How do we know if vaccine is working?

More than 18 million people in the UK have received a first dose of coronavirus vaccine - but how will we know if it’s working? There are some early signs of a possible vaccine effect in falling deaths among people aged over 80. But data on cases and hospital patients is not so clear

WHAT DOES THE DATA SHOW?

Analysis suggests the vaccine is starting to push the numbers down.

● Coronavirus deaths are falling faster for vaccinated than unvaccinated groups.

● On average, deaths of over-80s fell by 53% between January 28 and February 11, compared with 44% for under-80s.

● Hospital admissions for over-85s dropped by 45% between January 30 and February 13, compared with 42% for under-85s. The number of coronavirus cases is also falling slightly faster for older people compared with other age groups. Between January 28 and February 11, cases in over-80s fell by 52% compared with 47% in under-80s. But case numbers might not be a reliable indicator of whether the vaccine is working.

The vaccine prevents serious infections.

But the large number of routine coronavirus tests in settings such as care homes will also pick up mild and asymptomatic infections.