More promising data on a COVID-19 vaccine from Pfizer and its German biotech partner, BioNTech boosted their shares Monday.

The companies said that data showed their experimental vaccine was safe and that it induced an immune response.

The trial in Germany tested 60 healthy volunteers. It found that those given two doses of the vaccine produced virus-neutralizing antibodies. That follows a corresponding early-stage trial they conducted in the U.S. earlier this month.

Companies around the world are racing to develop and test 150 possible vaccines. Twenty three candidates are in human clinical trials. But experts say it’ll take up to 18 months to develop a safe and effective vaccine.