The chief of the Council of Scientific and Industrial Research, India’s largest chain of industrial laboratories, and two other scientists have criticised a study published in The Lancet medical journal, on the lack of benefits of anti-malarial drug hydroxychloroquine to treat Covid-19, The Hindu reported on Saturday.

In a separate development, a group of over 100 researchers signed a letter pointing out inconsistencies, calling on the authors and The Lancet to reveal more details about their analysis, The New York Times reported.

The study, published on May 22, looked at more than 96,000 people hospitalised with Covid-19, the respiratory disease caused by the novel coronavirus. It said that those treated with hydroxychloroquine or the related chloroquine had a higher risk of death and heart rhythm problems than patients who were not given the medicines. Two days later, the World Health Organization “temporarily suspended” trials of hydroxychloroquine, citing the study.

Director-General of CSIR Shekhar Mande, Anurag Agrawal, physician and director of Institute of Genomics and Integrative Biology and director of Chennai Mathematical Institute Rajeeva Karandikar wrote to WHO chief scientist Soumya Swaminathan on Friday. They said the decision to suspend trials of the drug was a “knee-jerk” reaction and opposed the move.

“The observational data is sloppy, and the statistics underlying them is faulty,” Mande told the newspaper. “There is no doubt that it will not stand the test of time. You can’t compare apples with oranges.”

Mande said WHO’s decision does not stop any country from conducting trials, adding that the Lancet study would create fear in the minds of people. The letter said that the drug appeared less effective because the data suggested that those chosen to take HCQ were much more sick than the rest of the group. “This is not unexpected here and highlights the well-known problem of statistical comparisons of unbalanced unrandomised groups in observational studies,” it added.

The group of over 100 experts, meanwhile, pointed out 14 major shortcomings in the paper, including the fact that the computer code used to analyse the data wasn’t made public, and that no information was included on the medical centers that contributed data. The letter also said that the rates of deaths reported from Africa seemed “unlikely”, the daily doses purportedly received by some American patients appeared higher than recommended, and that the level of chloroquine use in some continents was “implausible”.

Earlier this week, Indian Council of Medical Research, the country’s nodal body for coronavirus testing, said that hydroxychloroquine may still be used against the coronavirus as it has not found any major side-effects. India has been using the drug extensively, and has also exported it to many other countries including the United States.

On May 22, the Ministry of Health and Family Welfare revised its advisory on the use of hydroxychloroquine as a prophylactic against the coronavirus. The ministry’s decision came after the National Task Force, constituted by the ICMR, reviewed and recommended the use of the drug for coronavirus patients.

United States President Donald Trump had also said he has been taking hydroxychloroquine as a preventative medicine despite a lack of scientific evidence.

Also read: India is relying on flimsy evidence to expand use of HCQ despite concerns about dangers