The state health department is investigating into the deaths of four infants, including three who died between February 19 and 25, when the oral polio vaccine (OPV) immunisation drive was in progress. The fourth infant died in Mumbai on February 29 and had been given OPV drops and two more vaccines — DPT (diphtheria, pertussis (whooping cough) and tetanus) and hepatitis — a day earlier.

Speaking to TOI on Friday, assistant director (immunisation) and in–charge of the immunisation drive V M Kulkarni said, “ This year, we have reported deaths of three infants during the immunisation drive and one after the drive. We are investigating all the four deaths, which are, prima facie, coincidental.”

The national polio immunisation drive began in Maharashtra on February 19. On the same day, the first death was reported from Nandgaon village in Ratnagiri district. An eight–month–old baby girl, who had received OPV drops at an immunisation booth at 11.30 am, developed convulsions around 5.30 pm and died at a private hospital at 8 pm.

The second death took place at Sasara village (Sakoli taluka) in Bhandara district on February 21. An 18–monthold baby girl received OPV drops as well as measles, DPT, Japanese encephalitis and vitamin A vaccines at the state government’s sub–centre in Sakoli at 11 am. She died the next day at 3.10 pm.

Asked whether administering too many vaccines on the same day could have caused the death, Kulkarni said, “It is safe and effective to give more than one vaccine during a session. The only thing is that injections should be given at different injection spots, while using different syringes. In case of the baby, all vaccines were given at different spots. Again, the death is co–incidental.”

The third death was of a two–and–half–month–old baby girl from Panvel in Raigad district. She was administered OPV drops by the health department’s transit team at the Panvel railway station at 7.20 pm on February 24. The baby died at 3 pm the next day.

“Infant deaths after immunisation are usually coincidental. These deaths have some other co–factors linked to them. Still, the reasons for these deaths are investigated by the Adverse Effects Following Immunisation (AEFI) committees set up in all the 34 districts in the state. The babies’ death will also be taken up at the district committee concerned for audit and analysis,” Kulkarni said.

AEFI is a general term that covers various reasons, including bad vaccine quality due to breaks in the cold chain, contamination and complications due to pre–existing conditions of the child.

Chief minister Prithviraj Chavan had flagged off the polio immunisation drive in Maharashtra by administering the oral drops to two children at fort Shivneri, Junnar, in Pune district on February 19.

After the drive, the health department registered one more case of infant death. A two–month–old baby was administered DPT, OPV and hepatitis vaccines at the government’s Family Clinic No. 2 in Mumbai at 11 am on February 28. The baby died the next day at 6 pm.

Infant deaths have been reported in Maharashtra over the years, during the immunisation drive. The state health department’s report, released in May, last year, pegs such infant deaths in 2009–10 at 33, up from 26 and 15 in 2008–09 and 2007–08 respectively.

Calling vaccines safe, paediatricians say that while side–effects such as mild fever or redness at the spot where the shots have been administered are common, adverse reactions occur in one out of 10 to 20 million doses globally.