Moderna's chief medical officer said the company could release an updated vaccine by early 2022.
News of the vaccine modification comes as the new Omicron variant begins to spread globally.
Pfizer and Johnson & Johnson are also testing vaccine effectiveness at fighting the Omicron variant.
Moderna said it might release an updated COVID-19 vaccine to combat the new Omicron variant by early 2022.
"We should know about the ability of the current vaccine to provide protection in the next couple of weeks," Chief Medical Officer Paul Burton said Sunday on the BBC's "Andrew Marr Show."
"If we have to make a brand new vaccine, I think that's going to be early 2022 before that's really going to be available in large quantities," Burton continued.
News of an updated vaccine comes as scientists and health officials warn the Omicron variant, first detected in South Africa, could spread easily across the world. It has already spread to several other countries, including Israel and Belgium, prompting a spate of travel restrictions across Europe, Asia, and North America, Insider's Aria Bendix reported. A health official said on Saturday that two cases of the variant have been detected in the UK. And Dr. Anthony Fauci, the topmost coronavirus virologist in the US, said it's likely to have already touched down here.
The variant itself has multiple mutations that might make it easier for it to evade antibodies that developed in the body after receiving a COVID-19 vaccine. The mutations might also cause the variant to spread easily - even among vaccinated people.
The World Health Organization has labeled Omicron a "variant of concern," a distinction given to the most threatening coronavirus variants. Delta, the variant that surged all throughout the summer in the US, was the last one to receive the label.
It's not clear yet whether existing COVID-19 vaccines will protect against the variant. But vaccine manufacturers have already begun considering their options.
Moderna said in a Friday news release that the company is testing its current vaccine against the Omicron variant.
"Since early 2021, Moderna has advanced a comprehensive strategy to anticipate new variants of concern," the company said. "The company has repeatedly demonstrated the ability to advance new candidates to clinical testing in 60 to 90 days."
Pfizer said it will be able to manufacture and distribute an updated version of its COVID-19 vaccine within 100 days if Omicron is found to be resistant to its current vaccine. The company said it expects to know within two weeks whether the variant is resistant to its current vaccine, a company spokesperson told Reuters.
"Pfizer and BioNTech have taken actions months ago to be able to adapt the mRNA vaccine within six weeks and ship initial batches within 100 days in the event of an escape variant," the company said in a statement.
Johnson & Johnson has begun testing the effectiveness of its vaccine against the Omicron variant.