Hypothesis or Truth: Role of Zinc, Re-used masks, Steam inhalation in Black fungus cases

Mucormycosis aka. Black fungus is caused by a fungus called mucormycetes. Mucormycetes are omnipresent, richly growing in warm, humid areas with low ventilation. It is an opportunistic infection which means the commonly occurring harmless fungus present ubiquitously in our environment can suddenly become harmful when provided with a conducive environment for survival and growth. Did you know that India was the Mucor capital of the world even before COVID, with more than 7000 cases reported. Now, as mucormycosis cases are rising alarmingly, every focus and effort are being put on strategies for prevention, better treatment. In this effort, theories start rolling out, which may or may not be accurate. In recent news, be it print or television, many mumbles are going on about the role of zinc, steam inhalation, and re-used masks in causing black fungus. I will put forward the hypothesis for each of these causing infection, and I will try to decode if it is the truth. You have to keep in mind that only research (which can take some time) can give correct answers, let our best minds and common sense prevail until then.

There are already a few established facts and widely agreed on causes for this mucormycosis epidemic. Let us have a recap of them before discussing the hypothesis. Mucormycosis affects patients having low immunity, and it proliferates in patients having blood (serum) rich in iron. In COVID 19 and diabetic patients, the immunity is lowered. COVID 19 also causes a rise in iron levels because it forms clots destroying blood cells. With steroids use, immunity gets hampered further, and steroids push the blood sugars further. High uncontrolled blood sugars produce an acidotic environment in which the iron levels rise. So, the combination of COVID 19, Diabetes, and high iron levels create a very conducive environment for the mucor to survive and thrive.

black fungus

During this COVID 19 pandemic, multivitamin supplementation and especially Zinc supplementation is highly recommended. Few pharma companies even came out hurriedly with new brands rich in vitamin c and zinc to cash in on demand. The hypothesis is that zinc, just like iron produces a suitable environment for mucor to grow. On searching the medical journals, I came accross this one article, where the researchers tried to remove the zinc from the blood of patients having mucormycosis through chelation. Although zinc depleted environment helped slow the growth of mucor, the chelation process was not well tolerated by patients. So the researchers felt that zinc depleting treatments should be made part of the treatment pipeline. Research article: NCBI


I have my doubts about the hypothesis that steam inhalation is causing a rise in mucor. The reasoning behind how steam inhalation is causing a surge in mucor is this.
1. Steam inhalation destroys the slimy mucous layer in the nose and sinuses, which acts as a shield against infections.
2. The Use of contaminated water in the vaporizers we use for steam inhalation can push microscopic mucor into our system.
3. The moist environment in the vaporizers, which are not allowed to dry and cleaned after every use, provides a suitable environment for mucor to grow. This mucor which grows, rushes into our nose the next time we use it.

The above reasoning sounds plausible, although I have my doubts about them. My advice is to do steam inhalation only when necessary. Make sure you clean the vaporizer dry after every use and allow it to dry in a place having good sunlight and cross ventilation. Do not inhale steam for more than 10 minutes for a maximum of twice a day.


The consensus from the medical community is that the masks are not to be re-used. The hypothesis is that there is moisture in the air we exhale into the mask, which gets trapped on the inner layer of the mask. This humid, warm environment is good for the mucor to grow. On re-using this mask the next day and beyond, we will start inhaling the mucor into our system. Again, it is plausible, and mask re-use is better to be avoided.

To summarise, zinc supplementation, overzealous, unnecessary, unclean steam inhalation, and re-usage of masks are better avoided. Detailed research and papers will start getting published in the coming months. Until then, every little bit of self prevention and care will go a long way in keeping you healthy.

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Medically reviewed by SinusDoctor,
Dr G V K Chaitanya Rao

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