New malaria vaccine provides 100% protection in clinical trial
Scientists have discovered an effective vaccine that offers up to 100 per cent protection from malaria. German researchers at the University of Tübingen in collaboration with the biotech company, Sanaria Incorporated, have demonstrated in a clinical trial that a new vaccine for malaria called Sanaria PfSPZ-CVac has been up to 100 per cent effective when assessed at 10 weeks after last dose of vaccine.
With this discovery, Nigeria can save over 300,000 lives lost to malaria yearly and over N480 billion spent on the treatment and control of the parasite annually. The search for a vaccine has been going on for more than a century. An effective vaccine would make it easier to control malaria; vaccination campaigns could be conducted in severely affected areas to eliminate the pathogen. Such a vaccine could also help to stop the spread of resistance to the treatment, and to better protect travellers.
Details of the research results were published yesterday in the latest edition of the journal Nature. Tübingen University is a public research institution located in the city of Tübingen, Baden-Württemberg. It is one of Germany’s most famous universities in the areas of medicine, natural sciences, and the humanities.
For the trial, Professor Peter Kremsner and Dr. Benjamin Mordmüller of the Institute of Tropical Medicine and the German Centre for Infection Research (DZIF) used malaria parasites provided by Sanaria. The vaccine incorporated fully viable, not weakened or otherwise inactivated, malaria pathogens together with the medication to combat them.
The Tubingen study involved 67 healthy adult test persons, none of whom had previously had malaria. The best immune response was shown in a group of nine test persons who received the highest dose of the vaccine three times at four-week intervals. At the end of the trial, all nine of these individuals had 100 percent protection from the disease.
According to the World Malaria Report 2016 released by the World Health Organisation (WHO), malaria killed 429,000 and infected 212 million people in 2015. It noted that millions of Africans still lack tools to prevent and treat the ailment. Around 90 per cent of those malaria deaths were in Africa. Nearly three-quarters of those who succumb to the disease are children under five.
Malaria parasites are transmitted by the bite of female Anopheles mosquitoes. The Plasmodium falciparum parasite is responsible for most malaria infections and almost all deaths caused by the disease worldwide. Most of the previous vaccines, which have been tried involved the use of individual molecules found in the pathogen.
Prof. Peter Kremsner explained: “The 100 per cent protection was probably caused by specific T-lymphocytes and antibody responses to the parasites in the liver. The researchers analyzed the bodies’ immune reactions and identified protein patterns which will make it possible to further improve malaria vaccines.”
The researchers injected live malaria parasites into the test subjects, at the same time preventing the development of the disease by adding chloroquine — which has been used to treat malaria for many years. This enabled the researchers to exploit the behaviour of the parasites and the properties of chloroquine.
Once the person is infected, the Plasmodium falciparum parasite migrates to the liver to reproduce. During its incubation period there, the human immune system could respond; but at this stage, the pathogen does not make the person sick. On top of that, chloroquine does not take effect in the liver — so it is unable to prevent the parasite from reproducing. Malaria only breaks out when the pathogen leaves the liver, entering the bloodstream and going into the red corpuscles, where it continues to reproduce and spread. As soon as the pathogen enters the bloodstream, however, it can be killed by chloroquine — and the disease cannot break out.
Study leader, Benjamin Mordmueller, said: “By vaccinating with a live, fully active pathogen, it seems clear that we were able to set off a very strong immune response. Additionally, all the data we have so far indicate that what we have here is relatively stable, long-lasting protection.”