covid-19October 20, 2020 Healthy volunteers look set to be infected with Covid as part of new U.K. ‘challenge trial’ Supporters say the trials can be quicker than regular vaccine tests, while critics argue too little is known about the coronavirus to make them safe. Related posts U.K.'s Johnson launches mass testing…Do you need a Covid-19…What's behind workers' hesitation to…Fully vaccinated people can travel…Younger Latino men are Covid's…Salmonella infections in eight states…Salmonella infections in eight states…The U.S. isn't losing to…Virus-killing robot tested for use…In Covid fight, Cuba touts…