By Dr. Mallika Marshall

BOSTON (CBS) — Dr. Mallika Marshall is answering your coronavirus and coronavirus vaccine-related medical questions. If you have a question, email her or message her on Facebook or Twitter.

Dr. Mallika is offering her best advice, but as always, consult your personal doctor before making any decisions about your personal health.

Frank from Billerica writes, “I normally get a flu shot in the early fall. I am due for a Pfizer CCVID booster in November or December. How closely should I schedule my flu shot to the COVID shot?”

We generally recommend that you not get a COVID-19 vaccine within two weeks of getting any other vaccines. As long as you space the two vaccines out by two weeks, you should be fine. Good question!

Dana asks, “Should vaccinated people wear masks around others who are vaccinated?”

I think it depends on the circumstances. If you’re in close contact with someone who is vaccinated but has an underlying condition that makes them immunocompromised, you should both wear masks. And if you’re feeling under the weather, even if you don’t think it’s COVID, you should be wearing a mask.

Christina writes, “Why are the child infection numbers increasing?”

I think for two main reasons. First of all, we’re dealing with a variant (Delta) that is much more contagious than previous variants. And people are socializing and fraternizing more frequently than they were months ago. Children, in particular, are going to camps, playdates, sleepovers, amusement parks, sporting events, etc., where they can catch the virus, and many are catching it when their parents or siblings bring it home.

Nina asks, “A family member got COVID recently. He was fully vaccinated back in May. He has been in isolation for 10 days and without symptoms for three days. Should he test negative before he returns to work?”

If he has completed his 10 days of isolation, is feeling better and is fever-free, he should be able to return to work. He does not need to get retested beforehand. The test can remain positive for weeks after infection, but that does not mean he is still contagious.

Dr. Mallika Marshall