Additional file 1: of Evaluation of the impact of disease prevention measures: a methodological note on defining incidence rates

“Time not at risk” and its approximation. Derivation of the equations for approximating time not at risk. (DOCX 33 kb

Protective efficacy of individual IPT doses against clinical malaria.

<p>Protective efficacy against first-or-only episode of clinical malaria (history of fever or temperature ≥37.5°C plus malaria parasites detected on a blood smear) by week since treatment for IPTi doses 2, 3 & 4.</p>*<p>No children given SP had malaria during week 2 after IPT4.</p

Timely completion for each actual dose and cumulatively¹.

<p>¹55 patients were excluded from this analysis because data on timing of each actual dose were not possible to assess for self-report for 18 patients and for smart blister pack data for 37 patients.</p

Completed treatment by self-report and smart blister packs.

<p>¹An odds ratio for the effect of measurement method on completed treatment could not be calculated because there were zero patients who reported completing treatment but did not complete treatment by smart blister pack data.</p><p>Completed treatment by self-report and smart blister packs.</p

Protective efficacy of individual IPT doses against clinical malaria.

<p>Protective efficacy against first-or-only episode of clinical malaria (history of fever or temperature ≥37.5°C plus malaria parasites detected on a blood smear) by week since treatment for IPTi doses 2, 3 & 4. Error bars indicate 95% confidence intervals. The y-axis is truncated at −100 for IPT2 and IPT3, and at −150 for IPT4. No children given SP had malaria during week 2 after IPT4.</p

Flow chart of patients included in analysis.

<p>Flow chart of patients included in analysis.</p

Timely completion by self-report and smart blister packs¹ (percent (number)).

<p>¹55 patients were excluded from this analysis because data on timing of each actual dose were not possible to assess for self-report for 18 patients and for smart blister pack data for 37 patients.</p><p>²“Actual doses” refers to pills actually taken together, including pills that were not grouped together, or a different number than specified for the intended dose. Pills administered at least 30 minutes apart from each other were considered different actual doses.</p><p>³ By self-report, number of pills taken missing for one dose for 2 patients for the 1x6 pack, 1 patient for the 2x6 pack, and 8 patients for the 4x6 pack.</p><p>⁴ By self-report, time of taking one or more doses missing for 24 patients for the 1x6 pack, 12 patients for the 2x6 pack, 2 patients for the 3x6 pack, and 20 patients for the 4x6 pack.</p><p>⁵By smart blister pack data, no patients who completed treatment and took more than six actual doses took the first six at the correct intervals.</p><p>⁶ For all patients (total columns) the odds ratio for timely completion by smart blister pack vs. self-report was 0.36, 95% CI: 0.29, 0.42; p<0.0001.</p><p>Timely completion by self-report and smart blister packs<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134275#t003fn001" target="_blank">¹</a> (percent (number)).</p

Protective efficacy of IPT against high parasite density malaria.

<p>Protective efficacy of IPTi by week since treatment against high parasite density malaria (clinical malaria with parasite density ≥5000/µl). Error bars indicate 95% confidence intervals. PE estimates are for all IPT doses combined; all episodes that occurred before two years of age were included in the analysis. No long term protection was observed; for brevity estimates are presented up to twenty weeks following treatment. Incidence in weeks 13–16 and 17–20 was aggregated; data points are shown at the midpoint of each interval.</p

Effect of parasitaemia on protective efficacy following IPT.

<p>Protective efficacy against clinical malaria (history of fever or temperature ≥37.5°C plus malaria parasites detected on a blood smear) with time in children aparasitaemic (A) and parasitaemic (B) at time of IPT. Error bars indicate 95% CIs. PE estimates are for all IPT doses combined; all episodes that occurred before two years of age after an IPT dose at which a blood slide was taken were included. No long term protection was observed; for brevity estimates are presented up to twenty weeks following treatment. Incidence in weeks 13–16 and 17–20 was aggregated; data points are shown at the midpoint of each interval. For clarity of presentation the y-axis is truncated at −100%.</p

Number of actual doses taken by self-report and smart blister packs^1–3.

<p>¹55 patients were excluded from this analysis because data on timing of each actual dose were not possible to assess for self-report for 18 patients and for smart blister pack data for 37 patients. ²“Actual doses” refers to pills actually taken together, including pills that were not grouped together, or a different number than specified for the intended dose. Pills administered at least 30 minutes apart from each other were considered different actual doses. ³By self-report, patients were asked only about each of the six intended doses.</p