1
|
Bell GJ, Gyaase S, Goel V, Adu B, Mensah B, Essone P, Dosoo D, Osei M, Niare K, Wiru K, Brandt K, Emch M, Ghansah A, Asante KP, Mvalo T, Agnandji ST, Juliano JJ, Bailey JA. Background malaria incidence and parasitemia during the three-dose RTS,S/AS01 vaccination series do not reduce magnitude of antibody response nor efficacy against the first case of malaria. BMC Infect Dis 2023; 23:716. [PMID: 37872492 PMCID: PMC10594884 DOI: 10.1186/s12879-023-08699-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/11/2023] [Indexed: 10/25/2023] Open
Abstract
BACKGROUND RTS,S/AS01 has been recommended by WHO for widespread implementation in medium to high malaria transmission settings. Previous analyses have noted lower vaccine efficacies in higher transmission settings, possibly due to the more rapid development of naturally acquired immunity in the control group. METHODS To investigate a reduced immune response to vaccination as a potential mechanism behind lower efficacy in high transmission areas, we examine initial vaccine antibody (anti-CSP IgG) response and vaccine efficacy against the first case of malaria (to exclude the effect of naturally acquired immunity) using data from three study areas (Kintampo, Ghana; Lilongwe, Malawi; Lambaréné, Gabon) from the 2009-2014 phase III trial (NCT00866619). Our key exposures are parasitemia during the vaccination series and background malaria incidence. We calculate vaccine efficacy (one minus hazard ratio) using a cox-proportional hazards model and allowing for the time-varying effect of RTS,S/AS01. RESULTS We find that antibody responses to the primary three-dose vaccination series were higher in Ghana than in Malawi and Gabon, but that neither antibody levels nor vaccine efficacy against the first case of malaria varied by background incidence or parasitemia during the primary vaccination series. CONCLUSIONS We find that vaccine efficacy is unrelated to infections during vaccination. Contributing to a conflicting literature, our results suggest that vaccine efficacy is also unrelated to infections before vaccination, meaning that control-group immunity is likely a major reason for lower efficacy in high transmission settings, not reduced immune responses to RTS,S/AS01. This may be reassuring for implementation in high transmission settings, though further studies are needed.
Collapse
Affiliation(s)
- Griffin J Bell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA.
| | | | - Varun Goel
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Bright Adu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Benedicta Mensah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Paulin Essone
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - David Dosoo
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Musah Osei
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Karamoko Niare
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, 02912, USA
| | - Kenneth Wiru
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Katerina Brandt
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA
- Carolina Population Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Anita Ghansah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | - Tisungane Mvalo
- University of North Carolina Project, Lilongwe, Malawi
- Department of Pediatrics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Jonathan J Juliano
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, 27599, USA
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, 02912, USA
| |
Collapse
|
2
|
Bell GJ, Gyaase S, Goel V, Adu B, Mensah B, Essone P, Dosoo D, Osei M, Niare K, Wiru K, Brandt K, Emch M, Ghansah A, Asante KP, Mvalo T, Agnandji ST, Juliano JJ, Bailey JA. Malaria Transmission Intensity and Parasitemia during the Three-Dose RTS,S/AS01 Vaccination Series do not Reduce Magnitude of Antibody Response nor Efficacy Against the First Case of Malaria. Res Sq 2023:rs.3.rs-2960373. [PMID: 37292711 PMCID: PMC10246269 DOI: 10.21203/rs.3.rs-2960373/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background RTS,S/AS01 has been recommended by WHO for widespread implementation in medium to high malaria transmission settings. Previous analyses have noted lower vaccine efficacies in higher transmission settings, possibly due to the more rapid development of naturally acquired immunity in the control group. Methods To investigate a reduced immune response to vaccination as a potential mechanism behind lower efficacy in high transmission areas, we examine initial vaccine antibody (anti-CSP IgG) response and vaccine efficacy against the first case of malaria to exclude the delayed malaria effect using data from three study areas (Kintampo, Ghana; Lilongwe, Malawi; Lambaréné, Gabon) from the 2009-2014 phase III trial (NCT00866619). Our key exposures are parasitemia during the vaccination series and malaria transmission intensity. We calculate vaccine efficacy (one minus hazard ratio) using a cox-proportional hazards model and allowing for the time-varying effect of RTS,S/AS01. Results We find that antibody responses to the primary three-dose vaccination series were higher in Ghana than in Malawi and Gabon, but that neither antibody levels nor vaccine efficacy against the first case of malaria varied by transmission intensity or parasitemia during the primary vaccination series. Conclusions We find that vaccine efficacy is unrelated to infections during vaccination. Contributing to a conflicting literature, our results suggest that vaccine efficacy is also unrelated to infections before vaccination, meaning that delayed malaria is likely the main reason for lower efficacy in high transmission settings, not reduced immune responses. This may be reassuring for implementation in high transmission settings, though further studies are needed.
Collapse
|
3
|
Bell GJ, Goel V, Essone P, Dosoo D, Adu B, Mensah BA, Gyaase S, Wiru K, Mougeni F, Osei M, Minsoko P, Sinai C, Niaré K, Juliano JJ, Hudgens M, Ghansah A, Kamthunzi P, Mvalo T, Agnandji ST, Bailey JA, Asante KP, Emch M. Malaria Transmission Intensity Likely Modifies RTS, S/AS01 Efficacy Due to a Rebound Effect in Ghana, Malawi, and Gabon. J Infect Dis 2022; 226:1646-1656. [PMID: 35899811 PMCID: PMC10205900 DOI: 10.1093/infdis/jiac322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/26/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND RTS,S/AS01 is the first malaria vaccine to be approved and recommended for widespread implementation by the World Health Organization (WHO). Trials reported lower vaccine efficacies in higher-incidence sites, potentially due to a "rebound" in malaria cases in vaccinated children. When naturally acquired protection in the control group rises and vaccine protection in the vaccinated wanes concurrently, malaria incidence can become greater in the vaccinated than in the control group, resulting in negative vaccine efficacies. METHODS Using data from the 2009-2014 phase III trial (NCT00866619) in Lilongwe, Malawi; Kintampo, Ghana; and Lambaréné, Gabon, we evaluate this hypothesis by estimating malaria incidence in each vaccine group over time and in varying transmission settings. After estimating transmission intensities using ecological variables, we fit models with 3-way interactions between vaccination, time, and transmission intensity. RESULTS Over time, incidence decreased in the control group and increased in the vaccine group. Three-dose efficacy in the lowest-transmission-intensity group (0.25 cases per person-year [CPPY]) decreased from 88.2% to 15.0% over 4.5 years, compared with 81.6% to -27.7% in the highest-transmission-intensity group (3 CPPY). CONCLUSIONS These findings suggest that interventions, including the fourth RTS,S dose, that protect vaccinated individuals during the potential rebound period should be implemented for high-transmission settings.
Collapse
Affiliation(s)
- Griffin J Bell
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Varun Goel
- Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Paulin Essone
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - David Dosoo
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Bright Adu
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | | | - Kenneth Wiru
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Fabrice Mougeni
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Musah Osei
- Kintampo Health Research Centre, Kintampo, Ghana
| | - Pamela Minsoko
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - Cyrus Sinai
- Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Karamoko Niaré
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, USA
| | - Jonathan J Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Michael Hudgens
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Anita Ghansah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | | | | | - Selidji Todagbe Agnandji
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island, USA
| | | | - Michael Emch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
- Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina, USA
| |
Collapse
|
4
|
Kalsdorf B, Essone P, Chegou NN, Loxton A, Kriel D, Preyer R, Ernst M, Lange C, Walzl G. Differenzierung zwischen latenter Infektion mit M. tuberculosis und aktiver Tuberkulose. Pneumologie 2012. [DOI: 10.1055/s-0032-1302531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|