BioNtech's U.S. shares gained 12%, while Pfizer's stock rose 3.6% in early trading.
The companies said the data also demonstrated an induction of a high level of T-cell responses against the novel coronavirus.
Experts have cautioned a safe and effective vaccine will take 12-18 months to develop.
The results were disclosed from a trial in Germany testing 60 healthy volunteers, and come after the companies earlier this month reported data from a corresponding early-stage trial in the United States.
The trial showed that volunteers given two doses of the vaccine produced virus-neutralizing antibodies, similar to the U.S. trial.
The data is available on an online preprint server at medrxiv and is undergoing scientific peer-review for potential publication, the companies said.