The largest COVID-19 vaccination campaign has kicked off in the United States. Medical workers are among the first to be vaccinated against COVID-19, AP reported.

Valuable vaccine vials manufactured by Pfizer Inc. and its German partner BioNTech have begun arriving at hospitals across the country.

This is the light at the end of the tunnel. But it's a long tunnel, New York Governor Andrew Cuomo said while overseeing vaccinations.

Several other countries have also approved the vaccine, including the UK, which began vaccinations last week.