The coronavirus pandemic has caused backlogs in many areas of the NHS, including cancer and A&E.
It will serve self-isolation alerts based on logs of who the user was recently in close contact with.
Patients awarded thousands in compensation have not been paid as he did not have insurance.
But experts caution there are many other considerations, including cost and over-diagnosis.
Researchers hope the £8.4m study will show the long-term impact of Covid-19 and how to treat it.
Deaths recorded in England had included people who tested positive months before they died.
An NHS Confederation report predicts a 20% increase in demand for services in the coming months.
The home secretary says the "uncertain" law on the drug - often used by gay men during sex - may change.
Antibody tests suggest similar exposure to the virus in the two capitals, despite different strategies.
Health minister Edward Argar says it is "evolving and flexing", amid plans to cut 6,000 contact tracers.