TABLE 2.

Meta-regression model results estimating the effect of strain type, comparing partially heterotypic and fully heterotypic to homotypic.

RV1/ RV5	Income level	Strain category	Specific strains (No. of studies)	Odds ratio (95% CI)	Vaccine effectiveness (95% CI)	Absolute difference in the VE (95%*)	Ratio of the pooled ORs (95% CI)	p-value
RV1	High	Homotypic	G1P[8] (N = 5)	0.10	90	REF	REF
				(0.06, 0.18)	(82, 94)
		Partially heterotypic	G3P[8] (N = 4), G4P[8] (N = 1), G8P[8] (N = 1), G9P[8] (N = 2), G12P[8] (N = 2)	0.20	79	–10.2%	1.98	0.04
				(0.14, 0.29)	(71, 85)	(–20.8, –2.6)	(1.04, 3.77)
		Fully heterotypic	G2P[4] (N = 5)	0.20	80	–9.6%	1.93	0.10
				(0.11, 0.35)	(65, 88)	(–27.0, 1.4)	(0.88, 4.22)
	Middle	Homotypic	G1P[8] (N = 4)	0.19	81	REF	REF
				(0.12, 0.31)	(69, 88)
		Partially heterotypic	G3P[8] (N = 2), G4P[8] (N = 1), G9P[8] (N = 4), G12P[8] (N = 2)	0.33	67	–13.9%	1.71	0.06
				(0.24, 0.46)	(54, 76)	(–29.8, 5.2)	(0.97, 3.01)
		Fully heterotypic	G2P[4] (N = 10)	0.35	65	–15.8%	1.81	0.04
				(0.25, 0.49)	(51, 75)	(–34.6, 0.6)	(1.02, 3.21)
	Low	Homotypic	G1P[8] (N = 2)	0.20	80	REF	REF
				(0.08, 0.50)	(50, 92)
		Fully heterotypic	G2P[4] (N = 1)	0.65	35	–44.7% (NC†)	3.18	0.19
				(0.18, 2.35)	(–135, 82)		(0.57, 17.80)
RV5	High	Homotypic	G1P[8] (N = 7), G3P[8] (N = 4)	0.12	88	REF	REF
				(0.08, 0.16)	(84, 92)
		Partially heterotypic	G2P[4] (N = 5), G9P[8] (N = 2), G12P[8] (N = 3)	0.18	82	–6.2%	1.54	0.08
				(0.13, 0.24)	(76, 87)	(–13.0, 0.01)	(0.94, 2.52)
	Middle	Homotypic	G1P[8] (N = 2), G3P[8] (N = 1)	0.45	55	REF	REF
				(0.26, 0.76)	(24, 74)
		Partially heterotypic	G2P[4] (N = 2), G12P[8] (N = 1)	0.48	52	–3.0%	1.06	0.86
				(0.30, 0.77)	(23, 70)	(–28.1, 32.1)	(0.54, 2.10)

*Confidence intervals for the absolute difference in the VE calculated using bootstrapping estimation with 1000 resamples.

†NC = not calculable due to limited number of studies