R21/MM: The Revolutionary Malaria Vaccine And Its Links To A Covid-19 Jab
How Novavax's Covid-19 vaccine helped it in creating a vaccine for malaria as well.
The development of vaccines is considered to be one of the top achievements in public health. Vaccines were what helped eradicate smallpox in 1980 and now scientists are trying to eliminate malaria through jabs.
According to a research paper, published in April this year, experts from the University of Oxford and the Clinical Research Unit of Nanoro have conducted a clinical trial of a new malaria vaccine candidate called R21/MM.
After the trial, the researchers found that the vaccine demonstrated 77 per cent efficacy in children in western Africa’s Burkina Faso.
Malaria infects millions of people, kills thousands—mostly pregnant women and children—every year.
After dominating warm regions of the world for thousands of years, in the 20th century, malaria was successfully eliminated from much of the world by using insecticide spraying.
But that is not the case in sub-Sahara Africa. As per a study, climate change has helped malaria-carrying mosquitos to survive and turn into an endemic.
Vaccinating Against Malaria
Malaria causing parasite “Plasmodium” needs both blood-sucking insects and human to continue its life cycle.
The parasite inside the mosquitoes is transferred to a human host after a mosquito bites them.
Then it travels to the liver, replicates itself and spreads infection in the blood.
Unlike currently available Covid-19 vaccines, developing a targeted vaccine for malaria is tricky, as parasites have much more going on than viruses.
In simple words, while many Covid-19 vaccines are developed which target spike proteins of the SARS-CoV-2 virus, for malaria scientists cannot apply the same technology.
Derek Lowe, a researcher told Vox: “Malaria vaccine [development] has been a graveyard for really great ideas. We’ve learned about a lot of stuff that doesn’t work.”
Many researchers have been trying to find out a vaccine against malaria that could provide durable immunity.
The only vaccine against the disease is RTS, S, which has been around since 2016. But it has an initial efficacy of about 55 per cent and annual booster shots are also required.
However, in the case of the new vaccine R21/MM—a pre-erythrocytic vaccine—a vaccinated person is 77 per cent less likely to get the malaria disease. Researchers believe that it could decrease malaria caused deaths dramatically.
It targets the Plasmodium parasite during the earliest stages of its life cycle before it multiplies in the body.
This vaccine is also capable of targeting a specific protein present on the surface of the parasite.
To develop this vaccine the researchers tested many different adjuvants to understand which one provoked the strongest immune response.
They found a formulation called Matrix-M, which uses an extract from the bark of a Chilean soap tree.
This formulation is a proprietary invention of the American company called Novavax.
The Covid-19 vaccine developed by this company, NVX-CoV2373, contains a full-length, prefusion spike protein made using Novavax's recombinant nanoparticle technology and its proprietary saponin-based Matrix-M adjuvant.
Scientists used the R21 vaccine alone and with the Matrix-M adjuvant in 2016 during the initial trial, which was conducted on healthy adults in the United Kingdom.
According to a scientific report, published in October 2019, after finding success in the UK, researchers conducted another trial in Burkina Faso, where malaria is endemic.
This vaccine can be administered with three shots, along with a booster dose one year later.
The phase 2 study published this week has revealed that R21/MM’s single booster shot a year later returns the body’s immunity to the full level, achieved after the initial course of three vaccine doses.
The phase 3 trials, which have started at five sites across Africa, might also help to clarify whether all three shots and the booster are necessary.
According to a BBC report, Halidou Tinto, the principal investigator for the trial in Nanoro said: “We look forward to the upcoming phase 3 trial to demonstrate large-scale safety and efficacy data for a vaccine that is greatly needed in this region.”
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