Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children
<h4>Background</h4> <p>The RTS,S/AS01 malaria vaccine candidate is being evaluated for implementation.</p> <h4>Methods</h4> <p>We conducted 7 years follow-up of children who were randomized at age 5 to 17 months to receive three doses of either the RTS,S/AS...
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| Format: | Journal article |
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Massachusetts Medical Society
2016
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| _version_ | 1826288944304619520 |
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| author | Olotu, A Fegan, G Juliana, W Nyangweso, G Leach, A Marc, L Kaslow, D Njuguna, P Kevin, M Bejon, P |
| author_facet | Olotu, A Fegan, G Juliana, W Nyangweso, G Leach, A Marc, L Kaslow, D Njuguna, P Kevin, M Bejon, P |
| author_sort | Olotu, A |
| collection | OXFORD |
| description | <h4>Background</h4> <p>The RTS,S/AS01 malaria vaccine candidate is being evaluated for implementation.</p> <h4>Methods</h4> <p>We conducted 7 years follow-up of children who were randomized at age 5 to 17 months to receive three doses of either the RTS,S/AS01 vaccine or control vaccine (rabies). The endpoint was clinical malaria (temperature ≥37.5°C and infection with Plasmodium falciparum of ≥2500 parasites per µl). Each child’s malaria exposure was estimated using the prevalence of malaria among residents within a 2km radius of their homestead. Vaccine efficacy was defined as 1 minus the hazard ratio (HR) or incidence rate ratios (IRR) of the RTS,S/AS01 vaccinated versus rabies vaccinated groups. </p> <h4>Results</h4> <p>We identified 1002 clinical malaria episodes among 223 children randomized to RTS,S/AS01 and 992 clinical malaria episodes among 224 children randomized to control vaccination over seven years follow-up. Intention-to-treat vaccine efficacy (VE) was 4.4% (95%CI: -17 to 21.9, p value=0.67) and per-protocol VE was 7.0% (95%CI -14.5 to 24.6%, p=0.5) by negative binomial regression. VE waned over time (p=0.006 for the interaction between vaccination and time), including negative efficacy during the fifth year among children at higher malaria parasite exposure (-43.5%, 95%CI: -100.3 to -2.8, p value=0.033 by intention-to-treat and -56.8%, 95%CI -118.7 to -12.3, p=0.008 per-protocol). </p> <h4>Conclusion</h4> <p>A 3-dose vaccination with RTS,S/AS01 is initially protective against clinical malaria, but this is offset by rebound in later years in areas with higher malaria parasite exposure. Further data are needed on longer-term outcomes following four-dose vaccinations. </p> |
| first_indexed | 2024-03-07T02:21:22Z |
| format | Journal article |
| id | oxford-uuid:a4095cf4-29e2-4d9e-a26b-5f273a9d85db |
| institution | University of Oxford |
| last_indexed | 2024-03-07T02:21:22Z |
| publishDate | 2016 |
| publisher | Massachusetts Medical Society |
| record_format | dspace |
| spelling | oxford-uuid:a4095cf4-29e2-4d9e-a26b-5f273a9d85db2022-03-27T02:31:10ZSeven year efficacy of RTS,S/AS01 malaria vaccine in young African childrenJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a4095cf4-29e2-4d9e-a26b-5f273a9d85dbSymplectic Elements at OxfordMassachusetts Medical Society2016Olotu, AFegan, GJuliana, WNyangweso, GLeach, AMarc, LKaslow, DNjuguna, PKevin, MBejon, P <h4>Background</h4> <p>The RTS,S/AS01 malaria vaccine candidate is being evaluated for implementation.</p> <h4>Methods</h4> <p>We conducted 7 years follow-up of children who were randomized at age 5 to 17 months to receive three doses of either the RTS,S/AS01 vaccine or control vaccine (rabies). The endpoint was clinical malaria (temperature ≥37.5°C and infection with Plasmodium falciparum of ≥2500 parasites per µl). Each child’s malaria exposure was estimated using the prevalence of malaria among residents within a 2km radius of their homestead. Vaccine efficacy was defined as 1 minus the hazard ratio (HR) or incidence rate ratios (IRR) of the RTS,S/AS01 vaccinated versus rabies vaccinated groups. </p> <h4>Results</h4> <p>We identified 1002 clinical malaria episodes among 223 children randomized to RTS,S/AS01 and 992 clinical malaria episodes among 224 children randomized to control vaccination over seven years follow-up. Intention-to-treat vaccine efficacy (VE) was 4.4% (95%CI: -17 to 21.9, p value=0.67) and per-protocol VE was 7.0% (95%CI -14.5 to 24.6%, p=0.5) by negative binomial regression. VE waned over time (p=0.006 for the interaction between vaccination and time), including negative efficacy during the fifth year among children at higher malaria parasite exposure (-43.5%, 95%CI: -100.3 to -2.8, p value=0.033 by intention-to-treat and -56.8%, 95%CI -118.7 to -12.3, p=0.008 per-protocol). </p> <h4>Conclusion</h4> <p>A 3-dose vaccination with RTS,S/AS01 is initially protective against clinical malaria, but this is offset by rebound in later years in areas with higher malaria parasite exposure. Further data are needed on longer-term outcomes following four-dose vaccinations. </p> |
| spellingShingle | Olotu, A Fegan, G Juliana, W Nyangweso, G Leach, A Marc, L Kaslow, D Njuguna, P Kevin, M Bejon, P Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children |
| title | Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children |
| title_full | Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children |
| title_fullStr | Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children |
| title_full_unstemmed | Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children |
| title_short | Seven year efficacy of RTS,S/AS01 malaria vaccine in young African children |
| title_sort | seven year efficacy of rts s as01 malaria vaccine in young african children |
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