Are two vaccines better than one for COVID-19?

Dear Dr. Roach: My wife and I are grateful to have received our second Moderna vaccine. Would you see difficulty in adding the J&J vaccine at my expense? It seems the vaccines vary in how they protect against different strains, and I’d like to double up if there are no major risks. — F.M.

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

What is most critical is to get the vaccine administered to as many people as possible. That means prioritizing those who haven’t had it. Soon, there may be enough to consider studying whether additional vaccination will be helpful.

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 one week apart from the shingles. He didn’t have any reaction. Were those two kinds of vaccines taken too close, canceling out the effectiveness? I am worried he won’t have protection to get immunity. — K.L.

Dear K.L.: 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. However, if a vaccine 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.”