dc.contributor |
Universitat de Barcelona |
dc.contributor.author |
Guinovart, Caterina |
dc.contributor.author |
Aponte, John J. |
dc.contributor.author |
Sacarlal, Jahit |
dc.contributor.author |
Aide, Pedro Carlos Paulino |
dc.contributor.author |
Leach, Amanda |
dc.contributor.author |
Bassat Orellana, Quique |
dc.contributor.author |
Macete, Eusébio |
dc.contributor.author |
Dobaño, Carlota, 1969- |
dc.contributor.author |
Lievens, Marc |
dc.contributor.author |
Loucq, Christian |
dc.contributor.author |
Ballou, W. Ripley |
dc.contributor.author |
Cohen, Joe |
dc.contributor.author |
Alonso, Pedro |
dc.date |
2016-03-01T11:05:25Z |
dc.date |
2016-03-01T11:05:25Z |
dc.date |
2009-04-14 |
dc.date |
2016-03-01T11:05:30Z |
dc.identifier.citation |
1932-6203 |
dc.identifier.citation |
573186 |
dc.identifier.uri |
http://hdl.handle.net/2445/96008 |
dc.format |
8 p. |
dc.format |
application/pdf |
dc.language.iso |
eng |
dc.publisher |
Public Library of Science (PLoS) |
dc.relation |
Reproducció del document publicat a: http://dx.doi.org/10.1371/journal.pone.0005165 |
dc.relation |
PLoS One, 2009, vol. 4, num. 4, p. e5165 |
dc.relation |
http://dx.doi.org/10.1371/journal.pone.0005165 |
dc.rights |
cc-by (c) Guinovart, C. et al., 2009 |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.rights |
http://creativecommons.org/licenses/by/3.0/es |
dc.subject |
Vacuna de la malària |
dc.subject |
Infants |
dc.subject |
Moçambic |
dc.subject |
Assaigs clínics |
dc.subject |
Malaria vaccine |
dc.subject |
Children |
dc.subject |
Mozambique |
dc.subject |
Clinical trials |
dc.title |
Insights into long-lasting protection induced by RTS,S/AS02A malaria vaccine: further results from a phase IIb trial in Mozambican children |
dc.type |
info:eu-repo/semantics/article |
dc.type |
info:eu-repo/semantics/publishedVersion |
dc.description.abstract |
Background: The pre-erythrocytic malaria vaccine RTS,S/AS02A has shown to confer protection against clinical malaria for at least 21 months in a trial in Mozambican children. Efficacy varied between different endpoints, such as parasitaemia or clinical malaria; however the underlying mechanisms that determine efficacy and its duration remain unknown. We performed a new, exploratory analysis to explore differences in the duration of protection among participants to better understand the protection afforded by RTS,S. Methodology/Principal Findings: The study was a Phase IIb double-blind, randomized controlled trial in 2022 children aged 1 to 4 years. The trial was designed with two cohorts to estimate vaccine efficacy against two different endpoints: clinical malaria (cohort 1) and infection (cohort 2). Participants were randomly allocated to receive three doses of RTS,S/AS02A or control vaccines. We did a retrospective, unplanned sub-analysis of cohort 2 data using information collected for safety through the health facility-based passive case detection system. Vaccine efficacy against clinical malaria was estimated over the first six-month surveillance period (double-blind phase) and over the following 12 months (single-blind phase), and analysis was per-protocol. Adjusted vaccine efficacy against first clinical malaria episodes in cohort 2 was of 35.4% (95% CI 4.5-56.3; p = 0.029) over the double-blind phase and of 9.0% (230.6-36.6; p = 0.609) during the single-blind phase. Conclusions/Significance: Contrary to observations in cohort 1, where efficacy against clinical malaria did not wane over time, in cohort 2 the efficacy decreases with time. We hypothesize that this reduced duration of protection is a result of the early diagnosis and treatment of infections in cohort 2 participants, preventing sufficient exposure to asexual-stage antigens. On the other hand, the long-term protection against clinical disease observed in cohort 1 may be a consequence of a prolonged exposure to low-dose blood-stage asexual parasitaemia. |