Moderna said Wednesday it has shipped to the National Institutes of Health doses of a new Covid-19 vaccine designed to provide better protection against the highly contagious coronavirus variant spreading in South Africa.
The vaccine – which Moderna is calling mRNA-1273.351 – is ready to be tested in an early stage clinical trial to determine if it can be used as a booster shot against the South African strain, also known as B.1.351, the company said. Moderna has found its current two-dose regimen generates a weaker immune response against the strain from South Africa, though the company said antibodies in patients remain above levels that are expected to be protective against the virus.
“Moderna is committed to making as many updates to our vaccine as necessary until the pandemic is under control,” the company’s CEO, Stephane Bancel, said in a press release. “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.”
The company said Wednesday that it plans to evaluate three approaches to increasing immunity. The first approach would use variant-specific booster shots, such as mRNA-1273.351, but at a lower dose than the original vaccine. The second one would combine the original vaccine with a variant-specific vaccine into a single shot at 50 micrograms or lower, Moderna said. The third would test a third shot of the original vaccine at a lower dosage.