On Wednesday, the British government announced a shift in its coronavirus vaccine rollout that set it apart from the rest of the world. In a statement, the government said its priority would be to give the first vaccine dose to as many people it can, rather than focusing on giving people the required two doses in as short a time as possible, to give the maximum number of people some protection from the virus. However, according to Axios, Pfizer warned Thursday that there’s “no data” to show that a single dose of its vaccine will give people protection after 21 days. The drug maker said that two doses of its vaccine—separated by three weeks—is the only schedule proven to be 95 percent effective in its trials. The British government said that it will only guarantee people will receive their second dose within 12 weeks of their first, insisting that “completes the course and is important for longer term protection.”