Can changes in malaria transmission intensity explain prolonged protection and contribute to high protective efficacy of intermittent preventive treatment for malaria in infants?

Table 3 Modelled and actual protective efficacy to 12 months of age in each IPTi trials

	Input					Output
Study Site	Age of SP IPTi administration (months)	Mean incidence in placebo group (episodes per person year) (λ (a)/2)	ITN coverage (%)	Estimated*** cross sectional prevalence parasitaemia at start of study (%)	Estimated Day 28 ACPR for SP ( σ × 100)	Model estimate of PE (%)	Actual PE of IPTi (% 95% CI)	Ratio model:study
Ifakara	2,3 and 9	0.54	67	4.5	60	23.0	58.8 (40.8–71.3)	0.39
Navrongo	2,4,9 and 12	1	18	8.3	65*	31.9	29.3 (17.7–39.5)	1.09
Mahnica	3,4 and 9	0.71	0	5.9	65*	32.0	20.1 (2.1–34.9)	1.59
Kumasi	3,9 and 15	1.27	20	10.6	69**	25.9	20.9 (8.9–31.3)	1.24
Tamale	3,9 and 15	0.93	1	7.8	69	24.9	33.3 (20.7–43.8)	0.75
Lamberene	3,9 and 15	0.16	5	1.3	65*	23.7	22.0 (-25.4–51.5)	1.08

* Estimated from Day 14 ACPR, ** Estimated from Tamale data.
*** Starting Cross sectional parasite prevalence (asymptomatic infected children) estimated from mean monthly incidence in placebo group Incidence and PE figures from IPTi Consortium Statistical Working Group Report September 2007 (Aponte JJ et al. In preparation)

ISSN: 1475-2875