LONDON - The world’s first COVID-19 human challenge trial is due to start in London next year, after the government announced £33.6 million (US$42.5 million) funding for the project. In the initial phase, the aim is to establish the dose of SARS-CoV-2 needed to cause infection and to characterize the immune response to virus. That will lead on to tests of individual COVID-19 vaccines, in which volunteers will be challenged with the effective dose of SARS-CoV-2 one month after inoculation.