A 90% effective coronavirus vaccine in the preliminary stages of development has sparked hope among health professionals.

The vaccine was developed by Pfizer and BioNTech, who described it as a “great day for science and humanity”, according to BBC News.

No safety concerns have been raised for the vaccine, which has been tested on 43,500 people across six countries.

Two doses per person are needed, with protection achieved seven days after the second dose. Manufacturers aim to release 50 million doses by the end of this year, and 1.3 billion doses by the end of 2021.

However, at this early stage there are still potential challenges and complications ahead.

It is not clear if the vaccine stops the spread of the virus or only prevents the development of symptoms.

The vaccine’s effectiveness for high-risk and elderly people also remains to be seen, and it could be years before we know if long-term immunity is possible.