Malaria elimination: Vaccines should be tested on larger groups of volunteers

January 12, 2017

To find an effective vaccine against malaria it is crucial to test candidate vaccines on larger groups of people than previously thought - according to a new study published in PLOS Computational Biology. The researchers from Erasmus MC Rotterdam and Radboud University Medical Center Nijmegen developed a mathematical model to determine the minimum number of people required for a good vaccine trial.

Malaria continues to be a major public health challenge; killing 438,000 people every year and being the leading cause of death in children worldwide. Before a malaria vaccine may be tested on a large group of people, there must be sufficient evidence for a relevant and beneficial effect, with minimal risks and side effects. Few candidate vaccines meet these requirements.

Over the past ten years, only 40 of the many candidate vaccines were actually clinically tested on humans. Only one vaccine (RTS,S vaccine) appears to be promising, which means that children are 45.7 percent protected from malaria for 18 months after vaccination. "By vaccinating a larger group of people in clinical studies with a candidate vaccine in the early testing phase, we increase the likelihood of finding a greater number of promising vaccines, and therefore also accelerate the discovery of an effective vaccine against this disease", says Luc Coffeng, researcher at Erasmus MC's Department of Public Health.

One of the first steps in testing candidate vaccines on humans occurs in CHMI (controlled human malaria infection) studies. In these studies, healthy volunteers are infected with malaria in a highly controlled environment to evaluate a possible protective effect of the candidate vaccine. "It is important that enough volunteers participate so as to be able to draw accurate conclusions. On the other hand, we want to keep the groups as small as possible to avoid exposing people to malaria unnecessarily", says Robert Sauerwein, Professor of Medical Parasitology at Radboud University Medical Center.

In this study the researchers show that the search for an effective vaccine can be accelerated if the group of clinical trial volunteers participating in CHMI studies is enlarged. Their mathematical model is able to determine the ideal size of the group of volunteers and it also highlights the drastic impact of the loss of any study subjects - This can occur as a result of experimental failure and can have a negative impact on trial power. Coffeng: "We hope that this model will contribute to more effective studies and ultimately to eliminating malaria."
-end-
This text is based on a press release provided by the authors.

In your coverage please use this URL to provide access to the freely available article in PLOS Computational Biology: http://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005255

Citation: Coffeng LE, Hermsen CC, Sauerwein RW, de Vlas SJ (2017) The Power of Malaria Vaccine Trials Using Controlled Human Malaria Infection. PLoS Comput Biol 13(1): e1005255. doi:10.1371/journal.pcbi.1005255

Funding: The CHMI experiments from studies 0004-00900 (subjects marked EHMI-2), 0011±0262 (EHMI-3), 2001/203 (EHMI-4), and 2002/170 (EHMI-5) were financially supported by the European Commission Fifth Framework Programme, contract numbers QLK2-CT-1999-01293 and QLK2-CT-2002-01197. Studies NCT00442377 and NCT00757887 (EHMI-8A, B) were supported by the Dioraphte Foundation (http://www.dioraphte.nl). Study NCT00509158 (LSA3) was sponsored by Dictagene SA, Epalinges, Switzerland (no longer in existence). Study NCT01002833 (TIP-1) was supported by Top Institute Pharma (grant T4-102) and the European Malaria Vaccine Development Association (http://www.emvda.org). Last, study NCT01236612 (ZonMw) was funded by The Netherlands Organisation for Health Research and Development (ZonMw, project 95110086) and the Dioraphte Foundation (project 12010100). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

PLOS

Related Malaria Articles from Brightsurf:

Clocking in with malaria parasites
Discovery of a malaria parasite's internal clock could lead to new treatment strategies.

Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the UmeƄ University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.

Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.

New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.

Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.

Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.

Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.

Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.

Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.

The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.

Read More: Malaria News and Malaria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.