Comparing SARS-CoV-2 Viral Load in Human Saliva to Oropharyngeal Swabs, Nasopharyngeal Swabs, and Sputum: A Systematic Review and Meta-Analysis

Table 3

Study characteristics of SARS-CoV-2 viral load in saliva indicated by C_T values.

Author	Reference	Study design	Viral load (CT value) in saliva	SD and IQR	Method to detect viral load	Saliva sample source	% SARS-CoV-2 positive	Total cohort size	Days onset	Symptomatic	Asymptomatic
Azzi (2020)	[37]	Cross-sectional	Mean: 27.16	SD: 3.07	RT-PCR	Drooling (excludes mucous secretions from oropharynx and lower respiratory tracts)	100%	25	0–4	NR	NR
Barat (2021)	[31]	Cross-sectional	Median: 31	IQR: 29–37	RT-PCR	Drooling without restriction on timing or intake of food	6.5%	459	NR	NR	NR
			Mean: 32.4	SD: 6.2
Basso (2021)	[11]	Prospective cohort	Median: 28.6	IQR: 23.4–32.9	rRT-PCR	Self-collected by the Salivette device (SARSTEDT AG and co, Nümbrecht, Germany), the cotton swab being chewed for at least one minute to stimulate salivation	52.8% (in-patients)	138 (in-patients)	0–7	NR	NR
			Mean: 28.3	SD: 7.2			4.2% (outpatients)	96 (outpatients)
Bordi (2020)	[38]	Prospective cohort	Median: 32.3	IQR: 11–45	RT-PCR	Drooling, at least 30 min after drinking or eating or washing teeth	53%	164	0–100	n = 12	n = 14
			Mean: 29.3	SD: 25.6
Echavarria (2021)	[33]	Prospective cohort	Median: 26.1	IQR: 22.75–30.06	RT-PCR	Self-collection in plastic sterile container	35.1%	174	2	NR	NR
			Mean: 26.3	SD: 7.4
Seneviratne (2020)	[39]	Randomized control trial	Mean: 27.7	SD: 4.8	RT-PCR	Drooling, refrain from eating, drinking, or performing oral hygiene procedures for at least 30 min	44.4%	36	0–2	NR	NR

All median values, if present, are original and obtained from the publication. Authors were contacted for the original dataset. NR = not reported, ND = not detected, SD = standard deviation, and IQR = interquartile range.