(Adds minister quotes)LONDON, April 7 (Reuters) - Britain begins rolling out Moderna's COVID-19 vaccine on Wednesday in Wales and expects to be using it in the rest of the United Kingdom in the coming days in a boost to the country's health system after supplies of shots started to slow.Moderna will become the third vaccine to be used in Britain after the Oxford-AstraZeneca and Pfizer (NYSE:) PFE.N jabs and comes as the supply of shots from Astra starts to slow due to manufacturing issues including at a site in India."I'm delighted we can start the UK rollout of the Moderna vaccine in west Wales today," Hancock said. "Today we start with the third approved vaccine. Wherever you live, when you get the call, get the jab."Prime Minister Boris Johnson urged people to get their shots as soon as they were invited.The United Kingdom has vaccinated 31.6 million people with a first dose of a COVID-19 vaccine -...read more...