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HCQ shows no use as Covid protective drug for health workers, finds Indian study

The study by the Journal of the Association of Physicians of India also found the positivity rate to be slightly higher among subjects who took HCQ.

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New Delhi: Hydroxychloroquine (HCQ) as a prophylactic has no use, concluded a study published in the Journal of The Association of Physicians of India (JAPI).

Researchers, in fact, found that the positivity rate was slightly more in people using HCQ as a prophylaxis, or preventive, than among those who were not using it.

The findings come at a time a trial to examine the preventive effects of HCQ on possible novel coronavirus (SARS-CoV-2) cases is set to restart in the United Kingdom.

Other international studies have arrived at similar conclusions, while some in India concluded that the drug, normally used for the treatment of malaria and autoimmune disorders, can prevent the coronavirus infection.

India has recommended prophylactic use of HCQ among healthcare workers and all other frontline workers. It has also recommended the drug’s use as a post-exposure prophylactic for family members of patients of Covid-19, particularly for immediate caregivers.

Also read: Not sure if HCQ works but adverse effects don’t seem to be a problem, say Indian doctors

What the study found

Although there were more than 4,000 trial subjects, complete data was available for only 3,667 of them, from which the study draws its conclusions. Of these subjects, 1,113 were tested for the virus along with 539 others who developed flu-like symptoms. Twenty subjects (1.8 per cent) eventually tested positive.

From the group tested, 755 used HCQ as a prophylactic. Of them 14 subjects (1.9 per cent) tested positive for the virus, higher than the 1.7 per cent positivity in those that did not take the drug.

Health care workers (HCW) from high-risk zones reported more symptoms than those from low-risk zones but there was no difference in positivity rates. The authors wrote: “This is the first study on healthcare workers from India to the best of our knowledge. Our findings suggest that posting in a high risk zone with adequate PPE does not pose higher risk to the HCWs. Moreover, HCQ as a prophylactic has no use.”

There were 52.1 per cent males and 47.9 per cent females in the sample population with the median age being 18-40 years.

The study by doctors at Max Healthcare analysed data from 3,667 healthcare workers (doctors, nurses, paramedics etc.,) from the five Max hospitals in the Delhi-NCR region, BLK Superspeciality Hospital and Nanavati Hospital in Mumbai. The data was collected between 23 March and 30 April. The first advisory by the Ministry of Health on prophylactic use of HCQ was issued on 23 March.

“Many HCWs were taking HCQ/chloroquine/azithromycin prophylaxis on an individual basis. In our study, HCQ prophylaxis played no role in prevention of this infection. Multiple systematic reviews also concluded that there is no pertinent data to support use of HCQ outside that of research, and there is lack of clinical data to actually support its efficacy, adverse effects like prolongation of QTc and tends to instill a false sense of protection,” the researchers wrote.

Prolongation of QTc refers to an abnormal ECG which is one of the known adverse effects of HCQ use.

Calling for further large-scale studies on healthcare workers, the researchers said that given the higher positivity rates among symptomatic patients, it makes sense to conserve resources to focus testing on symptomatic people and do extensive contact tracing.

Also read: Trump’s HCQ push still keeps US door open for India’s banned Ipca Labs

International experience

The findings about HCQ not being an effective prophylactic agent are not new though they are the first ones on Indian healthcare workers to be published.

Earlier this month, in a study in the New England Journal of Medicine, researchers from the University of Minnesota, McGill University and several other institutions reported: “After high-risk or moderate-risk exposure to Covid-19, hydroxychloroquine did not prevent illness compatible with Covid-19 or confirmed infection when used as postexposure prophylaxis within 4 days after exposure.”

It also reported higher side effects with HCQ (over 40 per cent) than with placebo (16 per cent).

Another important difference from the Max study in this case was that it was a double blind placebo-controlled trial. This means that in this trial, people who got HCQ or placebo did not know what they were getting. That ruled out the “false sense of protection” that the Max researchers mention. Both the trial and control groups reported similar rates of positivity.

Also read: HCQ farce has tragic consequences as precious time studying treatments has been lost

India’s recommendation

India has been steadfast in its recommendation of the prophylactic use of HCQ since March. On 22 May, the advice was extended to all frontline workers and not just health workers. In the order, HCQ use was mandated for all asymptomatic frontline workers, such as surveillance workers deployed in containment zones and paramilitary/police personnel involved in Covid-19 related activities, apart from the other two groups for which it was recommended in March.

Three studies were taken into account by the Indian Council of Medical Research’s Covid-19 task force to make these recommendations, the central government said. In a retrospective study, ICMR found a “significant dose-response relationship between the number of prophylactic doses taken and frequency of occurrence of SARSCoV-2 infection in symptomatic healthcare workers who were tested for SARS-CoV-2 infection”.

Another investigation from three central government hospitals in New Delhi found that healthcare workers on HCQ prophylaxis were less likely to develop SARS-CoV-2 infection. The third was an observational prospective study of 334 healthcare workers at AIIMS, out of which 248 took HCQ prophylaxis (median 6 weeks of follow up) in New Delhi. That also showed that those taking HCQ prophylaxis had lower incidence of SARS-CoV-2 infection.

In May, the Telangana government released an interim report on a study on healthcare workers who had been taking HCQ as a prophylactic. The study conducted at the Gandhi Medical College in Secunderabad reported that 394 of the 694 people who came in contact with a positive patient but remained symptom-free. Of them, 71 per cent were tested randomly for the virus and all tested negative.

Also read: ‘Star’ cardiologist Mehra & data doctor Desai — story of Indian experts behind HCQ scandal

Side effects

The side effects that both the JAPI and the NEJM study speak about have been documented in other studies too.

India’s health ministry advisory says: “The data on assessment of HCQ prophylaxis among 1,323 HCWs indicated mild adverse effects such as nausea (8.9%), abdominal pain (7.3%), vomiting (1.5%), hypoglycemia (1.7%) and cardio-vascular effects (1.9%). However, as per the data from the Pharmacovigilance program of India, there have been 214 reported instances of adverse drug reactions associated with prophylactic HCQ use. Of these, 7 were serious individual case safety reports with prolongation of QT interval on ECG in 3 cases.”

This is why the drug is not recommended for use in children, pregnant and lactating women, people with existing heart and other conditions. There has to be constant monitoring and an ECG has to be done at least once in the course of its use.

Also read: Divided by a virus — why the pandemic makes it look like nobody is in control in India


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  1. There is a misunderstanding of how chlorquinone works – both for Covid-19 and for malaria. Chlorquinone won’t prevent infection by the virus. So looking at the rate of infection is choosing the wrong metric to look at.

    However, it (chlorquinone) will reduce the severity of the symptoms, and the death rate. India has one of the highest uses of chlorquinone as a prophylactic, and despite a continuing exponential rise in infections, has a death rate far lower than other countries. This could be explained by the higher use of chlorquinone as a prophylactic.

  2. None of these studies including the studies in NEJM are actually testing for COVID or robustly ensuring that hydroxychloroquine has been taken. NEJM study did not test 98%, the second NEJM study 42%, and this study by expensive hospitals seems to have tested only one third.

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