3. You only need one shot of the J&J vaccine.
This is a big advantage over other available vaccines. A vaccine delivered in a single dose will allow more people to get vaccinated.
Nevertheless, a J&J clinical trial is underway to see if a second shot could boost the vaccine’s effectiveness, so the one-shot strategy could change, says Dr. Zucker. But one dose is still highly effective.
4. It uses a different technology from the first two vaccines approved in the U.S.
Unlike the Pfizer and Moderna vaccines, which are mRNA vaccines, J&J’s is a viral vector vaccine. This means that the vaccine is delivered via an adenovirus, a type of virus that normally causes colds.
The adenovirus is engineered to include a snippet of SARS-CoV-2-DNA, which encodes the spike protein – the part of the coronavirus that latches onto cells. This snippet is then sent to your cells to produce mRNA, which tells your cells to make copies of the spike protein. Like the mRNA vaccines, this prompts an immune response.
“Your immune system recognizes the spike protein as abnormal and develops antibodies against it,” says Dr. Zucker. It takes about 28 days to get the J&J vaccine’s full protection.
5. The new vaccine can be stored at refrigerator temperatures for a long period.
“One of the big advantages of the J&J vaccine is that because it has an adenovirus vector and double-stranded DNA as opposed to mRNA, it’s much more stable,” says Dr. Zucker.
As a result, the vaccine is much less temperature-sensitive. It can be kept in a refrigerator for up to three months, which should make it easier to vaccinate people in rural or underserved areas.
The mRNA vaccines have stricter requirements regarding cold temperatures. That’s because mRNA is extremely fragile and disintegrates rapidly when it’s too warm.
6. You should get whichever vaccine you are offered.
The J&J vaccine is safe and very effective, and will likely keep you from becoming severely sick if you do contract COVID-19, says Dr. Zucker.
“We still have a problem in this country with high rates of infection,” he says. “The best approach is to take the vaccine that you can get the easiest and as quickly as possible. It will protect you.”