Table 1. Vaccine efficacy against all episodes of clinical and severe malaria in children aged 5–17 mo at enrollment.
| Type of Event (Up to Month 20) | RTS,S/AS01 Vaccine | Control Vaccine | Protective Efficacy | |||||||
| Number of Children | Number of Events | Person-Years | Event Rate or Affected Rate (Percent)1 | Number of Children | Number of Events | Person-Years | Event Rate or Affected Rate (Percent)1 | Percent (95% CI) | p-Value2 | |
| Clinical malaria—primary case definition 3 | ||||||||||
| Per-protocol population (18 mo after third dose of vaccine) | 4,557 | 4,257 | 6,186.0 | 0.69 | 2,328 | 3,639 | 3,100.4 | 1.17 | 45.7 (41.7 to 49.5) | <0.001 |
| ITT population (20 mo after first dose of vaccine) | 5,949 | 5,106 | 9,059.1 | 0.56 | 2,974 | 4,305 | 4,484.4 | 0.96 | 45.1 (41.4 to 48.7) | <0.001 |
| Clinical malaria—secondary case definition 4 | ||||||||||
| Per-protocol population (18 mo after third dose of vaccine) | 4,557 | 6,616 | 6,094.5 | 1.09 | 2,328 | 5,409 | 3,031.8 | 1.78 | 45.4 (41.6 to 48.9) | <0.001 |
| ITT population (20 mo after first dose of vaccine) | 5,949 | 8,207 | 8,939.1 | 0.92 | 2,974 | 6,482 | 4,400.6 | 1.47 | 43.1 (39.5 to 46.5) | <0.001 |
| Severe malaria without comorbidity 5 | ||||||||||
| Per-protocol population (18 mo after third dose of vaccine) | 4,557 | 120 | 2.6 | 2,328 | 95 | 4.1 | 35.5 (14.6 to 51.1) | 0.001 | ||
| ITT population (20 mo after first dose of vaccine) | 5,949 | 156 | 2.6 | 2,974 | 118 | 4.0 | 33.9 (15.3 to 48.3) | <0.001 | ||
| Malaria hospitalization 6 | ||||||||||
| Per-protocol population (18 mo after third dose of vaccine) | 4,557 | 236 | 5.2 | 2,328 | 206 | 8.8 | 41.5 (29.1 to 51.7) | <0.001 | ||
| ITT population (20 mo after first dose of vaccine) | 5,949 | 310 | 5.2 | 2,974 | 261 | 8.8 | 40.6 (29.7 to 49.8) | <0.001 | ||
| All-cause hospitalization 7 | ||||||||||
| Per-protocol population (18 mo after third dose of vaccine) | 4,557 | 706 | 15.5 | 2,328 | 445 | 19.1 | 19.0 (8.5 to 28.1) | <0.001 | ||
| ITT population (20 mo after first dose of vaccine) | 5,949 | 1,003 | 16.9 | 2,974 | 622 | 20.9 | 19.4 (10.8 to 27.1) | <0.001 | ||
Event rate for clinical malaria; affected rate (percent) for severe malaria and hospitalization.
For clinical malaria: p-value from negative binomial regression. For severe malaria, malaria hospitalization, and all-cause hospitalization: p-value from two-sided Fisher's exact test.
Clinical malaria primary case definition: illness in a child brought to a study facility with a measured temperature of ≥37.5°C and P. falciparum asexual parasitemia at a density of >5,000 parasites/mm3 or a case of malaria meeting the primary case definition of severe malaria.
Clinical malaria secondary case definition: illness in a child brought to a study facility with a measured temperature of ≥37.5°C or reported fever within the last 24 h and P. falciparum asexual parasitemia at a density of >0 parasites/mm3.
Severe malaria primary case definition: P. falciparum asexual parasitemia at a density of >5,000 parasites/mm3 with one or more markers of disease severity and without diagnosis of a coexisting illness. Markers of severe disease were prostration, respiratory distress, a Blantyre coma score of ≤2 (on a scale of 0 to 5, with higher scores indicating a higher level of consciousness), two or more observed or reported seizures, hypoglycemia, acidosis, elevated lactate level, or hemoglobin level of <5 g/dl. Coexisting illnesses were defined as radiographically proven pneumonia, meningitis established by analysis of cerebrospinal fluid, bacteremia, or gastroenteritis with severe dehydration.
Malaria hospitalization case definition: a medical hospitalization with confirmed P. falciparum asexual parasitemia at a density of >5,000 parasites/mm3.
All-cause hospitalization primary case definition: a medical hospitalization of any cause, excluding planned admissions for medical investigation/care or elective surgery and admissions for trauma.