The Health and Safety Executive gives clear guidance on RIDDOR reporting of COVID-19.
In summary the guidance states;
“You should only make a report under RIDDOR when one of the following circumstances applies:
an accident or incident at work has, or could have, led to the release or escape of coronavirus (SARS-CoV-2). This must be reported as a dangerous occurrence
a person at work (a worker) has been diagnosed as having COVID-19 attributed to an occupational exposure to coronavirus. This must be reported as a case of disease
a worker dies as a result of occupational exposure to coronavirus. This must be reported as a work-related death due to exposure to a biological agent.”
It is useful to understand non-reportable examples:-
When COVID-19 is suspected but not confirmed
When COVID-19 has been verified by a registered medical practitioner but it was not contracted via work-related exposure or there is no reasonable evidence that it was contracted at work.
A social care worker is providing treatment or care to a patient or service user who is not known to be COVID-19 positive, but the patient or service user subsequently tests positive.
As you can see deciding on whether an event is reportable or not can be complex, relying on reasonable evidence on whether this is an occupational exposure or not.