Covid-19 daily dashboard amended to include reinfections

Illustration of Covid-19, created by the Centres for Disease Control and Prevention (CDC)

The UK Health Security Agency (UKHSA) is now including data on possible reinfections in its Covid-19 dashboard – the UK’s main source of information about the virus.

Positive tests for any variant of Covid-19 within a 90-day time period are now considered part of the same case episode, and positive tests outside those parameters are now considered as reinfection episodes.

This is an evolution of the previous UKHSA methodology whereby people who tested positive for Covid-19 were counted only once in case numbers published on the daily dashboard, when they first tested positive. Repeat positive tests were not included.

Reinfection data is now included within and also alongside infection totals for England and Northern Ireland.

As of 31 January, updated figures for England show 14,845,382 episodes of infection since the start of the pandemic with 588,114 (4.0%) reinfections added to the total case number for England, covering the whole pandemic.

The new data shows that reinfection rates averaged around 1.4% of cases until 16 November 2021, when a spike in infections took place following the emergence of the Omicron variant. 

Following that increase in the number of people infected, reinfections rose – with reinfections now representing around 10% of episodes per day.

Professor Steven Riley, UKHSA’s Director General of Data and Analytics, said: “Reinfection remained at very low levels until the start of the Omicron wave. 

“It is right that our daily reporting processes reflect how the virus has changed. We continue to see downward trends in case numbers and incidence of illness as we work to reduce the impact of the pandemic on our day-to-day lives. 

“With vaccination still a great defence against infection and illness, please get jabbed as soon as possible.

As part of the changes made, UKHSA has also checked existing surveillance data using ‘more accurate’ algorithms.

This has identified around 1.5% extra cases of infection that were previously removed as duplicates.