Table 2.

Participant characteristics of included studies (N=41)

		Count of studies	% of studies
Sample size	≤500	14	34%
	501–≤1000	6	15%
	1001–≤3000	12	29%
	3001+	9	22%
Eligible age group included (years)	≥60	7	17%
	≥65	34	83%
% female	≤50%	8	20%
	51%–60%	19	46%
	61%–75%	11	27%
	Not reported	3	7%
Race	Reported races other than white/Caucasian*	19	46%
	Reported race as only white/Caucasian	8	20%
	Not reported	14	34%
Vaccination history	≤60%	2	5%
	61%–80%	3	7%
	81%–100%	7	17%
	Not reported	29	71%
Frailty history	Yes	3	7%
	Not reported	38	93%
Comorbidities	Reported >2 comorbidities	9	22%
	Reported a comorbidity score	4	10%
	Not reported	28	68%

*White/Caucasian race in these studies ranged between 0% and 98%.