Public health authorities have been persuading the general masses to get the COVID-19 booster shots once they have become available. But the guidance has mostly been for those who received the mRNA vaccines from Pfizer and Moderna, leaving recipients of Johnson & Johnson’s Janssen vaccine wondering if they also need the additional dose of the vaccine.

What The CDC Is Saying

The Centers for Disease Control and Prevention (CDC) updated its vaccination guidelines earlier this month to include a provision for the J&J vaccine booster shot. The agency indicated that Janssen recipients might also need to get a booster shot once they have become eligible for the extra dose.

The Janssen vaccine was developed to be a single-dose vaccine against the novel coronavirus. Unlike the vaccines from Moderna and Pfizer that utilize mRNA, Janssen makes use of attenuated adenovirus to help prime the immune system against COVID-19.

Just like the mRNA vaccines, the CDC said that Janssen recipients likely need a booster dose amid the ongoing global health crisis. However, the agency admitted that since the Janssen vaccine was not rolled out in the U.S. until 70 days after the mRNA vaccines, there is no official data to confirm the need for the J&J booster shots yet.

Can J&J Recipients Get mRNA Doses As Booster?

The CDC has strictly indicated that those who got the single-dose jabs from J&J should not get any of the mRNA vaccines as their booster. Janssen recipients will likely only be allowed to take a booster shot from J&J, mostly due to the difference in formulation.

J&J is currently in the process of testing its own booster shots. In a press release it posted on its website last week, the pharmaceutical company said that its booster doses significantly increased antibodies that target SAR-CoV-2 in its group of volunteers.

In the two studies it conducted, J&J administered the booster jabs six months after the volunteers had their first Janssen shot. The company said the additional shots increased the spike-binding antibodies “nine-fold higher than 28 days after the primary single-dose vaccination.”

Despite J&J’s update, Weill Cornell Medicine immunologist John Moore told ScienceMag that most unvaccinated Americans are still unlikely to take the first Janssen jabs, seeing that the “two-dose mRNA vaccines are so well established” at this point.

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