey surface protein.

The study’s findings show that while cancer patients have less antibody response compared to control subjects, in general, their cellular immune response is just as good. While patients with blood cancers such as lymphoma, leukemia, or multiple myeloma showed a notable lack of antibody and cellular immune response, this was not the case in regard to patients who have more solid tumors, such as organ cancers, even when under active drug therapy. Interestingly, among the control subjects, those who were vaccinated (with or without a prior SARS-CoV-2 infection) had a more robust T-cell response than those who were unvaccinated individuals after having been infected with Covid-19.

Prof. Schmitt finds the study’s findings particularly remarkable in that approximately one-third of cancer patients show either an antibody response only or a T-cell response only and added: "We cannot yet clearly assess what exactly this means when it comes to providing protection against a severe Covid-19 infection so when it comes to cancer patients, on one hand we have conduct frequent testing despite being vaccinated and on the other hand, we have to closely observe whether or not, for example, a sole cell response or an isolated antibody response only to the vaccination is enough to also protect cancer patients well against a severe COVID-19 infection. It will certainly be exciting to see if ‘partial response’ cancer patients benefit from any potential third ‘booster’ shot."

The full study was published online on August 17 as a pre-release version for the renowned journal "Cancer Cell". Please see: *Humoral and Cellular Immune Responses in SARS-CoV-2 mRNA-Vaccinated Patients with Cancer, opens an external URL in a new window