Moderna ready to test version of Covid-19 vaccine aimed at worrisome variant

Moderna is pressing forward with a modified version of its Covid-19 vaccine meant to protect against an emerging strain of the virus, the company said Wednesday, planning to start a clinical trial as soon as regulators give the green light. Laboratory tests have suggested that Moderna’s authorized vaccine confers less protection against the variant, known as B.1.351, than it does against other strains. Pfizer has reported similar findings with its vaccine, and human trials conducted by Johnson & Johnson and Novavax suggest vaccines designed for the original strain of SARS-CoV-2 are less effective against B.1.351 as well. Moderna said it is seeking to test the novel vaccine on its own and as a combined shot with its current vaccine. It also plans to test whether giving a booster of the current vaccine on its own will give enhanced protection against new variants of the virus that causes Covid-19.