New York, Jun 29 (IANS): Covid-19 vaccines are highly effective in preventing severe infections or death, but patients with multiple myeloma -- a type of blood cancer --- are immunocompromised and often on immunosuppressive therapy.

The mRNA-based Pfizer and Moderna Covid vaccines evoked a lower and delayed response in them compared to healthy people, finds a study, asserting need for monitoring or continued precautions in patients with cancers.

Researchers from the Icahn School of Medicine at Mount Sinai found that almost 16 per cent of patients with multiple myeloma developed no detectable antibodies after both vaccine doses. These findings may be relevant to other cancer patients undergoing treatment and to immunocompromised patients. The study will be published in Cancer Cell.

"This study underscores the need for routine blood tests on multiple myeloma patients after vaccination to understand their risk and potential need to continue wearing masks and socially distance until the pandemic wanes," said Samir Parekh, Professor of Medicine (Hematology and Medical Oncology), and Oncological Sciences, at Mount Sinai.

"This also calls for clinical trials to study the use of prophylactic therapies, like monoclonal antibodies, to mitigate Covid-19 risk or to use different vaccines or booster vaccinations in these patients," he added.

Repeat antibody measurements from before patients' first vaccine dose until 60 days after the second vaccination showed delayed and suboptimal responses, particularly in patients with multiple myeloma who had not contracted Covid-19 before their vaccinations.

Patients on active cancer treatment had significantly lower antibody levels after two vaccine doses than multiple myeloma patients who were not on treatment at the time of vaccination, the researchers said.

The team analysed the antibody levels of 320 multiple myeloma patients, 260 of whom received two doses of Covid-19 vaccinations, and found that 15.8 per cent had undetectable antibodies.

The multiple myeloma patients who had had Covid-19 before vaccination showed immune responses that were 10 times higher than those who had not.