What went into making of malaria vaccine’s new version and why it matters

The vaccine targets the liver stage protein of the parasite’s life cycle.

A candidate of a malaria vaccine has shown promise in clinical trials of phase 2b, with high efficacy at 77 per cent. The trial results were recently published in preprints with The Lancet. R21/Matrix M- the new vaccine candidate, is a modified version of RTS, S – another candidate against malaria by GlaxoSmithKline, Walter Reed Institute of Research, Bill and Melinda Gates Foundation with the PATH Malaria Vaccine Initiative, that has been in development for more than 30 years now. This is designed with an aim to stop the malaria parasite- Plasmodium falciparum from entering the liver and preventing the subsequent deadly blood stages. The vaccine targets the liver stage protein of the parasite’s life cycle, according to an IE report.

According to Dr V S Chauhan, a Rhodes scholar working in the fields of genetic engineering and biotechnology, RTS,S is the first and the only vaccine, to date, to reduce malaria in children but is not highly efficacious. He said that the vaccine’s efficacy is so low that it is not given widely. Research on this is going on and the new vaccine is a modified version of the previous one. Also, it has to undergo phase 3 trials yet, Dr Chauhan stated, who is known for his contribution to a recombinant vaccine’s development for malaria.

New version of vaccine

The new version- R21/Matrix M has been developed at the University of Oxford, the same place where the AstraZeneca vaccine was developed for Covid-19 infection. Scientists have been working on this version of the vaccine for almost six to seven years now. According to study author Adrian Hill, Jenner Institute’s director and Oxford University’s professor of vaccinology, the vaccine was the first to reach the World Health Organization’s goal of the efficacy of at least 75 per cent. The production of this vaccine was done in the Serum Institute of India.

Vaccine trial

Findings were reported by Oxford researchers and partners on R21 over 12 months of follow-up of participants. The trial of phase 2b in as many as 450 children in Burkina Faso found the vaccine to be safe with an efficacy of 77 per cent over this period. The vaccine underwent trial in 2014-2015. The two-dose trial of the vaccine was divided into a high dose trial and low dose trial, and both showed an efficacy of 77 per cent.

Next step

Recruitment has been started by researchers working together with SII and US vaccine maker Novavax for a phase 3 trial to assess large-scale safety as well as efficacy in 4,800 children, aged 5 months to 36 months across four African countries. SII said to deliver over 200 million vaccine doses as soon as it gets regulators’ nod.

Why the vaccine matters

An estimated 229 million malaria cases and 409 000 malaria-related deaths were recorded in 87 countries in the year 2019. Children below five years of age in sub-Saharan Africa accounted for around two-thirds of global deaths. Between the period 2000 and 2020, 24 nations reported zero indigenous malaria cases for three or more years. This is the benchmark for the WHO certification of a malaria-free nation. Around the world, a total of 39 countries have achieved the milestone. According to WHO, India saw an estimated 5.6 million malaria cases in the year 2019 compared to around 20 million malaria cases in 2020. Last year’s case estimates (regional, country and global level) will be published later this year.

COVID-19 challenge

In 2020, the COVID-19 outbreak emerged as a serious challenge to global malaria responses. As per the results of a new survey by WHO, during the first quarter of 2021, nearly one-third of countries reported disruptions in prevention, diagnosis and treatment services for malaria. Lockdowns and restrictions on people and goods’ movement have led to delays in many countries in the delivery of indoor insecticide spraying campaigns or insecticide-treated mosquito nets. Also, diagnosis along with treatment services were interrupted for Malaria as several people were unable or unwilling to seek care in health facilities. On April 25- World Malaria Day, the World Health Organization called on all people living in countries that are malaria-affected to “beat the fear”.