TABLE 1 |.

Study characteristics and methods of swab collection.

	Study design	Study setting	Study population	Specimen type	GA (weeks) at swab collection	Participant characteristics examined	ART at conception	DNA extraction
Short et al. (2021) [24]	Prospective observational	HIV specialist & general antenatal clinics of ten London hospitals (UK)	53 PWLWH 22 HUPW	High vaginal swab. Soft cup for CVF in PWLWH	For PWLWH T1: 16.0–21.9 T2:22.0–26.9 T3: 27–31.9 For HUPW vaginal sampling occurred at one second trimester time point	Maternal age Ethnicity BMI Smoker Parity PTB risk factors Birth outcome	n = 41/53	16s rRNA gene amplification at V1-V2 hypervariable regions
Price et al. [14]	Prospective cohort	Women & newborn hospital of the UTH in Lusaka (Zambia)	Total participants n = 461 Lost to follow up 88 HIV−ve 278 (term n = 259, sPTB n = 19) HIV +ve n = 85 (term n = 75, sPTB n = 10)	Mid vaginal swab	Between 16 and 20 mean GA at first sample collection was 18 weeks (IQR: 17–19). Repeat specimen collection at 32 weeks for random subset of 66 PWLWH. 47 (71%) of these had cytokine analysis	Maternal age BMI GA Parity HIV seropositive Preconceptional ART	n = 85 n = 44/75 (term) n = 6/10(sPTB)	(WGS)sequencing
Gudza-Mugabe et al. [29]	Prospective cohort	Harare & Chitungwiza central hospital antenatal clinics (Zimbabwe)	Eligible women = 420 Overall = 356 passed sequencing quality control PWLWH = 42	2 vaginal swabs at single time	29 weeks, IQR (25–33)	Maternal age GA Partner smoker ART regimen Gravida Parity Blood CD4 Plasma VL	n = 40/42 TDF, FTC, EFV (36) AZT+3TC (4)	16s rRNA gene amplification

Abbreviations: UTH, university teaching hospitals; WGS, whole genome shotgun.