The best COVID vaccine is the one you can get quickly

Dear Dr. Roach: Could you explain the science behind the Johnson & Johnson COVID19 vaccine? I hear it differs from the Pfizer/Moderna vaccines as it does not contain the mRNA and is only a single dose. I also heard it compared to the flu vaccine. I am a flu vaccine recipient and if this is true, that may be the vaccine I am leaning toward. — D.J.

Dear D.J.: All the available vaccines are very effective at preventing serious illness from COVID-19. The “best” vaccine for everyone is the one they can get fastest. As vaccines become more and more available, most states have opened up vaccination to all adults.

There is an advantage in that the Johnson & Johnson vaccine is a single dose. It also has less stringent requirements for freezing/refrigeration, so it will likely have a major impact worldwide. But the J&J vaccine is much more similar to the Ebola vaccine than it is to the flu vaccine. It uses the mechanism of adenovirus (a cause of the common cold) to bring DNA into the muscle cells, which then tell the muscle cells to make the COVID-19 spike protein. The vaccine uses an adenovirus that is incapable of replication, so there is no risk of getting a cold from the vaccine.

The vaccine is about 65% effective at reducing moderate-to-severe COVID-19 disease, but it’s extremely effective (100% for those fully vaccinated) against mortality and COVID infections requiring hospitalization.

I continue to recommend that my patients get the first available approved vaccine — which I, and my family, have done. It’s particularly important as new variants develop to get as many people vaccinated as quickly as possible.