Long-term safety and efficacy of the RTS,S/AS02A malaria vaccine in Mozambican children.
BACKGROUND
We previously reported that the RTS,S/AS02A vaccine had an acceptable safety profile, was immunogenic, and demonstrated efficacy against Plasmodium falciparum malaria disease for 21 months.


METHODS
We conducted a randomized, controlled, phase 2b trial of RTS,S/AS02A in 2022 Mozambican children aged 1-4 years. We now report safety results for all randomized subjects and vaccine efficacy (VE) findings for children in the Manhiça area over the 45-month surveillance period.


RESULTS
During the surveillance period, the VE((2.5-45)) (VE over months 2.5-45 of surveillance) against a first or only episode of clinical malaria disease was 30.5% (95% confidence interval [CI], 18.9%-40.4%; P < .001), and the VE((2.5-45)) against all episodes was 25.6% (95% CI, 11.9%-37.1%; P < .001). When the same period was considered, the VE((2.5-45)) for subjects protected against severe malaria was 38.3% (95% CI, 3.4%-61.3%; P = .045). At study month 45, the prevalence of P. falciparum was 34% lower in the RTS,S/AS02A group than in the control group (66 [12.2%] of 541 patients vs 101 [18.5%] of 547 patients) (P = .004).


CONCLUSIONS
These results show evidence that RTS,S/AS02A maintained protection during the 45-month surveillance period, and they highlight the feasibility of developing an effective vaccine against malaria. In combination with other malaria-control measures, such a vaccine could greatly contribute to reducing the intolerable global burden of this disease. Trial registration. ClinicalTrials.gov identifiers NCT00197041 and NCT00323622 .
Sacarlal
Jahit
J
Centro de Investigação em Saúde de Manhiça (CISM) Manhiça, Mozambique. jahit.sacarlal@manhica.net
Aide
Pedro
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Aponte
John J
JJ
Renom
Montse
M
Leach
Amanda
A
Mandomando
Inácio
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Lievens
Marc
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Bassat
Quique
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Lafuente
Sarah
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Macete
Eusébio
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Vekemans
Johan
J
Guinovart
Caterina
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Sigaúque
Betuel
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Sillman
Marla
M
Milman
Jessica
J
Dubois
Marie-Claude
MC
Demoitié
Marie-Ange
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Thonnard
Joelle
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Menéndez
Clara
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Ballou
W Ripley
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Cohen
Joe
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Alonso
Pedro L
PL
D000913:Antibodies, Protozoan / Q000097:blood; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D017780:Malaria Vaccines / Q000009:adverse effects* / Q000276:immunology / Q000592:standards*; D016778:Malaria, Falciparum / Q000276:immunology / Q000517:prevention & control*; D009073:Mozambique / Q000453:epidemiology; D018512:Parasitemia; D013997:Time Factors
D000913:Antibodies, Protozoan; D017780:Malaria Vaccines