Only 22% of people testing positive for coronavirus reported having symptoms on the day of their test, according to the Office for National Statistics.


This hammers home the importance of "asymptomatic transmission" - spread of the virus by people who aren't aware they're carrying it. Health and social care staff appeared to be more likely to test positive.


This comes as deaths from all causes in the UK fell to below the average for the second week in a row. Between the end of March and June, there were 59,000 more deaths than the five-year average


While the ONS survey includes relatively small numbers of positive swab tests (120 infections in all) making it hard to make any strong conclusions about who is most likely to be infected, there are some patterns coming through in the data:


  • Those in people-facing health or social care roles, and working outside their homes in general, were more likely to have a positive test.
  • People from ethnic minority backgrounds were more likely to have a positive antibody test, suggesting a past infection.
  • White people were the least likely proportionally to test positive for antibodies.
  • There was also some evidence that people living in larger households were more likely to test positive than those in smaller households.


Although men are more likely to die from coronavirus than women, this study did not find a difference in how likely they were to contract the infection.


The figures are based on tests of people selected at random in homes in England - people living in care homes or other institutions are not included in this study. Some people testing positive without symptoms might go on to develop symptoms, or they may have already had symptoms and cleared them.


The prime minister talked about how asymptomatic spread may have contributed to coronavirus cases in care homes.


His comments provoked anger in the care home sector when he suggested, "too many care homes didn't really follow the procedures". His Business Secretary Alok Sharma later said he'd meant that "nobody at the time knew what the correct procedures were", because of a lack of understanding of levels of asymptomatic transmission at the start of the outbreak.


Asymptomatic transmission was warned of by the World Health Organization and the government's scientific advisors, but they weren't able to quantify how great a risk it was.