(Reuters) -BioNTech, Moderna (NASDAQ:) and Johnson & Johnson (NYSE:) are working on vaccines that specifically target Omicron in case their existing shots are not effective against the new coronavirus variant, the companies said on Monday.

This variant has caused a global reaction. Countries concerned that it might spread quickly even among vaccinated people have imposed travel restrictions and other restrictions.

BioNTech SE (NASDAQ 🙂 announced that it has begun work to develop a vaccine for Omicron in collaboration with a partner Pfizer (NYSE:).

Meanwhile, Moderna Inc said it could take months to begin shipping such a vaccine, Chief Executive Officer Stéphane Bancel told CNBC.

Bancel stated that the current effectiveness of COVID-19 vaccinations against this variant is not yet known. He added that more information should come in the next two weeks.

Johnson & Johnson is also evaluating the effectiveness of its COVID-19 vaccine against Omicron, while also pursuing a vaccine specific to the variant.

“We have begun work to design and develop a new vaccine against Omicron and will rapidly progress it into clinical studies if needed,” said Mathai Mammen, global head of research for J&J’s pharmaceuticals unit.

Omicron, according to a top South African expert in infectious diseases, is more easily transmissible to humans than other variants. This includes people who have immunity to vaccinations or had prior infections.