Dr. Roach: Shedding after vaccine? No. Asymptomatic and contagious? Yes

Keith Roach
To Your Health

Dear Dr. Roach: In a recent column, you wrote that there is no risk to family from shedding after receiving the COVID-19 vaccine. You failed to mention that according to the Centers for Disease Control and Prevention, the grandparents could catch COVID and spread it even after being fully vaccinated. Also, according to the CDC, they might be contagious and have a viral load, even before they start showing any symptoms. Isn’t the only way to ensure they are not contagious to be tested?


Dr. Keith Roach

Dear D.I.: The topic of that column was shedding after a vaccine, and it is true there is no risk of shedding COVID-19 from the vaccination. However, you are correct that it is possible for a vaccinated person to have active, asymptomatic infection.

New data from the age of the delta variant shows that asymptomatic, vaccinated people may indeed by infectious. For this reason, wearing a mask remains important, especially around people at high risk for complications for COVID-19. That includes vaccinated individuals.

It’s very important to note that the risk of asymptomatic infection spreading from a vaccinated person is much lower than from an unvaccinated person, simply because someone who is vaccinated is a lot less likely to get COVID-19.

Dear Dr. Roach: I’m an 83-year-old woman. Two years ago, I was diagnosed with diverticulitis. It comes and goes. My doctor recommended I see a surgeon, who recommended a sigmoidoscopy. I don’t see what the benefit is. I had two CT scans that showed diverticulitis. The surgeon said he would not do surgery on me.

Do you think I should have the sigmoidoscopy? Is there any risk to this procedure? The doctor said I would be sedated, and I am very reluctant to have it done.


Dear P.S.: All procedures have risks. A sigmoidoscopy generally has fewer risks than a full colonoscopy, but there is still a risk of damage to the colon, and even moderate sedation, by itself, has risks. The likelihood of benefit must be weighed against the risk of harms.

In your case, I think I can guess why the surgeon wants you to get the sigmoidoscopy. The diagnosis really isn’t in doubt – the CT scans you had are definitive. My best guess is that the surgeon wants to be sure there isn’t something else there, especially cancer. The risk of being diagnosed with colon cancer after diverticulitis is substantially higher than would be expected, especially in a person with recurrent symptoms, as you have had. Unless you had an examination of your colon within the past year, such as a colonoscopy, the guidelines recommend an evaluation. The authorities recommend a full colonoscopy, but I suspect your surgeon wants to look most specifically at the area of the colon with the diverticula, which is usually the sigmoid colon. As I noted, a sigmoidoscopy has fewer risks than a full colonoscopy.

This is my guess, but I recommend that since you are reluctant to have the procedure done, ask the surgeon why you need it. The surgeon shouldn’t get upset by you asking. It’s our job to explain why we recommend what we do, and the reasons why we recommend it over the alternatives.

Readers may email questions to ToYourGoodHealth@med.cornell.edu.