The IGC presented the results regarding the efficacy of Covid-19 vaccines in cancer patients. The study demonstrates that the type of vaccine and therapy adopted influence results in the development of antibodies.
Of 211 cancer patients included in a study coordinated by the Gulbenkian Science Institute (IGC), in Oeiras, and the Hospital Professor Doutor Fernando Fonseca EPE, 43% developed antibodies after the first dose of the vaccine against COVID-19, rising to 83% after complete vaccination.
However, the percentage of patients who developed antibodies during this period varied according to the type of vaccine administered and the type of treatment they were undergoing.
This research is particularly urgent given that it involves a group that is at increased risk of severe illness from COVID-19 and often includes individuals who are undergoing immunosuppressive therapies that compromise the immune system.
Preliminary data from this study revealed that 90.5% of cancer patients inoculated with an mRNA vaccine – either Moderna or Pfizer/BioNTech – had antibodies against SARS-CoV-2 three weeks after complete vaccination. On the other hand, only 65% of patients receiving an adenovirus-based vaccine – AstraZeneca or Jansen – developed immunity.
Previous studies, involving broader populations, showed that complete vaccination with the Pfizer/BioNTech vaccine induced the production of antibodies in 99.8% of subjects, whereas the AstraZeneca vaccine elicited the production of antibodies in 97.7% of subjects.
Preliminary analyses regarding response to mRNA vaccines revealed that the type of treatment that cancer patients undergo could influence their response to vaccination. Of the patients undergoing immunosuppressive therapies, such as chemotherapy and targeted therapies, 88% developed antibodies after complete vaccination, while this happened for 98% of patients receiving other types of treatment.
An analysis of the levels of antibodies shows that patients undergoing immunosuppressive therapies tend to have significantly lower levels compared to patients receiving other treatments.
The first results from this survey, which were presented in September at the European Society for Medical Oncology (ESMO) Congress, demonstrate the promising and innovative nature of this study.
The next step will be to monitor the duration of immune responses in these cancer patients and survivors, who will be tracked for at least a year.
INFO-VAC, an IGC programme, aims to track the effectiveness of vaccines in the real world and support future decisions, including which vaccines should be used in certain population groups. This is one of the initiatives of the Gulbenkian Foundation in response to the pandemic, which, in partnership with hospitals and municipalities, has been monitoring the effectiveness of the COVID-19 vaccines in different population groups, and has already collected a sample involving around 3.000 subjects.