Moderna has designed an updated version of its Covid-19 vaccine to help it combat the South Africa coronavirus variant, the company announced Wednesday.
Initial doses have been shipped to the US National Institutes of Health for a clinical study.
The new vaccine, called mRNA-1273.351, will be evaluated as a booster shot for people who have already been vaccinated against coronavirus and as a primary vaccine for people who haven't had coronavirus and have yet to be vaccinated.
Moderna said it will also evaluate a "multivalent" booster shot that combines the new vaccine formulation with the current vaccine.
Additionally, the company said it has begun to test whether a third, lower dose of its current Covid-19 vaccine can increase immunity against coronavirus variants of concern, with some study participants already getting third doses.
On Monday, the US Food and Drug Administration issued new guidance to vaccine makers to address the emergence of coronavirus variants. The agency recommended that data from clinical immunogenicity studies be used to support any changes or updates to vaccines. Such studies would be smaller and could take less time than large-scale clinical trials.
"It's going to be on the order of a few hundred individuals in terms of size and we'd expect that that might take a few months," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said during a call with reporters on Monday.
Moderna said it plans to "evaluate immunogenicity and safety in participants" consistent with the recently updated guidance.
"We are moving quickly to test updates to the vaccines that address emerging variants of the virus in the clinic. Moderna is committed to making as many updates to our vaccine as necessary until the pandemic is under control. We hope to demonstrate that booster doses, if necessary, can be done at lower dose levels, which will allow us to provide many more doses to the global community in late 2021 and 2022 if necessary," Stephane Bancel, Moderna's CEO, said in a news release Wednesday.
Moderna did not say how long it expects the studies to take, or when the new vaccine would be available, if authorized.