By Dr. Mallika Marshall

BOSTON (CBS) – Dr. Mallika Marshall is answering your coronavirus vaccine-related medical questions. If you have a question for Dr. Mallika, 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.

Should people who have had COVID-19 still get vaccinated?

Yes. We’re not sure if people who get infected with the coronavirus can get infected again. They probably develop some degree of immunity but how strong that immunity is or for how long it lasts is still not understood. Therefore, people who have been infected in the past should eventually be immunized but not until they have fully recovered from their illness. According to the CDC, they may be able to wait up to 90 days from initial infection.

You have received a number of questions from viewers asking if people with weakened immune systems can get the Pfizer vaccine. What does the CDC say about this?

The Pfizer vaccine was not specifically studied in people who are immunocompromised, however, they are at risk for severe COVID-19. So the CDC says people with HIV or patients on immunosuppressive drugs can receive the vaccine in consultation with their doctors. However, there is some concern that the vaccines may be less effective in people who cannot mount a robust immune response.

What about pregnant women?

Again, the Pfizer vaccine has not yet been specifically tested on pregnant women but they are at higher risk of severe illness and preterm birth. Based on what is known about the mRNA technology used in the Pfizer and Moderna vaccines, it’s unlikely it would pose a risk to pregnant women or their offspring. So pregnant women and even women who are breastfeeding should strongly consider getting vaccinated, again, in consultation with their doctors.

There has been a report of a severe allergic reaction to the vaccine in a healthcare worker in Alaska. Should people with a history of allergies get the Pfizer vaccine?

If you have a known allergy to an ingredient in the Pfizer vaccine, you should hold off at this time. However, people who have had a severe allergic reaction to something else in the past can still get vaccinated but should be observed for 30 minutes afterward. People with non-life-threatening allergies to foods, pollen, or latex, for example, can proceed without special precaution.

Dr. Mallika Marshall