Most vulnerable patients likely to need COVID-19 vaccine top-ups, says CMO People most susceptible to COVID-19 may have to be re-vaccinated regularly to maintain protection against the virus, England's chief medical officer has told MPs. by Luke Haynes Sign in to continue Sign In Email address Password Stay signed in Trouble signing in? Reset password: Click here Need help? Email us Register FREE Limited free articles a month Free email bulletins Register Now Register Now Take a 30-day trial Join MIMS now and pay nothing for the first 30 days Join GPOnline now and pay nothing for the first 30 days Sign Up Sign Up