London, Sep 21 (IANS): Vaccination against Covid-19 is effective in patients with cancer, whose immune systems get weakened by various anti-cancer medicines, according to studies presented at the annual congress of the European Society for Medical Oncology.

The findings revealed that individuals with cancer have an appropriate, protective immune response to vaccination without experiencing any more side-effects than the general population. Indirect evidence also suggests that a third "booster" shot could further increase the level of protection among this patient population.

One of the studies, named VOICE, showed that patients with cancer who took Covid jab were protected regardless of the current oncology treatment.

The study enrolled 791 patients from multiple hospitals in the Netherlands in four distinct study groups comprising individuals without cancer, patients with cancer treated with immunotherapy, patients treated with chemotherapy and finally patients treated with a chemo-immunotherapy combination, to measure their responses to Moderna's two-dose mRNA-1273 vaccine.

At 28 days after administration of the second dose, adequate levels of antibodies to the virus in the blood were found in 84 per cent of patients with cancer receiving chemotherapy, 89 per cent of patients receiving chemo-immunotherapy in combination and 93 per cent of patients on immunotherapy alone.

These results compare favourably with the antibody responses seen in almost all (99.6 per cent) of the group of individuals without cancer, according to Dr Antonio Passaro, lung cancer expert at the European Institute of Oncology in Milan, Italy, not involved in the study.

"The high rates of efficacy of the vaccine observed across the trial population, regardless of the type of anticancer treatment, constitute a strong and reassuring message for patients and their doctors," he added.

Similar results were found in another study conducted on the effects of tozinameran (Pfizer-BioNTech) among 232 patients with cancer and 261 control subjects in Israel. While less than a third of individuals with cancer (29 per cent) developed antibodies after receiving the first dose, compared to 84 per cent in the control group, this proportion increased to 86 per cent following administration of the second dose.

Both the above studies also stressed on the need for taking the second shot of Covid vax for patients with cancer to develop enough protective antibodies against the virus.

A study published in the New England Journal of Medicine showed that a booster shot on people 60 years or older, after five months of completing their vaccination cycle, reduced the incidence of Covid-19 and severe illness.

"These findings lend additional support to the principle of offering the complete cycle, possibly including a third booster dose, to patients with cancer to improve their protection, because it suggests their immune system will respond to the extra stimulation," said Dr Luis Castelo-Branco, Medical Oncologist, ESMO Scientific and Medical Division, who was not part of the studies.