DEAR DR. ROACH: I am a 72-year-old woman who is blessed with good health. In my adolescent years, I occasionally got strep throat, but a respected doctor of internal medicine (later head of a medical school) cautioned my mother against ever having my tonsils taken out. The general advice of the day was to have them removed, but he said that the tonsils are the first line of defense against more serious infections — that they serve to filter out bad microbes that invade the body and a mild sore throat can be proof that the tonsils are doing their job.

I wonder, when doctors or researchers are putting together their questionnaires to attempt to determine why one person has certain symptoms of a disease but not others, or why certain people are more vulnerable to an infectious disease when others aren’t, is the question ever asked if patients still have their tonsils? It strikes me as a simple question that could possibly lead to a deeper analysis of the body’s defense mechanisms. — S.J.W.

ANSWER: Long-term followup of children who have had their tonsils removed shows approximately double the risk of developing respiratory infections in the subsequent 10-30 years. Removing the adenoids (typically done at the same time) increased the risk of developing chronic obstructive lung disease.

As you note, far fewer of today’s children have their tonsils out compared with the almost routine tonsillectomy of years ago. I agree with you that more research is called for. However, I will note that during an exam, lack of tonsils and adenoids is usually quite apparent, and enlarged tonsils certainly are.

DEAR DR. ROACH: I entered a market with my cloth face mask on, and went down an empty aisle. I smelled perfume, quite strongly. I am wondering how protective face masks are from COVID-19 when I could easily smell the perfume from a person who had been in that aisle previously or was in a nearby aisle. — D.H.

ANSWER: Human sense of smell is very acute, and perfumes are designed to be noticed. The chemicals that form a perfume are generally much smaller than a virus, and go right through the holes in a mask. Much of the risk from COVID-19 appears to be from virus carried on large droplets. These are effectively filtered out by the masks.

What is not completely clear is how much risk there is from very small droplets or aerosols, which an ordinary cotton mask cannot filter. However, the data are clear that mask wearing is very effective. Hospital workers use N95 masks or even more advanced protection to prevent inhaling smaller particles, especially during procedures that are likely to create a lot of infectious respiratory particles.

Staying further away from people and wearing a mask remain effective ways of minimizing risk. If the person with COVID-19 — whether or not they realize it — is wearing a mask as well, the risk is even lower. That’s why it’s so important that everyone comply with mask-wearing, since many people who are infectious with SARS-CoV-2 do not know it.

* * *

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.