Add the German port of Bremen to the list of those vaccinating seafarers as the global roll-out gains momentum.

Regardless of where in the world they are from, those aboard ships calling at the major car and container port will be able to receive the one-shot Johnson & Johnson Covid-19 vaccine, officials said on Monday.

"Sailors are affected particularly severely by the pandemic as they cannot disembark in ports, as crew changes are made difficult or impossible by international travel restrictions, and because medical care is often not guaranteed," said state science and ports minister Claudia Schilling.