At home and cross after virus's arrival (6)
I believe the answer is:
influx
'arrival' is the definition.
(an influx means the arrival of lots of people)
'at home and cross after virus's' is the wordplay.
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'and' means one lot of letters go next to another.
'cross' becomes 'x' (X is cross-shaped).
'after' says to put letters next to each other.
'virus' becomes 'flu'.
'x' after 'flu' is 'flux'.
'in'+'flux' is 'INFLUX'.
(Other definitions for influx that I've seen before include "Inundation" , "Continual inflow" , "Sudden arrival in numbers" , "Process of arrival" , "Arrival in large numbers" .)