Vaccines need extensive evaluation

Dear Dr. Roach: I read recently that a coronavirus vaccine is scheduled for release in late October or early November. This seems awfully early. I am 77 years old so my age puts me in the higher risk category for contracting COVID-19. Would you recommend I get this vaccine as soon as it becomes available?

P.L. Answer: For me to recommend a vaccine, it must have undergone extensive evaluation, showing that its benefit far outweighs its risk. This requires a large number of volunteers and a significant follow-up period to identify any potential adverse effects. I have consistently advised taking the currently recommended vaccines because of that thorough evaluation prior to approval and because of continued monitoring after release.

I am unaware of any vaccine that has the kind of record that would allow me to recommend it outside a clinical trial. While it is possible that such evidence will become available in the future, as of this writing I cannot recommend a coronavirus vaccine.

Dear Dr. Roach: I would like to know why my vitamin D level is low and I

have sarcoidosis of the skin from tattoos.

Y.M. Answer: Sarcoidosis is a difficult disease to explain, since nobody really knows what causes it. The characteristic cell of sarcoid is the multinucleate giant cell, causing a granuloma, which is a collection of immune cells.

Tattoos can be affected by sarcoid, and occasionally are the first place that sarcoid starts. Red tattoo dye appears to be the most common trigger. Some people with tattoo sarcoid will then go on to develop lung or other body system sarcoid.

The granuloma of sarcoid is capable of making the active form of vitamin D, calcitriol. This can raise blood calcium levels, which shuts off production of vitamin D. The usual vitamin D level in the blood will then appear to be low when in fact the person has high levels of active vitamin D. Giving high doses of extra vitamin D can make the high calcium level worse. Routine levels of vitamin D are not harmful.