Thousands of volunteers will receive a booster COVID-19 vaccine in a new clinical trial launching on 19 May to study the impact of the third jab to protect against the deadly virus, the UK Health Secretary has announced.

For our comprehensive coverage and latest updates on COVID-19 click here.

The Cov-Boost study will trial seven vaccines to provide data on the impact of the third dose on patients' immune responses, as Britain confirmed 2,967 cases of the B1.617.2 variant first discovered in India up from the 2,323 on 17 May. During a briefing from 10 Downing Street in London, the health secretary reiterated the UK Prime Minister's earlier statement from the House of Commons that there is increasing confidence that the vaccines currently being administered are effective against the B1.617.2 variant, which has been found to be more easily transmissible from person to person. Strong evidence shows the vaccines protect you and your loved ones from serious illness and they also reduce transmission, which is why we've introduced additional surge measures in the areas with rising cases of the variant first identified in India, said the UK health secretary.

Vaccines are turning the tide against this pandemic and I'm incredibly proud the UK has one of the highest uptake rates in the world, with 90 per cent of people saying that they have had or will have the jab, he said. Relaying the latest data, the health minister said that hospitalisations and deaths from COVID-19 remain very low but there was a need to proceed with vigilance.  The Cov-Boost study will be led by University Hospital Southampton NHS Foundation Trust and backed by 19.3 million pounds of government funding through the Vaccines Taskforce.

All participants will be monitored throughout the study for any side effects and will have blood taken to measure their immune responses at days 28, 84, 308 and 365, with a small number having additional blood tests at other times. All sites will have an electronic diary for all participants that will send alerts to the team in real-time if needed and a 24-hour emergency phone to a doctor on the study, who can provide further clinical advice.

The initial findings, expected in September, will help inform decisions by the Joint Committee on Vaccination and Immunisation (JCVI) on plans for a booster programme from autumn this year, ensuring the country's most vulnerable are given the strongest possible protection over the winter period.