. 2020 May 20;3(1):74–92. doi: 10.1136/bmjnph-2020-000085

Table 2.

Summary of selected systematic reviews and meta-analyses reporting on probiotics and respiratory infections

Authors	Population	Included trials	Probiotic	Outcome	Effect
Vouloumanou et al ²⁰⁷	Children and adults	14 RCTs (3580 participants)	Any (mainly lactobacilli and bifidobacteria)	RTI	4/10 RCTs reported probiotics reduced incidence of RTI 5/6 RCTs reported probiotics reduced severity of symptoms of RTI 3/9 RCTS reported probiotics shortened duration of RTI
Liu et al ²⁰⁸	Critically ill adults	12 RCTs (1546 patients)	Any	Nosocomial pneumonia	OR of nosocomial pneumonia with probiotics 0.75 (95% CI 0.57 to 0.97) No effect of probiotics on in hospital mortality, intensive care unit mortality, duration of hospital stay, duration of intensive care unit stay
Liu et al ²⁰⁹	Children	4 RCTs (1805 children)	Lactobacillus rhamnosus GG	RTI	RR of URTI with probiotics 0.62 (95% CI 0.50 to 0.78) RR for antibiotic treatment for URTI with probiotics 0.80 (95% CI 0.71 to 0.91) No effect of probiotics on LRTI or overall respiratory infections
King et al ²¹⁰	Children and adults	20 RCTs (>4141 participants)	Any	RTI	SMD days of illness per person with probiotics −0.31 (95% CI −0.41 to −0.11); WMD days of illness with probiotics −0.77 (95% CI −1.50 to −0.04); SMD days of absence with probiotics −0.17 (95% CI −0.31 to −0.03)
Hao et al ²¹¹	Children and adults	13 RCTs; 12 RCTS in meta-analysis (3750 participants)	Any	URTI	OR of one URTI with probiotics 0.53 (95% CI 0.37 to 0.76) OR of at least three URTIs with probiotics 0.53 (95% CI 0.36 to 0.80) Mean duration of episode of URTI with probiotics −1.89 days (95% CI −2.03 to −1.75) OR for antibiotic prescription for URTI with probiotics 0.65 (95% CI 0.45 to 0.94)
Ozen et al ²¹²	Children	14 RCTs	Any (mainly lactobacilli and bifidobacteria)	URTI	At least one beneficial effect of probiotics was observed in most of the RCTs
Araujo et al ²¹³	Children	11 RCTs (2417 children)	Any	RTI	Several RCTs reports fewer new episodes, decreased duration of episodes and less severe symptoms
Wang et al ²¹⁴	Children	23 RCTs (6269 children)	Any	RTI	RR of one RTI with probiotics 0.80 (95% CI 0.82 to 0.96); Days of RTI per child with probiotics −0.16 (95% CI −0.29 to 0.02) Days absent with probiotics −0.94 (95% CI −1.72 to −0.15)
Laursen and Hojsak²¹⁵	Children	15 RCTs; 12 RCTs in meta-analysis (4527 children)	Any	RTI	L. rhamnosus GG reduced duration of RTI −0.78 days (95% CI −1.46 to −0.090) Meta-analysis for other probiotics is not possible

LRTI, lower respiratory tract infection; RCT, randomised controlled trial; RR, relative risk; RTI, respiratory tract infection; SMD, standardised mean difference; URTI, upper respiratory tract infection; WMD, weighted mean difference.