RTS,S/ASO1 (RTS.S), trade name Mosquirix, which was endorsed by the World Health Organisation (WHO) on Wednesday (October 6), is the first and, to date only, vaccine shown to have the capability of significantly reducing malaria, and life-threatening severe malaria, in tests on young African children.
The vaccine acts against P. falciparum, the most deadly malaria parasite globally, and the most prevalent in Africa. Among children who received 4 doses in largescale clinical trials, the vaccine was able to prevent approximately 4 in 10 cases of malaria over a 4-year period.
This is the first malaria vaccine that has completed the clinical development process, and received a positive scientific opinion from the European Medicines Agency (EMA).
It is also the first malaria vaccine to be introduced by three national ministries of health through their childhood immunization programmes — more than 800,000 children in Ghana, Kenya, and Malawi have been vaccinated, and are benefiting from the added protection provided by the vaccine as part of a pilot programme.
Other recent clinical evidence shows that strategic delivery of the vaccine just prior to the high malaria transmission season in areas where malaria is highly seasonal can optimize impact and markedly reduce mortality, especially when combined with other recommended malaria control interventions.
The global burden of malaria
Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. It is preventable and curable.
Still, in 2019, there were an estimated 229 million cases of malaria worldwide, and the estimated number of malaria deaths that year stood at 409,000.
Children aged under 5 years are the most vulnerable group affected by malaria; in 2019, they accounted for 67% (274,000) of all malaria deaths worldwide.
In 2019, India had an estimated 5.6 million cases of malaria compared to about 20 million cases in 2000, according to WHO.
How the vaccine can help
WHO’s recommendation is based on the advice of its two global advisory bodies, one for immunization and the other for malaria.
WHO has recommended that in the context of comprehensive malaria control, the RTS,S/AS01 malaria vaccine be used for the prevention of P. falciparum malaria in children living in regions with moderate to high transmission as defined by it.
The malaria vaccine should be provided in a schedule of 4 doses in children from 5 months of age for the reduction of malaria disease and burden.
The next steps for the WHO-recommended malaria vaccine will include funding decisions from the global health community for broader rollout in endemic countries, and country decision-making on whether to adopt the vaccine as part of national malaria control strategies.
A vaccine is a breakthrough addition to the malaria toolkit and can help get malaria control back on track.
Countries that have eliminated malaria
Globally, the elimination net is widening, with more countries moving towards the goal of zero malaria. In 2019, 27 countries reported fewer than 100 indigenous cases of the disease, up from 6 countries in 2000.
Countries that have achieved at least 3 consecutive years of zero indigenous cases of malaria are eligible to apply for the WHO certification of malaria elimination. Over the last two decades, 11 countries have been certified by the WHO Director-General as malaria-free: United Arab Emirates (2007), Morocco (2010), Turkmenistan (2010), Armenia (2011), Sri Lanka (2016), Kyrgyzstan (2016), Paraguay (2018), Uzbekistan (2018), Algeria (2019), Argentina (2019), and El Salvador (2021).
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