From 31 January 2022, UKHSA will move all COVID-19 case reporting in England to use a new episode-based definition which includes possible reinfections.
On the dashboard, this means:
- cases in England by report date will change to the new definition of an episode of infection
- historical numbers by report date will not be revised, so there will be a step increase in the cumulative numbers of cases on that date
- specimen date metrics will be revised back to the beginning of the pandemic.
- the same metric names will still be used
- new metrics will show first episodes of infection (equivalent to the current case definition) and episodes of reinfection, shown by specimen date only.
UKHSA is working with the devolved administrations to align definitions across the UK.
Additional details
As the pandemic continues and more variants emerge, it is more likely that people will be reinfected with COVID-19.
Contact tracing and health protection work at UKHSA follows up people with a positive test result, whether they were a new case or a case of reinfection. However, surveillance figures only report COVID-19 cases as the date of the first infection, so individuals are only counted once.
UK public health agencies are now updating surveillance data to count infection episodes, including reinfection episodes.
Infection episodes will be counted separately if there are at least 90 days between positive test results.
Each episode begins with the earliest positive specimen date. If someone has another positive specimen within 90 days of the last one, this is included in the same episode. If they have another positive specimen more than 90 days after the last one, this is counted in a separate episode (a possible reinfection episode).
