Any of the three COVID-19 vaccines the U.S. Food and Drug Administration has authorized for use in the United States is highly effective at preventing hospitalization and death. That was true months ago when the shots first came on the scene, and it’s true now. The feds have also authorized some Americans to receive a booster dose of Pfizer’s messenger-RNA—or MRNA—vaccine six months after initial doses, in order to bolster the effectiveness of that vaccine in the face of the Delta variant. Boosters could be coming soon for the vaccines from Moderna and Johnson & Johnson, too.
But there’s a possible mix of jabs that may—with careful study—ultimately prove even more effective: a dose of Johnson & Johnson’s conventional, adenovirus-based vaccine combined with a high-tech mRNA jab from Pfizer or Moderna. Multiple early studies in Europe focused on the AstraZeneca shot, which is similar to the J&J, have found that an adenovirus “prime,” or initial shot followed by an mRNA booster, might provoke the strongest and most enduring immune response yet to the coronavirus.