LONDON : British officials say they have signed a deal to buy 90 million doses of experimental coronavirus vaccines being developed by the pharmaceutical giant Pfizer and others.The British government said in a statement on Monday that it had secured access to a vaccine candidate being developed by a Pfizer and BioNTech, in addition to another experimental vaccine researched by Valneva.Britain had previously signed a deal with AstraZeneca to provide 100 million doses of the coronavirus vaccine being tested by Oxford University, which is expected to announce further results later Monday. “Millions of people could be vaccinated against coronavirus," the government statement said, citing the three different vaccines it has now invested.