A US judge has thrown out a lawsuit by more than 100 employees of one of Texas's largest hospitals, who sued after being required to get vaccinated against Covid-19, AFP reports.

They argued Houston Methodist Hospital's demand was illegal so long as the available shots have received only emergency use authorisation from US health authorities — though that authorisation has cleared the way for millions of Americans to be vaccinated.

The hospital set a June 7 deadline for workers to prove they had received at least one dose or face termination.

“Receiving a Covid-19 vaccination is not an illegal act, and it carries no criminal penalties,” federal court Judge Lynn Hughes wrote.