Muslims planning to travel from Britain to Saudi Arabia on pilgrimage will need to be vaccinated against seasonal flu before they can enter the country. New travel rules from the Saudi government mean that Britons cannot apply for a visa without a vaccine certificate that is at least two weeks old. If a vaccine for swine flu is available before November, when the annual Hajj pilgrimage takes place, British Muslims will be required to have that as well to prevent further outbreaks of H1N1. About two million Muslims from around the world travel to the holiest place in Islam, Mecca every year.