Do I need a booster if I got the Johnson & Johnson vaccine?

Probably at some point, but health officials still are collecting the data needed to decide.

With boosters being planned in the U.S. as early as the fall for those who got the two-shot Pfizer and Moderna vaccines, recipients of the single-dose J&J jab might be wondering just how well their protection is holding up.

All the vaccines used in the U.S. — including the J&J vaccine — still are doing their job of preventing hospitalizations and deaths from COVID-19.

“I don’t think there’s any signal that the J&J vaccine is failing at its primary task,” said Dr. Amesh Adalja, an infectious disease specialist at the Johns Hopkins Bloomberg School of Public Health.

Despite continued protection against severe disease, U.S. officials are planning to offer Pfizer and Moderna boosters eight months after the second shot based on evidence that effectiveness against infection wanes over time. Adding to the decision, the vaccines don’t appear quite as strong against the highly contagious delta variant as they were against earlier versions of the virus.

U.S. Surgeon General Vivek Murthy said boosters “will likely be needed” for the J&J vaccine. Authorities expect more data to decide in the coming weeks.

That’s in part because the J&J rollout didn’t start until March, several months after Pfizer and Moderna vaccinations began. The J&J shot is made differently. And there’s more data about how the Pfizer and Moderna vaccines fare against delta because they’re more widely used in countries where the variant struck before its U.S. surge.

There is some real-world data showing J&J’s shot holds up against the delta variant. A huge study of health workers in South Africa showed the vaccine remains highly effective against hospitalizations and death from the variant. And the vast majority of so-called “breakthrough” infections in vaccinated people were mild.

J&J has also presented lab data on virus-fighting antibodies that indicates its vaccine protects against the delta variant for eight months and counting. Another small lab study has raised questions about whether a two-dose approach would work better, an option J&J is studying.

A separate issue is whether people with severely weakened immune systems should get extra shots as part of their original vaccinations, since they don’t respond as well to any vaccines. The government now recommends a third shot of the Pfizer or Moderna vaccines for organ transplant recipients and others in this group. But it’s still collecting data before making a similar recommendation for another dose of the J&J vaccine.