Mosquirix

Subject – Science and Tech

Context – Mosquirix – the first malaria vaccine to get the WHO’s backing

Concept –

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.

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.
Malaria is most endemic in Africa, with Nigeria, Congo, Tanzania, Mozambique, Niger and Burkina Faso together accounting for over half the yearly deaths.
In 2019, India had an estimated 5.6 million cases of malaria compared to about 20 million cases in 2020, according to WHO.

Countries that have eliminated malaria

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).

Reasons for lack of vaccine for so many years –

The difficulty in developing effective malaria vaccines stems largely from the complexity of the malaria-causing parasites’ life cycle, which includes mosquitoes, human liver, and human blood stages, and subsequent antigenic variations of the parasite.
- These parasites are also able to hide inside human cells to avoid being recognised by the immune system, creating further challenges.
Another challenge faced in malaria vaccine development is that the common human malaria-causing parasite, P. falciparum, is not a rodent pathogen.
Because malaria disproportionately affects LMIC (low- and middle-income countries) lacking the robust health infrastructure, the vaccine manufacturers have little incentive for malaria vaccines and continued targeting vaccines for industrialized world markets
Mosquirix itself is the result of more than 30 years of research and development, and yet has only modest efficacy.

To know more about Malaria, please click here.

To know about Antimalarial Drug Resistance, please click here.

To know about the efforts to end malaria, please click here.