All India Institute of Medical Sciences chief Randeep Guleria on Saturday flagged the possibility of “misclassification” of Covid-19 related deaths, adding that state governments and hospitals should conduct death audits, reported NDTV.

“You may say this person died of a heart attack, but he may be Covid positive and the Covid itself may have caused the heart attack,” Guleria said, in an interview to the news channel. “So, you may have misclassified this as a non-Covid death, as a cardiac problem.”

Guleria’s comment came days after Bihar on June 10, added 3,951 backlog fatalities to its toll after the Patna High Court last month flagged irregularities and asked the state government to give an account of deaths during the second wave of the pandemic. A day later, Maharashtra also revised its toll, adding 2,213 deaths.

Several reports have also suggested that India’s toll could be much higher than the official figures, but the central government has so far refuted such claims. Guleria, however, said that it was crucial to know the actual number of deaths caused due to the virus.

“We have to know what are the causes of mortality and what can be done to bring down our death rate,” he said. “Unless we have clear data, we will not be able to develop a strategy to decrease our mortality.”

Responding to a question on breakthrough infections, Guleria said that while there were reports of such cases, the data was still very limited to say anything conclusively. Breakthrough infections refers to cases that are reported among those who are partially, or fully vaccinated against the virus.

“Breakthrough infection can happen...Our concern is you may get infected, but you should not get severe disease [after vaccination],” Guleria said. He added that the matter to look into was whether breakthrough infections are more common among mutant strains, like the Delta variant.

Last week, a research published in the medical journal Lancet had shown that the coronavirus vaccine developed by pharmaceutical company Pfizer is likely to produce 5.8 times lower levels of antibodies against the Delta variant, which was first detected in India.

The AIIMS chief also hinted at the prospect of another change in the dosage regimen of the Covishield vaccine, in order to deal with the risk of getting infected by the Delta variant after the first dose. Last month, the Centre had extended the gap between two doses of the Covishield vaccine to 12-16 weeks, from the earlier recommended interval of six to eight weeks. It was the third change in the dosage schedule since vaccination started in India.

Guleria said that the decision on keeping the interval at 12 weeks was made based on data available on the variants that were “circulating” in February-March.

“Now, there is some data which suggests that we may need to relook at it [gap between two doses], from the point of view of whether the duration may predispose people to getting breakthrough infection after the first shot with the Delta variant...This is being looked at by various expert groups.”

In an interview on Friday, United States’ top virologist Anthony Fauci had also recommended “staying on schedule” for intervals between two doses. He said that extending the duration may make people vulnerable to variants of the virus. However, Fauci’s comments were specific to mRNA technology-based vaccines developed by pharmaceutical companies Pfizer and Moderna. Both these vaccines are currently not in use in India. None of the vaccines approved in India so far are being administered in the United States.

In an earlier interview, after the Indian government had extended the gap , between two doses of the Covishield vaccine, Fauci had backed the move, referring to it as a “reasonable approach” to take when faced with a shortage of doses.

“It is very unlikely that it would have a negative effect on the efficacy of the vaccine,” he had said.