New hope for malaria vaccine: the science, challenges, opportunity

Source: The post is based on the article “New hope for malaria vaccine: the science, challenges, opportunity” published in the Indian Express on 7th November 2022. 

Syllabus: GS 3 – Developments and their applications and effects in everyday life.

Relevance: About Malaria vaccines and India’s vaccine research.

News: Malaria kills nearly 600,000 people every year, the majority of whom are children under the age of five in sub-Saharan Africa. The need to develop an effective vaccine against the disease has long been a top priority.

What are the promising breakthroughs in Malaria vaccines?

RTS,S/ASO1 (RTS.S): Its trade name “Mosquirix” was endorsed by the World Health Organisation (WHO) recently.

Read here: What is Mosquirix, the first malaria vaccine to get the WHO’s backing?

Although RTS,S/AS01 has modest efficacy and reduces severe malaria cases by only about 30% after four doses given to children under age 5, it still provides significant public health benefits and could save thousands of lives every year.

However, RTS,S/AS01 fails to meet the WHO’s own benchmark for malaria vaccine efficacy of 75 per cent set in 2015.

R21/Matrix M: It is a modified version of Mosquirix and has been developed by researchers at the University of Oxford.

Read here: R21/Matrix M: a new malaria vaccine

This vaccine demonstrated an efficacy of 77% in phase 1 and 2 trials among 450 children in Burkina Faso. In early September 2022, a booster dose of R21/Matrix-M showed a high efficacy of 80%.

Phase 3 trials of R21 are already underway in four African countries.

What are the commonalities of both Malaria vaccines?

RTS,S and R21 both contain the same part of a major protein that is found on the surface of the liver stage parasite, called sporozoite.

Both contain hepatitis B virus surface antigen (HBsAg), a protein that has the ability to self-assemble and that helps in the formation of virus-like particles of the CSP antigen fused with it.

What are the differences between both Malaria vaccines?

The amount of the HBsAg: RTS,S has about 20 per cent of the fusion protein, with the remaining 80 per cent made up of HBsAg antigen, produced separately.

R21, on the other hand, is made up entirely of the CSP fusion protein moieties, resulting in much higher proportion of CSP antigen displayed on the virus-like particle surface, which significantly raises its exposure to the immune system of the host.

Read more: Malaria Vaccine and India’s Malaria burden – Explained, pointwise
Why has India not been more successful in developing the Malaria vaccine and other vaccines?

Basic malaria research in India has been robust and there are well established malaria research and control centres across the country. Despite that, India is not able to develop vaccines because,

a) There is a major gap is in the establishment of safe and scientifically robust control human infection models in India for diseases like malaria or influenza, b) Absent of Controlled Human Malaria Infection (CHMI) model: Scientists have carried out phase 1 safety trials of two experimental blood-stage malaria vaccines developed and produced in the country. But further development of these vaccines has been a challenge in the absence of the CHMI model in India.

What needs to be done to promote vaccine research in India?

The government should provide long-term continuous funding. Further, regulatory and logistic processes need to be better coordinated to assist scientists in the development of novel vaccines against infectious diseases.

India should capitalise on the highly successful and deeply committed vaccine-producing biopharma industry and a strong scientific base. This will make India in leading the world in developing and producing vaccines.

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