DEAR DR. ROACH: How does one manage natural immunity to COVID-19 if one has an autoimmune disease? Does that person take vitamin D3, zinc, etc.? — J.K.S.

ANSWER: “Natural immunity” refers to the protection that is conferred after a natural infection, as opposed to vaccination. Studies have shown that protection from infection following a case of COVID-19 is about 80% to 85% for six months after infection. However, immunity to a different variant (such as the delta variant widely circulating at the time of this writing) from the one a person was infected with may be substantially less. It is unknown how long the immunity lasts after infection, but it is likely to wane with time.

Dr. Keith Roach

There is no good evidence that vitamin D supplementation reduces the likelihood of getting COVID-19 or getting a milder case or that it increases immunity. Similarly, zinc and vitamin C are undergoing further study, but there are not good data showing effectiveness as treatment or preventive for these supplements.

Autoimmune disease such as autoimmune thyroid disease does not increase the risk of a bad outcome with COVID-19. This is in contrast to immune deficiencies such as HIV or many of the primary immune deficiencies, which do confer risk of a worse outcome with COVID-19 and are likely to decrease the protection following vaccination or a natural infection that a person survives.

However, medications to treat autoimmune diseases often lead to greater risk — and less immunity to COVID-19. That’s because these medications cause a degree of immunosuppression. Some medicines are much more likely to do so than others. Unfortunately, supplements have not been proven of value.

Because there are many people undergoing treatment for autoimmune diseases, or who have immune deficiencies (including those caused by treatment of cancer and other diseases), vaccination and natural immunity are unable to protect everyone in a population. When there is ongoing community transmission, which as I write this is increasing in all 50 states, additional protective measures, such as social distancing and mask wearing, are necessary.

DEAR DR. ROACH: My niece died at age 65. She was initially diagnosed with Parkinsonism but in the last year of her life she was diagnosed with multiple system atrophy. She had been a very healthy person, eating well and exercising regularly. Prior to her diagnosis, I had not heard of MSA. We do not know of any other family members with this. Are the risk factors for this condition known? — P.W.

ANSWER: I am sorry to hear about your niece.

Multiple system atrophy is a group of rare, fatal, degenerative neurological diseases. Common to these diseases are some features that resemble Parkinson’s disease, including a tremor, slowed movements and instability. In some cases of MSA, the Parkinsonian symptoms predominate. However, in MSA, there are profound abnormalities in the autonomic nervous system, the part of the nervous system that regulates blood pressure, urinary function and breathing. The blood pressure problems can be very disabling, causing large drops in blood pressure when standing. Urinary incontinence occurs in most people with MSA, and common breathing disorders include sleep-related disorders such as sleep apnea and REM sleep behavior disorder, in which people move violently during dreams.

Although there are rare familial cases of MSA, there is not a clear genetic cause, nor have there been convincing reports of environmental exposures to cause this fortunately rare group of conditions.

A neurologist with special expertise is the ideal physician leader to treat this problem, but many other experts are useful, including physical and occupational therapy, and a speech and swallowing expert.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.