Why none of malaria vaccines are effective?

Most of vaccines that have been worked on have aimed to generate antibodies against the parasites

Have you ever thought why none of the vaccines developed for malaria till date has protected against the disease for long? The scientists at QIMR Berghofer Medical Research Institute believe they have found the answer for this.

The discovery potentially paves way for more effective vaccines down the track.

Malaria is caused by parasites that are spread by mosquitoes.

Researchers have been trying to develop a successful vaccine for decades. However, even the most trialled vaccine remained effective even four years after immunisation in a small proportion of people.

Most of the vaccines that have been worked on have aimed to generate antibodies against the parasites.

Dr. Michelle Wykes, the head of the Molecular Immunology Laboratory, along with Joshua Horne-Debets and Deshapriya Karunarathne, found that activating immune cells known as CD8+ T cells was crucial in protecting mice against malaria in the longer term.

"This is the first time there has been evidence to show these immune cells are crucial for protecting against blood stage malaria - which is when symptoms start to show - in the long term. In other words, we've found that antibodies on their own aren't enough to maintain protection against malaria," said Dr. Wykes.

The World Health Organisation (WHO) estimates that malaria caused the deaths of 4,38,000 people and infected 214 million people worldwide in 2015.