During the past 15 years malaria control programs using insecticide impregnated bednets, indoor spraying of residual insecticides, and case management have significantly reduced the morbidity and mortality caused by malaria.  However, in 2016, there were still 216 million cases of malaria and an estimated 445,000 deaths worldwide, with over 90% occurring in Sub-Saharan Africa. Recognizing that the current toolkit is insufficient on its own to eliminate malaria, and that controlling malaria is a constant public health and political battle, Sanaria Inc. has taken important steps towards developing a vaccine that prevents the malaria infection.

PfSPZ Vaccine is one of a portfolio of unique vaccine candidates composed of Plasmodium falciparum (Pf) sporozoites (SPZ), sufficiently weakened such that they can invade the human liver, but not continue to the disease-causing blood stage infection.  The PfSPZ Vaccine induces powerful cellular immune responses in the liver that prevent future malaria infections (see Table 1), and thereby prevent disease and further transmission to mosquitoes.  Sanaria’s PfSPZ Vaccine manufacture and clinical testing will soon be at phase three compliance: the last step before licensure, and ability for distribution to general populations.

Moving towards licensure and importantly, to provide evidence that the vaccine is safe and tolerable in African populations, Sanaria is working  with the Government of Equatorial Guinea (EG), which along with three private funders, Marathon Oil Corporation, Noble Energy and Atlantic Methanol Production Company, are committed to furthering the development of PfSPZ Vaccine. The team will conduct a phase three trial, then a randomized cluster study to show public health utility and immunity at the community level, followed by an ambitious demonstration project for Pf elimination on Bioko Island.

In 2013 the Equatorial Guinea Malaria Vaccine Initiative (EGMVI) was conceived, engaging two additional partners –  the Ifakara Health Institute (IHI, Tanzania), and the Swiss Tropical and Public Health Institute (Swiss TPH). To date, the EGMVI has conducted two safety trials incorporating 168 Equatoguinean volunteers from ages six months to 65 years of age, which have shown that there are no adverse reactions to the vaccine and tolerability is very high.

The EGMVI is targeting Bioko Island, with a population of nearly 250,000, to be the first location in sub-Saharan Africa to eliminate malaria using a vaccine to complement accepted malaria prevention and control practices.  If successful, this project will demonstrate that it is possible to eliminate malaria from a highly endemic area.

This demonstration project will build on a 15-year, internationally recognized malaria control program on Bioko Island called the Bioko Island Malaria Control Project (BIMCP) implemented by Medical Care Development International (MCDI)  This long-standing public private partnership between the Government of Equatorial Guinea, Marathon Oil, Noble Energy, Atlantic Methanol Production Company, GePetrol, and Sonagas, has reduced malaria prevalence by 76% in 2-14 year olds, infant mortality by 85%, and infected mosquito bites from an ~1,000 to just eight per year.

The EGMVI has trained a cohort of national clinicians and nurses, laboratory technicians, data managers, and community based recruitment and volunteer coordinators, who will eventually form the nucleus of an EG national public health institute.

The South-South link established between EG and Tanzania has resulted in dialogues between the Equatoguinean and Tanzanian Ministries of Health to explore future collaborations between the two countries. Through the EGMVI, the Equatoguinean Ministry of Health and Social Welfare has participated in the WHO’s African Vaccine Regulatory Forum. Future efforts will see EG participate in regional pan African initiatives. Further, It has helped to raise the profile of  EG researchers and their vaccine research, through multiple presentations at the Multilateral Initiative on Malaria meeting in Dakar in April 2018.

But it is the planned integration of current control methods with PfSPZ Vaccine and the integration of many seemingly disparate partners that offers a truly unique approach to eliminate malaria from Bioko Island. If successful, the impact could include at least a 1% increase in GDP of the region, and the prevention of hundreds of thousands of deaths in Africa and beyond.

Table 1.  Summary of clinical studies with PfSPZ Vaccine.  The vaccine has been tested in several studies (some ongoing) that have demonstrated its strong efficacy by controlled human malaria infection (CHMI) or by natural exposure.  CHMI involves inoculating vaccinated individuals with malaria parasites by mosquito bite or injection, then monitoring to see if a blood stage infection develops.  The inoculated parasites can be of the same (homologous) or different (heterologous) strain of parasite as that used to make the vaccine.

Location of Study	Test method	Efficacy	Interpretation
USA, Tanzania, Equatorial Guinea	CHMI	>90% protection against homologous Pf at 3 weeks	Short term, extremely high protection against homologous strain of malaria is possible with 3- and 5-dose regimens
		75%-80% protection against heterologous Pf 3 weeks	Short term, high protection against heterologous strain of malaria is possible with 4- and 5-dose regimens
		55%-65% protection against homologous Pf at 5, 6 and 14 months	Medium and long term protection against homologous strain of malaria is possible with 3-, 4- and 5-dose regimens
		54% protection against heterologous Pf at 8 months	Long term heterologous protection against infection
Mali	Natural Exposure	51%-52% (time to event analysis) and 24%-29% (proportional analysis) for 6 months	Long term protection against natural, genetically heterogeneous Pf populations is possible in an area of intense transmission with 3- or 5-dose regimens

 

“Hope for Bioko” – Marathon Oil and our partners in the Bioko Island Malaria Control Project commemorated the 10th anniversary of the life-saving project in 2014. Marathon Oil led the formation of the unique public-private partnership that supports the project after identifying rampant malaria as the largest social risk to the Company and the community in Equatorial Guinea. For more information and to download the commemorative book, visit: http://www.marathonoil.com