Table 2.
Incidence of infection during household survey visits and symptomatic clinic visits, by Plasmodium species
| Survey population | Clinic subpopulation | |||||
|---|---|---|---|---|---|---|
| At-risk pop. n | Cumulative events (infections)a | Crude risk (%) (95% CI) | At-risk pop.b n | Cumulative events (infections)a,c | Crude risk (%) (95% CI) | |
| P. malariae | ||||||
| Baseline | 1518 | 0 | 1002 | 0 | ||
| Month 6 | 1398 | 20 | 1.4 (0.8–2.1) | 934 | 24 | 2.5 (1.5–3.5) |
| Month 12 | 1230 | 67 | 4.9 (3.7–6.0) | 910 | 48 | 5.0 (3.6–6.4) |
| Month 18 | 744 | 86 | 7.0 (5.5–8.4) | 890 | 68 | 7.1 (5.5–8.7) |
| Month 24 | -- | -- | -- | 875 | 83 | 8.7 (6.9–10.4) |
| P. ovale spp. | ||||||
| Baseline | 1559 | 0 | 1001 | 0 | ||
| Month 6 | 1425 | 23 | 1.6 (1.0–2.3) | 990 | 12 | 1.2 (0.5–1.9) |
| Month 12 | 1279 | 49 | 3.4 (2.4–4.3) | 972 | 30 | 3.0 (1.9–4.0) |
| Month 18 | 769 | 55 | 4.1 (3.0–5.1) | 951 | 51 | 5.1 (3.7–6.4) |
| Month 24 | -- | -- | -- | 938 | 64 | 6.4 (4.9–7.9) |
| P. falciparum | ||||||
| Baseline | 1081 | 0 | 662 | 0 | ||
| Month 6 | 774 | 227 | 22.5 (19.9–25.0) | 520 | 143 | 21.6 (18.4–24.6) |
| Month 12 | 529 | 423 | 42.8 (39.6–45.8) | 323 | 341 | 51.4 (47.5–55.1) |
| Month 18 | 167 | 458 | 51.4 (47.6–55.0) | 238 | 425 | 64.1 (60.3–67.6) |
| Month 24 | -- | -- | -- | 211 | 452 | 68.2 (64.4–71.5) |
CI confidence interval.
aCumulative first infections detected. Time to the first incident infection event.
bThe at-risk population for the clinic subpopulation comprises subjects who were PCR-negative for each species-specific infection at baseline and had at least one visit to study health clinics during the follow-up period.
cIncludes infections detected only at symptomatic clinic visits.