The Indian Council of Medical Research (ICMR) has announced a promising candidate vaccine for malaria, which it will now further develop, test and manufacture for commercial purposes in partnership with private companies.Known as AdFalciVax, the vaccine mainly targets two parts of Plasmodium falciparum, a pathogen that is the most common source of malaria in humans. In India, however, the disease is caused by Plasmodium vivax against which AdFalciVax is ineffective.Why is this development significant?Malaria is a parasitic infection transmitted by mosquitoes, typically causing symptoms such as fever, chills, night sweats, nausea, vomiting, and diarrhoea. In some cases, it can lead to severe complications such as seizures, fluid in the lungs, organ damage, and death.Having claimed millions of lives, malaria has been one of the deadliest diseases in human history. Currently, the disease kills about four lakh people annually, according to World Health Organization (WHO) figures.Malaria is most endemic in Africa — Nigeria, Congo, Tanzania, Mozambique, Niger, and Burkina Faso together account for more than half the yearly deaths.The disease is also present in India, although malaria deaths have sharply reduced in the country in recent years. According to the National Vector Borne Disease Control Programme (NVBDCP), reported malaria deaths stood at 1,151in 1995, and came down to only 93 in 2020 and 83 in 2022.Note that these figures are much lower than the numbers provided annually by the WHO. The organisation’s ‘World Malaria Report’ says there were 5,511 deaths due to the disease in India in 2022. This discrepancy is due to WHO providing estimates and NVBDCP providing only the number of confirmed deaths, which may not have been officially reported.Story continues below this adTo combat malaria, scientists have been working to develop a vaccine for decades but with limited success. Recently, two vaccines—RTS,S and R21—were approved for use, but their efficacy, at 75%, is quite low.That’s why the announcement about ICMR’s candidate vaccine has given new hope in the fight against the disease.How does AdFalciVax work?AdFalciVax is a chimeric recombinant vaccine — a type of vaccine that uses different parts of the genes of a pathogen (in this case, Plasmodium) to create target proteins that trigger an immune response after being injected.AdFalciVax uses two types of target proteins to prevent the spread of infection in two different ways.Story continues below this adn It uses the circumsporozoite protein (CSP) to prevent infection in the person who has been immunised. The CSP is produced during the sporozoite stage (when a parasite can infect a new host) and the liver stage (when a parasite enters liver cells, multiplies, and then infects red blood cells) of the parasite.Subhash Singh, project manager for development of the vaccine at the ICMR-Regional Medical Research Centre, Bhubaneswar, told The Indian Express: “Any immune response generated against these stages protects the immunised person from getting the infection.”n The vaccine also uses the Pro6C protein, a fusion of parts of two different proteins — Pfs230 and Pfs48/45 — produced by Plasmodium falciparum. This protein prevents the spread of infection in the community.“The Pro6C protein… stops further spread of the disease by disrupting the lifecycle of the pathogen. It disrupts the development of the parasite in the midgut of a mosquito preventing further transmission,” Singh said.Story continues below this adWhat are the advantages of AdFalciVax?Unlike AdFalciVax, RTS,S and R21 only use the CSP protein, and can prevent infection only in vaccinated persons.Unlike AdFalciVax, RTS,S and R21 vaccines also do not use full-length CSP proteins. This is why the ICMR’s candidate vaccine is “likely to produce a stronger immune response and better protect against infection,” according to Singh.Researchers have found that AdFalciVax provided more than 90% protection against infection in mice. The candidate vaccine has yet to undergo rigorous human trials, and the preliminary results have been obtained only through testing on animals.Studies have also suggested that AdFalciVax produces an immune response that may last longer than that produced by the other two vaccines.Story continues below this adSingh said: “One of the challenges of existing vaccines is that the immune response is short-lived. People need a fifth booster shot even after four primary doses. We do not know how this will work in humans, but preliminary indications show that three doses of the ICMR candidate vaccine produced robust protection against infection in mice for more than three months. This roughly translates to a decade in human life.”AdFalciVax also contains an adjuvant — a substance used in vaccines to boost the body’s immune response against the targeted disease — called alum. Singh says the use of alum is beneficial as it does not pose a risk of causing chronic inflammation, unlike adjuvants such as AS01 and Matrix M, which are used in RTS,S and R21. Alum is also known to be reliable, and has been used in numerous vaccines used in childhood immunisation programs over the years.Another advantage is that alum in AdFalciVax can remain stable at room temperature for at least nine months, according to initial studies. This might make it possible to “transport the vaccines without maintaining the cold chain,” Singh said.What conditions has ICMR set for private players?The ICMR wants to partner with a company that can further develop its candidate vaccine, carry out human clinical trials, and scale up for commercial production.Story continues below this adAlthough the ICMR will share the technology of developing AdFalciVax with the chosen company, it will continue to hold the intellectual property rights. Any intellectual property rights generated during the collaboration will be held jointly by the ICMR and the company. The ICMR will also earn 2% royalty on any sales of the vaccine.Authors from both the company and the ICMR will be credited in any research papers generated, and all data will be jointly owned.