Using two experimental anti-malarial vaccines, which work in different ways, can greatly reduce the number of malaria infections in animal studies.
Experimental vaccines, which independently achieve 48% and 68% reductions in malaria cases, can achieve 91% reduction when combined.
Presently, each vaccine is at a different stage of human trials, and there have not been efforts to combine them. However, a team led by Imperial College London have now tested the effectiveness when using the two types of vaccine together.
Reaching a potential 91% reduction in cases would have a huge impact on public health because the vaccines could be effective in areas where malaria is more prevalent.Dr Andrew Blagborough
The study, published today in the journal eLife, used genetically altered mouse parasites that express proteins expressed on the human version of the malaria parasite. The research was funded by the PATH’s Malaria Vaccine Initiative and the Medical Research Council (MRC), including researchers at Imperial’s MRC Centre for Outbreak Analysis and Modelling.
Lead researcher Dr Andrew Blagborough, from the Department of Life Sciences at Imperial, said: “This is the first direct evidence than combining vaccines of different types significantly improves their efficacy in terms of reducing malarial burden.
“Reaching a potential 91% reduction in cases would have a huge impact on public health because the vaccines could be effective in areas where malaria is more prevalent.”
Two types of vaccines
Malaria is caused by a group of parasites that have a complex life cycle, spending time in the mosquito midgut and salivary glands, in the human liver, and circulating in human blood, where they cause the disease.
The team tested two types of vaccines: those that prevent mosquitoes from transferring the parasites, called transmission-blocking vaccines (TBVs), and those that prevent the parasite from infecting the liver, termed pre-erythrocytic vaccines (PEVs).
RTS,S is the world’s first PEV malaria vaccine that has been shown to provide partial protection against malaria in young children by blocking infection of the liver. However, its maximum efficacy is under 50% (i.e. it reduces cases by around 50%).
There are currently several types of transmission-blocking vaccines in early trials, which are thought to reduce the number of parasites in the mosquito salivary glands. Their efficacy typically ranges from around 50-95%.
It has been assumed that combining these vaccines would increase their efficacy, but it has never been tested until now. The team found that when a partially effective PEV was combined with the most effective transmission-blocking vaccine, the efficacy was around 91%.
The team also found that combining any of the two types of vaccines improved efficacy of the mixture more than might be expected from the single efficacy of each vaccine separately.
Working towards elimination
Dr Morven Roberts, Programme Manager for parasites and neglected tropical diseases at the MRC, said: “While these findings are in the preliminary stages, they’re valuable as they shed light on optimising strategies for preventing malaria. Learning that combining vaccines can dramatically boost efficacy in mice provides another potential tactic for controlling this disease. This is timely research as global health officials work towards WHO targets to eliminate malaria by 2030.”
The team will next study how combined vaccines could work in more complex situations. Dr Blagborough said: “In the real world, the vaccine coverage we can achieve– how many people we can give it to – is important, as are the local levels of transmission, and how prevalent malaria currently is in that area.
“We plan to use a combination of rodent experiments and computer modelling to help us estimate effectiveness requirements for future vaccines.”
The efficacy of current lead malaria vaccines is known to reduce over time after vaccines are administered, so the team will also investigate how combined vaccines perform in the long term.
The Latest on: Malaria
via Google News
The Latest on: Malaria
Jigawa govt to distribute 3.5m nets to prevent malaria
on July 11, 2018 at 7:17 am
The Jigawa government says it will distribute 3.5million Long Life Insecticidal Nets to its people during this season to check malaria scourge. Dr Abba Zakari, the state Commissioner for Health, said ... […]
Fewer malaria nets, lower costs, more protection
on July 10, 2018 at 8:44 am
Insecticide-treated bed nets—a crucial part of malaria protection throughout sub-Saharan Africa and regions of Asia—have long been distributed to people who need them through mass campaigns conducted ... […]
Why some people test positive for malaria after successful anti-malarial treatment
on July 10, 2018 at 7:47 am
Treating patients with malaria first requires a confirmed diagnosis. It has recently come to light that not all diagnosis tests are equal, and some tests, including rapid diagnostic tests (RDTs), can ... […]
Certain antibodies against a carbohydrate could protect against malaria
on July 10, 2018 at 2:29 am
Certain type of antibodies against α-Gal- a carbohydrate expressed by many organisms including the malaria parasite- could protect against malaria, according to a new study led by ISGlobal, an institu... […]
Atomic imaging exposes how malaria invades our blood cells
on July 9, 2018 at 5:33 pm
New research reveals, at an atomic level, how a major form of malaria, P. vivax, invades our red blood cells. The mosquito-borne malaria parasite is an ancient killer, predating the emergence of human... […]
A breakthrough for malaria elimination starts in the Americas
on July 9, 2018 at 1:30 pm
The views expressed by contributors are their own and not the view of The Hill A new global push in the fight against malaria began last month when Paraguay became the first country in the Americas to ... […]
Certain antibodies against a sugar are associated with malaria protection
on July 9, 2018 at 11:08 am
Certain type of antibodies against alpha-Gal- a carbohydrate expressed by many organisms including the malaria parasite- could protect against malaria, according to a new study. The resultsindicate th... […]
In a Rare Success, Paraguay Conquers Malaria
on July 9, 2018 at 2:02 am
A malaria specialist in Las Claritas, Venezuela, analyzing blood samples of patients who showed symptoms of infection. While Paraguay has recently eliminated the disease, other countries in the Americ... […]
A promising new tool to measure antibodies against malaria
on July 4, 2018 at 2:58 am
A multipipette is used for handling multiple samples when performing quantitative suspension arrays. Credit: Pau Fabregat Antibodies against multiple Plasmodium falciparum proteins (or antigens) can b... […]
via Bing News