Table 2. Quality assessment of the included trials.

Study, year	Randomization	Blinding	Placebo-controlled	Dropout (n)	Jadad score
Peterson et al., 2007	adequate	double-blind	yes	162	5
Abdool et al., 2010	unclear	double-blind	yes	6	4
Grant et al., 2010	adequate	double-blind	yes	48	5
Baeten et al., 2011	unclear	double-blind	yes	N/A	3
Van Damme et al., 2012	adequate	double-blind	yes	266	5
Thigpen et al., 2012	adequate	double-blind	yes	115	5
Choopanya et al., 2013	adequate	double-blind	yes	355	5

Note: Adequate if the allocation sequence was generated by a computer or random number table. Unclear if the trial was described as randomized, but the method used for the allocation sequence generation was not described; N/A, not available.