BANGALORE - Indians may have been thrilled when American scientists suggested that populations who received BCG vaccines might be less vulnerable to Covid-19. Most infants born in India since 1985 have received these anti-tuberculosis shots.

As the Covid pandemic spread, however, these immunisation practices came to a halt.

National Health Mission data shows that in March, at least 100,000 children nationwide did not receive their BCG vaccination, and another 200,000 did not get the pentavalent vaccine that protects against five life-threatening diseases.

In the first 10 days of April, only 52 per cent of the designated vaccine storage centres nationwide operated, while fewer than 20 per cent ran in Andhra Pradesh, Karnataka and Assam.

India provides free immunisation against 12 vaccine-preventable diseases, including polio, tuberculosis, and meningitis. But since the country turned its attention to battling the coronavirus, and imposed a lockdown in mid-March to prevent transmission, children have stopped getting their vaccines.

An estimated 71,000 children are born in India every day. Without life-saving vaccinations for weeks, millions of infants are now vulnerable to diseases, including tuberculosis, mumps, measles, pneumonia, hepatitis B and tetanus.

In March, states like Uttar Pradesh, Bihar, Rajasthan, Karnataka and Kerala officially suspended outreach efforts by accredited social health activists, auxiliary nurses and midwives who coax rural families to vaccinate their children.

"All field workers were diverted to contact-tracing and door-to-door surveillance for Covid," said Ms Geeta Berva, who works in a health centre in rural Rajasthan. Immunisation in the state fell to about 29 per cent in the first 10 days of April.

The southern state of Kerala has stopped all immunisation since the lockdown, presuming children would be at less risk of contracting vaccine-preventable diseases like measles, mumps and polio when at home. In neighbouring Karnataka, a health official said the suspension was a precautionary measure to prevent Covid transmission.

The central state of Madhya Pradesh stopped immunisation without official orders as dozens of its own top health officials tested positive for the coronavirus.

Mr T.S. Singh Deo, health minister of Chhattisgarh, said his state did not issue orders to stop immunisation. "But the focus had flagged with the Covid onslaught. All the staff were busy with Covid work," he said.

"States offered immunisation at health centres but most people won't travel 10-15 km to get their child vaccinated. And under lockdown, even those who wanted to go didn't have travel facilities," said Jaipur-based Ms Chhaya Pachauli, a member of the People's Health Movement that flagged these concerns with the Rajasthan government.

Seeing disruptions in immunisations in several countries, the World Health Organisation warned last month about a resurgence of diseases that are preventable with vaccines. Soon after, the Indian ministry of health advised states to restart these services.

Some states have now gradually restarted inoculation.

Most immunisations used to be done at local schools, but now health workers in Chhattisgarh will visit the children and mothers at their home, said Mr Deo.

Mr Rohit Kumar Singh, additional chief secretary of health in Rajasthan, said the western state "will ensure that all children who missed their sessions get immunised now. There is a lot of focus on getting non-Covid health activities back on track".

He added that the state usually did 10,000 vaccine sessions a day before Covid started, and did about 8,000 sessions a day last week.

On May 21, the federal ministry of health issued an advisory ordering immunisation to continue in all non-containment zones, and birth doses to be given irrespective of zone.

"If states act now, we can still catch up on the two-month backlog. But the government should also give booster doses for children who have missed out on their essential vaccines," said Ms Pachauli.