By Dr. Mallika Marshall

BOSTON (CBS) – Dr. Mallika Marshall is answering your coronavirus and 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.

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Patty writes, “I am 60-years-old and under 100 lbs while my 25-year-old neighbor is over 400 lbs. Why aren’t age and weight taken into consideration with dosing when so many other medications do that?”

Unlike some medications which are dosed based on weight or size, vaccines are different. With vaccines, you are introducing a tiny amount of material locally into the arm to stimulate the immune system. For most adults, that amount is the same regardless of size.

Flo on the Cape asks, “Is there any information regarding infertility and COVID-19? I’m particularly concerned if receiving the vaccine or getting COVID-19 would affect children and young adults becoming parents one day.”

There is no evidence that the vaccines cause infertility or cause miscarriages. This was a false claim made by anti-vaxxers in Europe and unfortunately, the rumor has spread far and wide. However, we do know that COVID-19 can cause pregnancy complications.

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Paula from Melrose writes, “I am vaccinated but still in a high-risk category. I walk twice a day. Should I be concerned about getting COVID-19 when maskless people walk or run past me on the sidewalk and are just one foot away?”

No, don’t worry about maskless people passing you by briefly outdoors. Being outdoors reduces transmission of the virus significantly, and now that you’re fully vaccinated, you should have good protection against COVID-19. Continue to exercise caution indoors, however.

Debbie says, “I just got my first shot of the vaccine yesterday. Is muscle tiredness or tingling a side effect of the vaccine?”

Yes, you can feel muscle aches, fatigue, and tingling after getting the COVID vaccine. That’s a sign that your immune system is working to produce antibodies against the spike protein of the coronavirus. Those symptoms should improve within a couple of days.

“D” writes, “I am an 81-year-old man considering the single shot J&J vaccine and wish to know if there have been any instances of serious adverse reactions, particularly blood clots, from that vaccine among men in my category.”

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The rare clotting disorder associated with the J&J vaccine has been seen almost exclusively in younger women, not in people over 60. I think the J&J vaccine is a wonderful option for a man of your age, but always check with your personal physician if you have any concerns.

Dr. Mallika Marshall