DEAR DR. ROACH: I have a question about medications. I’m a soon to be 77 female. I have had Type 2 diabetes since about age 53. I am still on medication — metformin, glipizide and Actos. I previously was on glyburide and was doing well with an A1C around 7.1% or 7.2%. Then my doctor suddenly said glyburide was a dangerous drug and I must stop taking it. She substituted glipizide. This drug does not seem to work, as my A1C is now in the 7.8% range. Both of those drugs are in the same class and have the same warnings of heart failure, etc. I can’t get my doctor to relent and give me back the glyburide. She instead wants me to take an injectable, Victoza, and I’m not interested. What do you think? — S.H.

ANSWER: I think your doctor is concerned about glyburide causing low blood sugars. Glyburide not only lasts a long time, but it is metabolized by your body into other compounds that can also lower blood sugar. Especially in the elderly, those active compounds can cause a high risk of dangerously low blood sugars, and many experts do tend to avoid glyburide and use glipizide or glimepiride instead. If you have had any low blood glucose readings, I would agree with the change.

Liraglutide (Victoza) is called a GLP-1 antagonist. It is very helpful in people who need to lose weight, which includes many people with Type 2 diabetes, and in people with known cardiovascular disease. In my opinion, this class of drugs is proven to be safer than medicines like glyburide, and effective in people with those risk factors or who are at higher risk for low blood sugars.

Finally, A1C is a measurement of overall blood sugar levels, and I’m not sure additional medication is necessary for someone in their mid-70s with an A1C of 7.8%. A reasonable goal is 7.5%, and perhaps changes in diet or exercise may bring you there more safely than additional medication.

DEAR DR. ROACH: I am curious if there is any relationship between the Asian flu in 1968-1969 and having possible immunity to COVID-19? I had the flu while pregnant in 1968. I had been in very close contact to someone in September who came down with COVID the very next day. A serious case, but not hospitalized. I did quarantine, and then tested negative after two weeks. — J.M.

ANSWER: No, I don’t think that is at all likely. The influenza virus and COVID-19 are very different viruses, as different as a pineapple and a pinecone.

I don’t know why you didn’t get infected after having been in close contact with a known case. It’s not clear why some people seem to be more infectious, and perhaps some people are more susceptible. You may have had an asymptomatic case in the past. However, it is a mistake to consider yourself possibly immune to COVID-19, and a serious mistake to think this proves COVID-19 doesn’t exist, as a few people have written me. Even after getting the illness, or the vaccine, people need to continue to take precautions. No vaccine is perfect, and it is clear that even people who have had COVID-19 can get it again.

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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.