Summary of findings 1. Inhaled corticosteroids plus standard care compared to standard care (with or without placebo) for adults with a confirmed diagnosis of mild COVID‐19.

Inhaled corticosteroids plus standard care compared to standard care (with or without placebo) for adults with a confirmed diagnosis of asymptomatic SARS‐CoV‐2 infection or mild COVID‐19
Patient or population: adults with a confirmed diagnosis of mild COVID‐19, of whom only 10% (219/2132) participants had received ≥ 1 vaccination Setting: outpatient Intervention: inhaled corticosteroids plus standard care Comparison: standard care (with or without placebo)
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Certainty of the evidence (GRADE)	Comment
	Risk with standard care (with or without placebo)a	Risk with inhaled corticosteroids (plus standard care)
All‐cause mortality Follow‐up: at up to 30 days	9 per 1000	6 per 1000 (2 to 16)	RR 0.61 (0.22 to 1.67)	2132 (3 studies)	⊕⊕⊖⊖ Lowb	Inhaled corticosteroids may result in little to no difference in all‐cause mortality up to day 30.
Admission to hospital or death Follow‐up: at up to 30 days	79 per 1000	57 per 1000 (40 to 78)	RR 0.72 (0.51 to 0.99)	2025 (2 studies)	⊕⊕⊕⊖ Moderatec	Inhaled corticosteroids probably reduce the risk of admission to hospital or death up to day 30.
Symptom resolution: all initial symptoms resolved at day 14	465 per 1000	553 per 1000 (507 to 605)	RR 1.19 (1.09 to 1.30)	1986 (2 studies)	⊕⊕⊕⊖ Moderated	Inhaled corticosteroids probably increase the resolution of all initial symptoms at day 14.
Symptom resolution: duration to symptoms resolved Follow‐up: at up to day 30	The mean duration to symptoms resolved was 12.00 days.	The mean duration of symptoms resolved was 8.00 days (5.78 to 10.22 days).	MD −4.00 days (−6.22 to −1.78)	139 (1 study)	⊕⊕⊖⊖ Lowd,e	Inhaled corticosteroids may decrease the duration to symptom resolution.
Serious adverse events Follow‐up: during study period	5 per 1000	3 per 1000 (0 to 14)	RR 0.51 (0.09 to 2.76)	1586 (1 study)	⊕⊖⊖⊖ Very Lowb,d	The evidence is very uncertain about the effect of inhaled corticosteroids on serious adverse events.
Adverse events Follow‐up: at up to day 30	143 per 1000	111 per 1000 (67 to 187)	RR 0.78 (0.47 to 1.31)	400 (1 study)	⊕⊕⊖⊖ Lowd,e	Inhaled corticosteroids may result in little to no difference in adverse events.
Infections Follow‐up: during study period	34 per 1000	30 per 1000 (10 to 89)	RR 0.88 (0.30 to 2.58)	400 (1 study)	⊕⊕⊖⊖ Lowb	Inhaled corticosteroids may result in little to no difference in infections.
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention group (and its 95% CI). CI: confidence interval; MD: mean difference; RR: risk ratio.
GRADE working group grades evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.

^aControl group risk estimated from included studies (with 10% of participants being vaccinated at least once).
^bDowngraded two levels for very serious imprecision (very low number of events, wide CI).
^cDowngraded one level for serious imprecision (low number of participants/events and optimal information size would be 3764 participants).
^dDowngraded one level for serious risk of bias (partly measurement of the outcome affected by unblinded design, selection of the reported result, missing outcome data as the safety‐relevant outcome was not reported) and reporting bias (the safety‐relevant outcome was not reported).
^eDowngraded one level for serious imprecision (low number of participants/events and wide CI).