Germany's BioNTech, Pfizer's partner in COVID-19 vaccines, said the two companies would start tests on humans of next-generation shots that protect against a wide variety of coronaviruses in the second half of the year.

Their experimental work on shots that go beyond the current approach include T-cell enhancing shots, designed to primarily protect against severe disease if the virus becomes more dangerous, and pan-coronavirus shots that protect against the broader family of viruses and its mutations.

The two partners, makers of the Western world's most widely used COVID-19 shot, are currently discussing with regulators enhanced versions of their established shot to better protect against the Omicron variant and its sublineages.

(Reporting by Ludwig Burger and Patricia Weiss)