Moderna announces vaccine upgrades to protect against emerging variants

Moderna is tweaking its coronavirus vaccine to make it more effective against emerging variants of the virus, the company announced Monday.

The upgrades will be designed to better protect against the different strains and could be used as a booster shot. The announcement comes as scientists around the world scramble to get ahead of a constantly mutating virus that has already killed more than 2 million people worldwide.

“As we seek to defeat the Covid-19 virus, which has created a worldwide pandemic, we believe it is imperative to be proactive as the virus evolves,” Moderna CEO Stéphane Bancel said in a statement.

Moderna said its existing vaccine is effective against a more contagious variant that is thought to have emerged in the United Kingdom. But the vaccine was less protective against a strain that was first reported in South Africa. An early study found that with the South African variant, the level of antibodies produced from the vaccine diminished sixfold, according to the company.

Despite the observed drop, Moderna said neutralizing antibodies — which can bind to viruses and block them from getting into cells — remained above protective levels for both. Still, it is “unknowable what will happen in six months, in 12 months,” Bancel said Monday on CNBC.

Bancel said the vaccine upgrades are being developed “out of an abundance of caution,” but added that the reduced antibody levels seen with the South African variant may suggest that protection against this and future variants could wane.

"Immunity may go down over time," he said.

Moderna’s study, conducted together with the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases, examined blood samples from immunized monkeys and eight people who received the company’s regular two-dose vaccine regimen. The preliminary results have yet to be published or peer reviewed.

Bancel said it will be crucial to conduct ongoing research that aims to boost immunity to emerging strains.

“We cannot be behind — we cannot fall behind this virus,” he said.