Two persons in north Bengal have died after they were administered the Covishield vaccine for Covid-19 this week, sources said.

Health department officials said preliminary reports suggested that the deaths were probably due to “natural cause of pre-existing cardiac conditions and coincidental to vaccination in nature.”

A 75-year-old woman of the Kharibari Block near Siliguri in Darjeeling district had received the shot on 8 March at around 3.30 pm. She returned home without any adverse events following immunisation (AEFI).

“However, the same day she was taken to the primary health centre at Batasi with bouts of diarrhoea and uneasiness and subsequently referred to the North Bengal Medical College and Hospital at 7.30 pm due to atrial fibrillation. She had been under treatment for atrial fibrillation for quite a long time. She died the following day,” senior officials of the health department said today.

Another 65-year-old person of Dhupguri in Jalpaiguri district had taken his first dose of Covishield on 8 March at the rural hospital at 10.30 am.

“He had returned home after preliminary observation without any AEFI. He, however, had vomiting at 4.30 pm the same day. The next morning, around 5 am, he developed sudden breathlessness and died at his residence within half an hour, without a chance for medical assistance. He was a known hypertensive for the past five-six years,” the official added.

Family members of the man have filed a complaint with the police in Dhupguri, demanding proper investigations.

The family members said in the complaint that the man did not have “much physical problems” and that they suspected he died of the vaccine.

“He had started complaining about uneasiness soon after taking the vaccine,” the complaint says.

The director of health services, Dr Ajoy Chakraborty, meanwhile, said investigations into the matter were on.

“According to preliminary reports, both of these deaths were probably due to natural cause of pre-existing cardiac conditions and coincidental to vaccination in nature. The primary report has revealed multiple cardiac problems, including cardiomegaly and cardiac muscle fibrosis, suggestive of old infarction. We are waiting for the final reports and it will be placed before the causality assessment committee,” Dr Chakraborty said.

According to the health department observation from those two cases, it appears that the vaccination was unlikely to be responsible for such sudden deaths in both the cases, as there had been preexisting cardiac conditions in both the cases which frequently cause sudden deaths in that age group.

“However, as in both of the cases, Covid vaccination was taken prior to the onset of symptoms, we need final confirmation and causality analysis by an experts’ team for both the cases based on postmortem findings and other evidences. The district and state AEFI committees are already investigating it and will ascertain and finalize the cause of death soon,” Dr Chakraborty said.

Scientists have revealed an overall vaccine efficacy for Covishield, the Astra Zeneca University of Oxford vaccine, produced in the country by the Serum Institute of India, of 70 percent.

Meanwhile, around 75054 persons took their first dose and 10465 received the second dose in 1151 sessions across the state today. The health department said, cumulatively 20.72 lakh people, including healthcare workers, frontline workers and elderly citizens, have been vaccinated in the state so far.

Also, one “minor” AEFI was reported today when an over 60-year-old resident of Falakata in Alipurduar district complained of pain at the point in his arm where the needle was injected soon after the vaccination with Covaxin. The person was sent home after initial observation, it is learnt.