New York, An experimental new malaria vaccine is offering potentially long-lasting immunity against the persistent parasite that sickens hundreds of millions of people each year, a study suggests.
Most vaccines are designed to encourage the human body to respond to invading, disease-causing pathogens by creating antibodies that disable those pathogens.
However, the new vaccine takes a different approach by using a weakened form of a common herpes virus – cytomegalovirus, or CMV – that infects most people without causing the disease.
This new vaccine reduced the malaria-causing parasite’s release from the liver and into the blood of infected rhesus macaques by 75 to 80 per cent, reported the paper published in the journal PLOS ONE.
“The problem with most vaccines is that their effectiveness is often short-lived,” said lead author Klaus Fruh, professor at the Oregon Health and Science University in the US.
“Our cytomegalovirus-based vaccine platform can create and keep immunity for life. With further research and development, it could offer a lifetime of protection against malaria,” Fruh added.
Malaria is a serious and sometimes fatal disease caused by Plasmodium parasites, which are spread to humans through mosquito bites.
It can cause high fevers, shaking chills, flu-like illness and, in the worst cases, death.
Worldwide, 216 million people were infected with malaria in 2016, leading to 445,000 deaths.
Fruh and his team weaved tiny bits of their target pathogen into CMV, which is already being used in vaccines being developed to battle HIV and tuberculosis.
Those who receive the resulting, re-engineered CMV vaccine produce memory T-cells that can search for and destroy pathogen-infected cells.
The team developed two different versions of their CMV-based malaria vaccine while using four different proteins made by the Plasmodium parasite.
The resulting vaccines delayed the parasite’s appearance in the blood of 16 infected and vaccinated rhesus macaques by eliminating between 75 and 80 per cent of parasites from the liver.
A year later, the vaccinated non-human primates still had immunity against malaria, while eight control animals that were not vaccinated did not.
The CMV vaccine platform has been licensed by San Francisco-based Vir Biotechnology, which plans to lead a human clinical trial for a CMV-based HIV vaccine in 2019.