Drugmaker Pfizer said on Monday that its coronavirus vaccine had succeeded in the final stage of clinical trials, and is more than 90 percent effective in preventing COVID-19.

As Business Insider's Andrew Dunn reported, developing a vaccine for a brand-new virus in less than a year is something that has never been achieved.

But announcing a vaccine and having large numbers of people receive it are two different things.

Here is Business Insider's summary of what needs to happen next, and how long it might take:

  • Pfizer wants more data on the vaccine's safety before moving ahead. It says the data will be available the week of November 16.
  • The US Food and Drug Administration then needs to decide whether to give emergency approval. It is unclear how long this might take, but the agency has said it wants to move fast. (Another caveat: The authorization at first may only be for the most at-risk groups like the elderly and healthcare workers.)
  • Pfizer said some doses can be delivered this year - but only 50 million for the whole world.
  • Each dose takes two shots, so the 50 million doses are only good for 25 million people. Patients also have to wait three weeks between their first and second shots.
  • 2021 is when the bulk of doses will arrive - up to 1.3 billion. This is when people who aren't considered high risk might start to get it.
  • The vaccine has to be moved at ultra-cold temperatures - as low as minus 94 degrees Fahrenheit or minus 70 degrees Celsius - which could make it hard to get to some places quickly.
  • Other logistical issues - like a shortage of glass vials - could stand in the way of a smooth vaccine rollout.

A number of countries have already put in orders for millions of doses of the vaccine, in the hopes that it will work to protect their populations, including the US, the UK, Canada, Japan, and countries across the European Union.

Other companies around the world are also working on producing coronavirus vaccines, with results expected soon.

This article was originally published by Business Insider.