Pfizer said November 20 it is asking US regulators to allow emergency use of its COVID-19 vaccine, starting the clock on a process that could bring limited first shots as early as next month and eventually an end to the pandemic -- but not until after a long, hard winter.

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The action comes days after Pfizer Inc and its German partner BioNTech announced that its vaccine appears 95 percent effective at preventing mild to severe COVID-19 disease in a large, ongoing study. The companies said that protection plus a good safety record means the vaccine should qualify for emergency use authorization, something the Food and Drug Administration can grant before the final testing is fully complete. In addition to November 20 FDA submission, they have already started rolling applications in Europe and the UK and intend to submit similar information soon.

With the coronavirus surging around the US and the world, the pressure is on for regulators to make a speedy decision. Help is on the way, Dr Anthony Fauci, the top US infectious disease expert said on the eve of Pfizer's announcement, adding that it's too early to abandon masks and other protective measures. We need to actually double down on the public health measures as we're waiting for that help to come. November 20 filing sets off a chain of events as the FDA and its independent advisers debate if the shots are ready. If so, still another government group will have to decide how the initial limited supplies are rationed out to anxiously awaiting Americans.

How much vaccine is available and when is a moving target, but initial supplies will be scarce and rationed. About 25 million doses of the Pfizer vaccine may become available in December, 30 million in January and 35 million more in February and March, according to information presented to the National Academy of Medicine this week. Recipients will need two doses, three weeks apart.