Why does India have so many cases of post-Covid mucormycosis?

Careful prescription.
Careful prescription.
Image: Reuters/Adnan Abidi
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As the cases of “black fungus” infections continue to rise in India, doctors and scientists worry if there is more to it than just the use of steroids.

Mucormycosis, colloquially known as black fungus, is a serious fungal infection that was seen in far smaller numbers in India before Covid-19, too. But it is now affecting post-Covid patients in large numbers. As of May 22, the government has reported 8,848 cases of this fungal disease, which can lead to serious complications and has a high rate of mortality.

Thus far, this surge has been attributed to the improper use of steroids to treat Covid-19 patients, coupled with poorly managed diabetes. But steroids in themselves are not the villains.

“Systemic (oral and intravenous) corticosteroids have been proven to reduce mortality in Covid-19,” Lancelot Pinto, consultant pulmonologist at Mumbai’s Hinduja Hospital, told Quartz. “The largest trial, Recovery, which proved this beyond a reasonable doubt among individuals who had low oxygen levels, used them in a dose of 6 milligrams Dexa per day for up to 10 days.”

Not only in Covid-19, but steroids are also widely used in orthopaedic and pulmonary diseases. In India, the problem lies not in the drug but in how it is prescribed. “Most of us who work in India will agree that prescribing practices more often than not tend towards higher doses for longer periods of time, which is a clear risk factor for invasive fungal infections,” Pinto said. Added to this, there is no strict prescription check in India, and most drugs—even those that need a prescription—can be easily bought over-the-counter.

“In addition, India has an epidemic of type 2 diabetes, and a significant proportion of patients with diabetes are diagnosed late in the illness,” which, according to Pinto, could be contributing to this surge in cases.

A cocktail of drugs in India

Other infections after a viral disease are common because viruses suppress immunity. For instance, post-viral bacterial infections are quite common. But such infections run the risk of becoming hardy and resistant to drugs.

This is particularly worsened by the common practice of prescribing a cocktail of drugs to patients with even mild Covid in India. “We do not know whether the widespread use of cocktails of drugs, most of which have no proven role, but have been used assuming that they would do no harm, could actually contribute to cases of mucormycosis,” Pinto added.

For instance, a zinc supplement is commonly prescribed to Covid-19 patients at high doses, supposedly to increase immunity and aid the body in fighting the virus. Pinto and others like Rajeev Jayadevan, consultant gastroenterologist at Kochi’s Sunrise Group of Hospitals, have been particularly concerned about the possible role of zinc in aiding the fungal infection to take root.

Another likely cause could be the improper use of oxygen cylinders—with unclean masks or without purified water in the apparatus—which became a norm in most cities grappling with a hospital bed shortage. But Pinto suggests that’s not entirely likely.

“I would be surprised if the home use of oxygen alone could be a cause, as we have many respiratory conditions (some of them treated with corticosteroids under observation) in which patients are on long-term home oxygen, and invasive mucor infection hasn’t been as common in such patients,” he said.

Pinto also believes that only a proper audit of current mucormycosis cases can offer scientific answers and end speculation. “Presently, every hypothesis is being aired, and this leads to fear and paranoia. Healthcare systems across the world have been overwhelmed, but that hasn’t led to a surge in mucormycosis cases,” he said.

Till such an audit is done, what can patients and doctors do differently?

How to prevent mucormycosis

Pinto offers some guidance on how patients and doctors can prevent mucormycosis:

  • Check your blood sugars when you get diagnosed with Covid-19. The infection itself can cause a rise in blood sugars, and this can be independent of whether you have pre-existing diabetes.
  • Avoid any therapy that does not have a proven role in treating Covid-19, no matter how innocuous it may seem.
  • Doctors need to avoid three pitfalls when it comes to using oral or intravenous corticosteroids: their use too early (if oxygen levels have not dropped), or their use routinely in higher doses than recommended (6 mg Dexa a day, or 32 mg methylprednisolone a day, or 40 mg prednisolone a day), or for longer periods than recommended (up to 10 days).
  • When given for short periods, corticosteroids do not need to be tapered and can be abruptly stopped safely.
  • Extra caution needs to be exercised among patients with other co-existing immunosuppressive conditions such as chronic liver disease, kidney disease, or autoimmune diseases and malignancies.