IL6 and lymphopenia: Compared to participants with no lymphopenia and resolved lymphopenia, participants with persistent or new lymphopenia were on average more commonly older, male, infected between July and December 2021 (delta variant predominant), had more vaccine doses (reflecting the more recent era in which they were enrolled), had a history of renal impairment, N Ag >/=1000 ng/L, higher oxygen requirement, eGFR < 60 ml/min/1.73m2, CRP > 7.5 mg/L, and IL-6 > 5.8 ng/L, and those with new lymphopenia had the highest proportion of participants with IL-6 > 5.8 ng/ml (Table 1).