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All you need to know about the first WHO-approved malaria vaccine, RTS,S

Emeh Joy
By Emeh Joy

Basic Medical Scientist, Freelance Health Writer, Lifestyle Blogger and Business Enthusiast

The World Health Organisation (WHO) has approved the first effective malaria vaccine after decades of trials; unfortunately, this vaccine is not meant for adults. More details about the new malaria preventive medicine will be shared in this article.

All you need to know about the first WHO-approved malaria vaccine, RTS,S

Clinicians and the general public have been excited about the news of the first malaria vaccine (RTS,S) approved by the World Health Organisation.

Malaria is a disease carried by a parasite called "Plasmodium". Five Plasmodium species causes malaria- P. falciparum, P. vivax, P. malariae, P. Ovale and P. Knowlesi. The first two are the most common malaria-causing culprits.

The Plasmodium parasites commonly infest the female anopheles mosquito, which feeds on humans. People develop malaria when a mosquito infected with the Plasmodium parasite bites them, thus transmitting the parasite to them.

Malaria is a killer disease. For years, the world, particularly the sub-Saharan region, has fought to eradicate this disease, yet it has continued to thrive among the populace.

According to the Centres for Disease Control (CDC), malaria is a threat to 87 countries and territories.2 Africa is the most affected because the Anopheles gambiae mosquito, responsible for high transmission of the plasmodium parasite, thrives there. Also, the weather condition in Africa favours the spread of malaria.

Even though the number of malaria cases and deaths have declined in recent years, this disease still poses a threat to many communities.5

The World Health Organisation (WHO) reported an estimated 229 million malaria cases worldwide in 2019. The estimated number of deaths due to malaria was 409,000 in 2019. 94% of the malaria cases and deaths were from Africa, and Nigeria bears 23%.6

The population groups at a higher risk of malaria include infants, children below the age of 5, patients with HIV and AIDS, travellers and pregnant women. In endemic areas, malaria may cause up to 10% of all deaths in children.4

There is now a vaccine for malaria

The key strategy for malaria control has been the use of insecticidal nets, treatment with artemisinin-based medicine combinations and active research into effective malaria vaccines.

The first attempt at malaria was more than three decades ago when people were vaccinated using high doses of irradiated sporozoites.1 This vaccination was considered impractical. Scientists have continued trying to develop an effective vaccine against malaria. None was approved until recently.

Now, the good news is that we now have an approved vaccine for malaria. On 6th October 2021, the WHO, in a news release, recommended a new malaria vaccine for children at risk of malaria.7

Photo by Mufid Majnun on Unsplash

The name of the malaria vaccine approved by the World Health Organisation is RTS,S/AS01 (RTS,S). RTS,S is a vaccine that fights against Plasmodium falciparum, the most common and deadliest malaria parasite, prevalent in the sub-Saharan African region.

This newly approved malaria vaccine (also called Mosquirix) was developed by the British pharmaceutical company GlaxoSmithKline (GSK.L).

Mosquirix is a result of 30 years of research by GSK through a partnership with PATH and with the support of other stakeholders and various African research centres.

The vaccine recommendation was made based on results obtained from a pilot study still ongoing in Kenya, Ghana and Malawi. The study started in 2019 and has extended to more than 800,000 children.

The approved malaria vaccine is only about 30% effective in reducing severe malaria cases.3 Therefore, health experts have stressed that all malaria interventions (including the use of insecticides and treated mosquito nets) remain vital.

Who the malaria vaccine (RTS,S) is meant for

The WHO recommended RTS,S malaria vaccine for children in areas at risk of malaria. This includes children in sub-Saharan Africa and other regions with moderate to high Plasmodium falciparum malaria transmission.

The WHO report read:

"WHO recommends that in the context of comprehensive malaria control the RTS,S/AS01 malaria vaccine be used for the prevention of P. falciparum in children living in regions with moderate to high transmission as defined by WHO."

According to WHO, some countries that carry a high malaria disease burden include Burkina Faso, the Democratic Republic of the Congo, Nigeria, Cameroon, Ghana, Mali, India, Niger, Mozambique, Uganda and the United Republic of Tanzania.

The malaria vaccine should be scheduled for administration in four doses for children from five months old in these countries and other countries moderately affected.

Why the newly approved malaria vaccine is not for adults

Photo by CDC on Unsplash

More than 2.3 million doses of the RTS,S malaria vaccine have been administered in 3 African countries. But the vaccine is meant to be administered to children, not to adults.

Why are adults not involved in the newly approved malaria vaccination scheme?

The various phases of the RTS,S trial had involved children and infants because they are the population group targeted for the malaria vaccination program.

Unlike adults, children have not yet built up immunity to parasitic infections like malaria. Therefore, children are more at risk of dying from malaria. Hence, the urgency in developing a vaccine that will reduce the occurrence of malaria in children.

Distribution of the malaria vaccine in Africa

Reuters reported that the African Union would start talks with the World Health Organisation on how to roll out and distribute the approved malaria vaccine to African countries.

According to the Director of the African Centres for Disease Control and Prevention, John Nkengsong, the organization doesn't know when the vaccine will be accessible to the African countries that need it most.

The director also added that it is not clear how quickly GSK will scale up the vaccine's production. Also, the cost per dose is not yet known.

One of the major challenges that will be faced in distributing the malaria vaccine in Africa is the availability of resources to support the rollout. If African countries quickly adopt the vaccine, its speed of deployment may be faster.

References

  1. Arama, C., & Troye-Blomberg, M. (2014). The path of malaria vaccine development: challenges and perspectives. Journal of internal medicine, 275(5), 456–466. https://doi.org/10.1111/joim.12223
  2. Centres for Disease Control and Prevention (CDC). (2021, January 26). Malaria's Impact Worldwide. https://www.cdc.gov/malaria/malaria_worldwide/impact.html
  3. Centres for Disease Control and Prevention (CDC). (2021, October 7). Malaria. https://www.cdc.gov/malaria/malaria_worldwide/reduction/vaccine.html
  4. Mehta, P. (2020, June 3). Pediatric Malaria. Medscape. https://www.who.int/news-room/fact-sheets/detail/malaria
  5. Nyasa, R., Fotabe, E., and Ndipe, R.N. (2021) Trends in malaria prevalence and risk factors associated with the disease in Nkongho-mbeng; a typical rural setting in the equatorial rainforest of the South West Region of Cameroon." Plos One. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251380
  6. World Health Organisation (WHO). (2021, April 1). Malaria. https://www.who.int/news-room/fact-sheets/detail/malaria
  7. World Health Organisation (WHO). (2021, October 6). WHO recommends groundbreaking malaria vaccine for children at risk. https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk