The US pharmaceutical company Moderna said Friday it will develop a booster shot against the new Omicron variant of the coronavirus. It is one of three strategies the company is working to address the new threat, including a higher dose of its existing vaccine, Moderna said. “The mutations in the Omicron variant are concerning and for several days, we have been moving as fast as possible to execute our strategy to address this variant,” said Moderna CEO Stephane Bancel. Meanwhile, President Joe Biden said other countries need to match US “generosity” and donate more Covid-19 vaccines, or the pandemic will not be stopped. “This pandemic will not end until we have global vaccinations,” he said in a statement from Nantucket, where he was spending the Thanksgiving holiday. Biden also called on countries to give up intellectual property protections to allow vaccines to be manufactured worldwide. The urgent appeal from the US president came as he imposed travel restrictions on eight southern African countries in response to the detection of the potentially dangerous new Omicron variant of Covid-19 in South Africa. “For the world community, the news about this new variant should make clearer than ever why this pandemic will not end until we have global vaccinations,” Biden said. “The United States has already donated more vaccines to other countries than every other country combined. It is time for other countries to match America’s speed and generosity.” He urged countries taking part in a ministerial level meeting of the World Trade Organization next week to lift intellectual property protections on their coronavirus vaccines, allowing manufacturing to expand rapidly. “This news today reiterates the importance of moving on this quickly,” he said.