BCG vaccine does not protect against Covid, says new study

Mumbai: The Covid pandemic seems to be heading towards an endemic phase, but a chapter started almost two years back to check the efficacy of the BCG vaccine against the Covid-causing SARS-CoV-2 is still wide open.

A paper published recently said the BCG vaccine, originally given to neonates to protect them against tuberculosis, doesn’t protect against the Covid-causing SARS-CoV-2 virus, while a study done in the city on Covid patients in April-May 2020 showed the TB vaccine could be used as therapy.

Scientists led by Dr Usha Padmanabhan from the Haffkine Institute, Parel, found Covid-19 patients admitted in some Mumbai/Pune hospitals who were given the BCG shot after their diagnosis had reduced hypoxia (reduced oxygen) and pneumonia, “lesser ICU admissions and deaths and increase in antibodies.” Dr Padmanabhan said the 60-patient study had shown those who were given the vaccine improved faster. “In May 2020, there was no treatment or vaccine on the horizon. Now, we have dedicated vaccines against Covid,” she said.

The latest study on BCG-Covid, published in ‘Cell Reports’ journal, looked at the vaccine’s usefulness against viral infections, including Covid-19. Conducted by the McGill University in Montreal, Canada, it found BCG vaccination significantly reduced morbidity and mortality against influenza A virus, but it failed to provide protection against SARS-CoV-2.

Dr Madhu Pai, professor (epidemiology) from University of McGill, said, “Only randomised animal and human trials can establish if BCG can protect. Data so far do not support the hypothesis.” His argument is: India has given the BCG vaccine at birth for decades. “If it had protected, we would not have had such devastating waves and so many deaths,” he said. Dr Shashank Joshi, member of state task force, said, “BCG may have adjuvant role in boosting a patient’s immunology, especially T and beta cells. Many other vaccines could have a similar role to play,” he said. But this general hypothesis needs to be backed by solid evidence based on randomised control trial.