A COVID-19 vaccine developed by German biotech firm BioNTech and US pharmaceutical giant Pfizer has shown potential and was found to be well tolerated in early-stage human trials, the companies say.
The drug is one of 17 being tested on humans in a frantic global race to find a vaccine the world is counting on to end a pandemic that has infected 10.5 million people and killed more than half a million so far.
The potential treatment is the fourth early-stage COVID-19 drug to show promise in human testing, along with projects involving Moderna, CanSino Biologics and Inovio Pharmaceuticals.
BioNTech's shares were up about 8.0 per cent, after rising as much as 19 per cent to reach their highest in more than three months.
Pfizer stock also gained, rising 4.4 per cent to $US34.13.
In turn, shares in some rival vaccine developers such as Moderna and Novavax Inc dropped.
BioNTech said testing of two dosages of its BNT162b1 drug on 24 healthy volunteers showed that after 28 days they had developed higher levels of COVID-19 antibodies than typically seen in infected people.
It said the higher of the two doses - both administered via two injections within three weeks of one another - was followed by a short fever in three out of four participants after the second shot.
A third dosage, tested at a higher concentration in a separate group, was not repeated after the first shot because of injection pain.
"These first trial results show that the vaccine yields immune activity and causes a strong immune response," said BioNTech's co-founder and Chief Executive Officer Ugur Sahin.
He said larger trials were being prepared to show whether this translates into protection against a real infection.
"While more work needs to be done, we believe the benefits appear to outweigh the risks so far, especially when considering the disease the vaccine is trying to prevent," Mizuho Securities analyst Divan Vamil said in a note.
Bernstein analysts said their initial impression was that the data was "solid" but noted they don't expect the initial generation of vaccines to be silver bullets in terms of conferring nearly complete protection.
Australian Associated Press