Differential impact of malaria control interventions on P. falciparum and P. vivax infections in young Papua New Guinean children

Table 1 Key predictors of infections due to P. falciparum and P. vivax as detected by qPCR in 2013

	P. falciparum				P. vivax
	Observed positive (%; n = 4363)	OR	CI₉₅	p	Observed positive (%; n = 4363)	OR	CI₉₅	p
Areas of residence
Ilahita 1–4, 6, 7	4.5	Reference group			6.1	Reference group
Balanga and Balif	4.6	1.01	0.59–1.72	0.969	6.0	0.98	0.51–1.88	0.946
Kamanokor and Ilahita 5	12.9	2.29	1.38–3.80	0.001	38.0	9.22	5.55–15.3	< 0.001
Sunuhu 1 and 2	28.8	7.63	5.34–10.9	< 0.001	45.2	13.7	8.81–21.3	< 0.001
			p < 0.0001^a				p < 0.0001^a
Age
Linear		2.91	1.26–6.70	0.012		1.32	1.16–1.51	< 0.001
Quadratic		0.88	0.78–0.99	0.032
ADI visit
Enrolment	18.4	Reference group			23.2	Reference group
Week 4	8.7	0.40	0.27–0.58	< 0.001	21.4	0.80	0.61–1.05	0.105
Week 8	8.7	0.39	0.19–0.46	< 0.001	21.3	0.85	0.65–1.11	0.238
Week 12	7.1	0.30	0.19–0.46	< 0.001	19.1	0.71	0.53–0.96	0.024
Week 16	8.1	0.34	0.22–0.53	< 0.001	17.8	0.65	0.49–0.88	0.004
Week 20	9.9	0.47	0.27–0.79	0.004	20.3	0.66	0.45–0.98	0.04
Week 24	7.6	0.31	0.19–0.52	< 0.001	21.8	0.83	0.59–1.19	0.312
Week 28	7.2	0.36	0.22–0.60	< 0.001	17.9	0.64	0.43–0.94	0.024
Week 32	8.8	0.40	0.25–0.65	< 0.001	18.1	0.57	0.40–0.83	0.004
Week 36	10.8	0.55	0.35–0.85	0.007	18.0	0.53	0.37–0.76	0.001
Week 40	32.2	3.20	2.15–4.74	< 0.001	22.9	0.82	0.56–1.19	0.298
			p < 0.0001^a				p = 0.0129^a
Haemoglobin		0.65	0.57–0.74	< 0.001
Recent antimalarial
No	11.5				20.3
Yes	21.3				15.0	0.34	0.17–0.71	0.004
Enlarged spleen
No	10.8				19.2
Yes	38.6				54.6	1.66	0.98–2.79	0.059
Febrile illness
No	10.9				19.7
Yes	25.0	1.84	1.30–2.62	0.001	29.2
^b2 weeks history of febrile illness
No	11.5				20.0
Yes	28.6	2.24	0.93–5.38	0.073	38.1	1.84	1.02–3.32	0.042

Multivariate GEE model-based estimates of risk of infection detected at each monthly active case detection visit time-point via backward selection of significant risk factors. OR multivariate adjusted odds ratio, CI₉₅ 95% confidence interval, p p value, ADI active detection of infection. ^aOverall significance level for the variable estimated using Wald chi-square test. ^bExcluding febrile illness at the time of visit

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