By Dr. Mallika Marshall

BOSTON (CBS) — Dr. Mallika Marshall is answering your 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.

Can two family members who are positive isolate together? And if someone who is fully vaccinated and boosted with no symptoms is positive, how long do they isolate? – Evelyn

Yes. If two family members test positive at the same time, they should be able to isolate together. Anyone who tests positive, regardless of whether they’re vaccinated or not, should isolate for a full 10 days.

Friends are having their annual Christmas party with 25 plus people. I am having knee replacement surgery that following Monday. I have been fully vaccinated and boosted. Is it safe for me to attend this party? – Karen

This is such a difficult question to answer because you’re going to have to weigh the risks and benefits. I would hate for you to get exposed right before you are scheduled to have surgery. But if you feel comfortable that everyone at the party is vaccinated and boosted and has a very low risk of being infected, it’s something you might decide is worth the risk.

My daughter had a bad reaction after her second Moderna shot with fever, chills, and body aches. She’s nervous about getting the booster even though it’s half the dose. Should she get Pfizer instead? – Mimi

I’m sorry she had these side effects. It’s hard to predict whether she would have the same side effects with the lower dose Moderna booster. She certainly can consider getting a Pfizer booster instead. As a precaution, tell her to take a day or two off after whichever booster she gets and to rest, hydrate, and take over-the-counter pain or fever reducers if she has similar side effects.

I received the J&J vaccine and was scheduled to get my booster this week, but got COVID last week. Should I still get a booster shot? That would then be three different substances in my body with the potential of more variants and more boosters down the road. – Brittany

I think you can wait a little while before getting a booster, but probably should get it within three months of your infection. It’s unclear whether prior infection with Delta (most likely the strain you contracted) will provide any protection from the Omicron variant (which will soon be the dominant strain in the U.S.), but booster shots should provide some additional protection.

Dr. Mallika Marshall