Crossword Genius

Tons running activity to track virus contacts (7)

Ross

I believe the answer is:

tracing

'activity to track virus contacts' is the definition.
(as in contact tracing)

'tons running' is the wordplay.
'tons' becomes 't'.
'running' becomes 'racing' ('race' can be a synonym of 'run').
't'+'racing'='TRACING'

(Other definitions for tracing that I've seen before include "Finding by investigation" , "design" , "Tracking or outlining on transparent paper" , "Hunting down" , "produce copy?" .)

I've seen this clue in The Times.
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