Covid-19 travel restrictions to the US came into effect today.

The rules, announced last month, mean travellers will only be allowed to board US-bound flights if they have been fully vaccinated against the coronavirus.

Travellers will also be required to show proof of a clear pre-departure test taken inside three days of travel.

Exceptions will be made for children, people who have to visit the US for emergency or humanitarian reasons and people who cannot have the vaccine for medical reasons.

Others who may be allowed to enter the US without vaccination include people involved in Covid-19 vaccine clinical trials, travellers on non-tourist visas from countries with a low availability of vaccine, members of the Armed Forces and their families, airline crew, sailors and diplomats.