The COVID-19 pandemic has been a particularly stressful time for all patients with chronic diseases, and especially for cancer patients treated with chemotherapy. Beyond greater difficulty in receiving treatment during pandemic peaks, these patients have had to face a greater vulnerability to infection, due to their “immunosuppressive” treatment which not only targets cancer, but also impacts the immune cells that defend the body against infections.
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Patients “on” chemotherapy have a weaker immune response
after the 2 “usual” doses of the COVID-19 vaccine, this research confirms, however the injection of a 3rd dose makes it possible to restore the response to satisfactory levels. Doctors wanted to better understand the protection provided by COVID-19 vaccines to cancer patients, in particular with the relaxation of distancing measures and the emergence of more contagious variants.
The study: the follow-up of 53 Cancer Center patients under active immunosuppressive treatment against cancer, such as chemotherapy, made it possible to compare their immune response after the first and second doses of the Pfizer-BioNTech vaccine with that of 50 healthy adults. The analysis shows that:
- after 2 doses of the vaccine, most cancer patients showed a definite immune response to the vaccine, which means that they had indeed produced antibodies to SARS-CoV-2;
- this positive finding on the partially protective capacity of the vaccine for most people undergoing chemotherapy nevertheless reveals a much weaker immune response than in healthy adults;
- Finally, a few participants with cancer and treated with chemotherapy did not even develop a response to the COVID-19 vaccine. This suggests, write the authors,
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“Less protection of these patients against SARS-CoV-2, in particular against the delta variant”.
- 20 patients returned for a 3rd injection, which stimulated the immune response at – for the vast majority of participants, – levels similar to those of controls – not receiving chemotherapy.
These first results, from a nonetheless reduced sample of participants, suggest while awaiting broader research, that a 3rd dose would be welcome in this group of patients, in order to provide them with satisfactory protection against severe forms of COVID-19.
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