President Trump is getting state-of-the-art care for his coronavirus infection, including the antiviral drug remdesivir and a monoclonal-antibody cocktail. Most Americans have limited access to these therapies. The antibody treatment hasn’t been approved by the Food and Drug Administration even for emergency use, so it’s available only to patients in clinical trials or on a case by case basis for compassionate use if approved by the FDA and drug manufacturer Regeneron. Remdesivir must be administered in a hospital, and patients often aren’t admitted until days after they develop severe symptoms.
But Mr. Trump is receiving one treatment you can buy without a prescription at your local drugstore: zinc. Last month, researchers from Spain reported that patients who died in hospitals in March and April on average had zinc blood levels of 43 micrograms per deciliter; survivors had 63. A level of 70 is considered normal. After adjusting for age, sex, illness severity and treatments, every unit increase of zinc in the blood was associated with a 7% lower likelihood of dying. That’s huge.
Zinc plays a critical role in regulating metabolism and the immune system. Over the years, many studies have found that people with low levels are more likely to develop pneumonia and recurring sepsis as well as suffer from conditions such as diabetes, kidney disease and chronic fatigue syndrome.
Severe zinc deficiency “depresses immune function,” the National Institutes of Health explains in a fact sheet for health professionals. “Even mild to moderate degrees of zinc deficiency can impair macrophage and neutrophil functions, natural killer cell activity, and complement activity. The body requires zinc to develop and activate T-lymphocytes.” Many of these issues “can be corrected by zinc supplementation.”
Usually an infectious agent will spur the body to produce more white blood cells, but severely ill Covid-19 patients tend to have low levels of lymphocytes. Antibody treatments like the one Mr. Trump is receiving are in part intended to compensate for a sluggish immune response in the earlier stages of the disease that later can result in an inflammatory “cytokine storm.”
Older people often have low zinc levels. One reason is their diets don’t include enough foods with zinc. Red meat is the best dietary source, but many older people avoid beef because they have a heart condition or are trying to prevent one. Whole grains, beans and nuts have zinc, but they include phytates that inhibit its absorption. The NIH notes that vegetarians may require at least 50% more zinc than nonvegetarians. Calcium supplements, which many postmenopausal women take to boost bone density, may also inhibit zinc absorption. Conditions like diabetes, kidney disease and ulcerative colitis can also reduce zinc absorption and increase its excretion. So can medications for hypertension.
A seminal clinical trial tracked nursing-home patients in Massachusetts from 1998 to 2001 who received a multivitamin supplement that included 50% of the recommended intake of zinc. Patients with normal levels of zinc at the start of the trial were 40% less likely to die from any cause. But the incidence of pneumonia was 50% lower during the trial in patients who had normal zinc levels at the study’s end. “Severe zinc deficiency can impair immunity and increase susceptibility to infectious diseases, a major cause of mortality in the elderly,” the study noted.
A recent article in the Journal of Medical Virology hypothesizes that zinc may also have an antiviral effect against Covid-19 because zinc may inhibit other RNA viruses, including coronaviruses. In a 2010 study, zinc coupled with an ionophore (a chemical that transports an ion across a cell membrane) was found to inhibit the replication of SARS.
Some Covid-19 studies have also shown promising results from pairing zinc with the antimalaria drug hydroxychloriquine (HCQ), another ionophore. A study of hospitalized patients in New York found that those treated with zinc on top of HCQ and the antibiotic azithromycin were about half as likely to die or be transferred to a hospice than those who didn’t receive zinc.
It is possible that the disparate results from studies evaluating HCQ as a Covid-19 treatment may be explained in part by zinc: People with inadequate zinc levels may simply not derive an antiviral benefit from the malaria drug. Those who have high-functioning immune systems may be able to defeat the virus without the help of drugs.
Healthy adults generally don’t suffer from zinc deficiencies so might not benefit from taking a supplement. Most people with adequate levels of zinc in their blood will excrete excess amounts or simply not absorb it in their guts. But people who are most vulnerable to the virus also tend to have zinc deficiencies, and this could help explain why some people infected with the virus get severely ill while others have mild or no symptoms. It certainly deserves more study. In any case, most Americans would do well to make sure they’re getting enough of the essential mineral.
Ms. Finley is a member of the Journal’s editorial board.
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