Incidence of Plasmodium falciparum malaria infection in 6-month to 45-year-olds on selected areas of Bioko Island, Equatorial Guinea

Malaria Journal

卷:20

Ummi Abdul Kibondo¹  Maxmillian Mpina¹  Thabit Athuman¹  Salim Abdulla¹  Guillermo A. García²  Kassim Kamaka²  Ally Olotu²  Said Abdallah Jongo²  Ali Mtoro²  Elizabeth Nyakarungu²  Jordan Michael Smith²  Jeremías Nzamio Mba Eyono²  Carlos Cortez Falla²  Ali Hamad Said²  Raul Chuquiyauri²  Martin Eka Ondo Mangue³  Fortunata Lobede Mochomuemue³  Maria-Silvia Angue Lopez³  José Raso³  Juan Carlos Momo Besaha³  Marta Alene Owono³  Beltran Ekua Ntutumu Pasialo³  Escolastica Raquel Mansogo Maye³  Mariano Obiang Obono³  Gertrudis Owono Bidjimi³  Genaro Nsue Nguema Okomo³  Vicente Urbano Nsue Ndong Nchama³  Dolores Mbang Ondo³  L. W. Preston Church⁴  B. Kim Lee Sim⁴  Thomas L. Richie⁴  Peter F. Billingsley⁴  Stephen L. Hoffman⁴  Laurence Lemiale⁴  Claudia Daubenberger⁵  Tobias Schindler⁵  Marcel Tanner⁵ 

[1] Ifakara Health Institute;

[2] Medical Care Development International (MCDI);

[3] Ministry of Health and Social Welfare, Equatorial Guinea (EGMOHSW);

[4] Sanaria Inc.;

[5] Swiss Tropical and Public Health Institute (Swiss TPH);

关键词: Malaria;    Plasmodium falciparum;    Incidence;    PfSPZ Vaccine;    Malabo;    Bioko Island;   

DOI  :  10.1186/s12936-021-03850-8

来源: DOAJ

【 摘 要 】

Abstract Background Extensive malaria control measures have been implemented on Bioko Island, Equatorial Guinea over the past 16 years, reducing parasite prevalence and malaria-related morbidity and mortality, but without achieving elimination. Malaria vaccines offer hope for reducing the burden to zero. Three phase 1/2 studies have been conducted successfully on Bioko Island to evaluate the safety and efficacy of whole Plasmodium falciparum (Pf) sporozoite (SPZ) malaria vaccines. A large, pivotal trial of the safety and efficacy of the radiation-attenuated Sanaria® PfSPZ Vaccine against P. falciparum is planned for 2022. This study assessed the incidence of malaria at the phase 3 study site and characterized the influence of socio-demographic factors on the burden of malaria to guide trial design. Methods A cohort of 240 randomly selected individuals aged 6 months to 45 years from selected areas of North Bioko Province, Bioko Island, was followed for 24 weeks after clearance of parasitaemia. Assessment of clinical presentation consistent with malaria and thick blood smears were performed every 2 weeks. Incidence of first and multiple malaria infections per person-time of follow-up was estimated, compared between age groups, and examined for associated socio-demographic risk factors. Results There were 58 malaria infection episodes observed during the follow up period, including 47 first and 11 repeat infections. The incidence of malaria was 0.25 [95% CI (0.19, 0.32)] and of first malaria was 0.23 [95% CI (0.17, 0.30)] per person per 24 weeks (0.22 in 6–59-month-olds, 0.26 in 5–17-year-olds, 0.20 in 18–45-year-olds). Incidence of first malaria with symptoms was 0.13 [95% CI (0.09, 0.19)] per person per 24 weeks (0.16 in 6–59-month-olds, 0.10 in 5–17-year-olds, 0.11 in 18–45-year-olds). Multivariate assessment showed that study area, gender, malaria positivity at screening, and household socioeconomic status independently predicted the observed incidence of malaria. Conclusion Despite intensive malaria control efforts on Bioko Island, local transmission remains and is spread evenly throughout age groups. These incidence rates indicate moderate malaria transmission which may be sufficient to support future larger trials of PfSPZ Vaccine. The long-term goal is to conduct mass vaccination programmes to halt transmission and eliminate P. falciparum malaria.

【 授权许可】

Unknown