Covid-19 Variant Vaccines in Works at J&J

“We have to be prepared,” Mr. Gorsky said Thursday. “We should prepare for the worst and hope for the best.”

J&J’s original Covid-19 vaccine was authorized by U.S. regulators in late February. In a late-stage trial, the shot was 66% effective at protecting people in a large international study from moderate to severe Covid-19 disease.

But its efficacy was lower in the South Africa portion of the trial, where a variant has spread that has shown resistance to vaccines that were designed to work primarily against an earlier version of the virus that circulated widely last year.

Other companies including Moderna Inc. also are taking steps to develop and test modified vaccines that may better target variants.

Researchers are exploring whether some variant-targeted vaccines should be given as a booster shot or as part of a “multivalent” vaccine that also targets other strains.

Lab tests and clinical trials have generally shown that the original Covid-19 vaccines retain much of their protection against a highly transmissible variant first identified in the U.K.

Their potency appears reduced against the strain first identified in South Africa, though J&J’s vaccine was solidly effective in a clinical trial at preventing severe and critical cases of Covid-19 there.

Some virus variants “are more concerning because they result in fundamental mechanistic changes that can have an impact, for example, on the rate of transmission or potentially even morbidity or mortality,” Mr. Gorsky said during an online discussion hosted by the Economic Club of New York.

He said the need for booster shots or modified vaccines will depend on how variants evolve in the coming months, but the company is preparing now. “We’re working on several next generations of vaccines,” he said.

New Brunswick, N.J.-based J&J also is conducting a study of whether two doses of its vaccine are more effective than the currently authorized regimen of a single dose. Results are expected later this year.

J&J executives have previously said they were working on a potential vaccine to target the variant first identified in South Africa, but that it wasn’t yet clear which variants it would focus on in further development.

A J&J vaccine targeting a variant could be particularly useful in countries that are counting on the easier storage and handling requirements for J&J’s vaccine technology. The shot can be kept stable in a refrigerator for a longer period than the messenger RNA vaccines from Moderna and Pfizer Inc., which could be helpful in lower-income countries with more limited cold-chain distribution infrastructure.

Write to Peter Loftus at [email protected]