Covid-19 Variant Vaccines in Works at Johnson & Johnson

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

J & J’s original Covid-19 vaccine was approved by US regulators in late February. At a late stage of study, the shot was 66% effective in protecting people in a large international study from moderate to severe Covid-19 disease.

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

Other companies including Moderna Inc.

are also taking steps to develop and test modified vaccines that may better target variants.

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

Laboratory tests and clinical studies have generally shown that the original Covid-19 vaccines retain much of their protection against a highly transmissible variant first identified in the UK.

Their potency appears to be diminished against the strain first identified in South Africa, although J & J’s vaccine was solidly effective in a clinical trial to prevent serious and critical cases of Covid-19 there.

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

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

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

J&J executives have previously said they were working on a possible vaccine to target the variant first identified in South Africa, but it was not yet clear which variants it would target in further development.

A variant-targeted J&J vaccine could be particularly useful in countries that rely on the easier storage and handling requirements for J&J vaccine technology. The shot can be kept in the refrigerator longer than the messenger RNA vaccines from Moderna and Pfizer Inc.,

which could be useful in lower-income countries with more limited cold chain distribution infrastructure.

Write to Peter Loftus at [email protected]