LONDON, June 5, 2020 (Xinhua) -- British Prime Minister Boris Johnson delivers a speech to the virtual Global Vaccine Summit at 10 Downing Street in London, Britain, on June 4, 2020. British Prime Minister Boris Johnson opened the Global Vaccine Summit virtually on Thursday, urging countries and organizations to pledge funding for vaccinations to save millions of lives in the poorest countries and protect the world from future outbreaks of infectious diseases. Andrew Parsons/No 10 Downing Street/Handout