To Your Good Health: Are two vaccines better than one when it comes to COVID-19?

DEAR DR. ROACH: My wife and I are grateful to have recently received our second Moderna vaccine. When the crush relents, would you see any difficulty in adding the J&J vaccine at my own expense? It seems that the different vaccines vary in how they protect against different strains, and I’d like to double up (or even more) if there are no major risks. — F.M.

ANSWER: The Moderna vaccine appears to be nearly 95% effective in preventing COVID-19, and probably even more effective in preventing severe COVID-19 resulting in hospitalization or death. I do not know whether giving a second course of a different vaccine will lead to an even higher degree of protection, nor whether it might lead to worse side effects.

What is most critical right now is to get the vaccine administered to as many people as possible to stop ongoing transmission. That means prioritizing those who haven’t had it, particularly those at higher risk. Soon, however, there may be enough vaccine to consider studying whether additional vaccination will be helpful. I can’t think of a historical case where multiple types of vaccines given together led to improved outcomes, but we do seem to be living through a historic event.

DEAR DR. ROACH: My husband thought his second shingles shot was in January, but it was in February, and he took his COVID-19 vaccine only one week apart from the shingles vaccine. He didn’t have any reaction to either COVID shot. Were those two kinds of vaccines taken too close, canceling out the effectiveness? I am worried he won’t have the protection from both vaccines to get immunity. — K.L.

ANSWER: There is no data on administering other vaccines along with the COVID-19 vaccine, so it is recommended to leave a buffer of two weeks between vaccines. However, if a vaccine really needs to be given near the same time, it can. The Centers for Disease Control and Prevention stated: “If COVID-19 vaccines are administered within 14 days of another vaccine, doses do not need to be repeated for either vaccine.”

DEAR DR. ROACH: I was receiving my second injection of the Moderna COVID vaccine when I felt wetness on my arm and hand. It appears some or all of the vaccine leaked. I felt the needle enter my arm and then the wetness. The nurse stated the vaccine entered my arm.  He wiped down my arm. I did NOT have a sore arm nor any other side effects.  After the first injection I had a sore arm and fatigue. So, am I fully vaccinated?  Should I receive another injection? — A.B.

ANSWER: It is not uncommon for a small amount of the vaccine to leak out of the arm after injection. Recommendations from experts state that if at least half of the vaccine went in, the dose does not need to be repeated. Presumably the nurse noted only a small amount of leak, but I can’t say for sure what happened or how much went in. A small proportion of the vaccine can look like a whole lot on the outside of your arm. If you are really worried that you didn’t get enough of the vaccine, I would discuss with the person in charge of the administration site the possibility of getting another dose.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to or send mail to 628 Virginia Dr., Orlando, FL 32803.

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