Oxford: No one had developed a vaccine against it till three years ago parasitic disease, There are now two vaccines against malaria: RTS,S and R21.

Adrian Hill, Director of Jenner Institute at the University of Oxford and principal investigator R21 vaccineNadine tells Dreyer why he thinks this is a great era for malaria control.

Why is malaria such a difficult disease to defeat?

Malaria has been around for 30 million years. Man does not have it.

Our hominoid predecessors were becoming infected with malaria parasites millions of years ago, so these parasites had plenty of clever tricks to avoid the immune system long before we arrived. Homo sapiens first evolved in Africa about 315,000 years ago.

Malaria is not a virus nor is it a bacteria. It is a protozoan parasite, which is thousands of times larger than a normal virus. A good comparison is how many genes it has. There are about a dozen of Covid-19, about 5,000 of malaria.

Additionally, the malaria parasite goes through four life cycle stages. This is as complicated as it gets with infectious pathogen,

Medical researchers have been trying to create malaria vaccines for more than 100 years. It took us 30 years of research at Oxford.

How does the R21/Matrix-M vaccine work?

The four malaria life cycles are highly distinct, with different antigens expressed. An antigen is any substance that causes the body to make an immune response against that substance.

We targeted sporozoites, which are the form that the mosquito inoculates into your skin. We were working to trap them before they could reach the liver and then continue their life cycle by multiplying aggressively.

Each mosquito injects a small number of sporozoites, perhaps 20, into the skin. If you get past those 20, you’ve won. If someone succeeds, you lost. The bad news is that you only have a few minutes.

So you need exceptionally high levels of antibodies that the parasite has not seen before and has not learned to evolve against. Technically it’s like designing a car that is 10 times faster than any other car on the road.

In Africa, one child dies every minute from malaria. Why are children more sensitive than adults?

Nearly 80% of all malaria deaths in Africa are in children under five years of age. In Africa you are most likely to die from malaria when you are one year old.

For the first six months you are largely protected by your mother’s immunity and the antibodies she transferred during pregnancy.

If you live to be two or three years old, and you’ve had a few episodes of malaria and you’re still alive, you have a little bit of immunity. It improves with time.

Some children have up to eight episodes over three or four months. They become quite unwell the first time, and three weeks later they have to compete a second time, and so on.

Natural immunity doesn’t work until you’ve had multiple infections and that’s why adults are usually safe from malaria and don’t get very unwell.

Without malaria, children would be generally healthy – the disease leaves you vulnerable to other infections.

What about the speed of the vaccine rollout?

We are disappointed that it has taken more than six months to develop the R21 vaccine since it was approved in October last year. Lakhs of doses of R21 are kept in refrigerators in India.

Standard deployment involves a lot of organization and processes that may not seem necessary.

Compare this to a COVID-19 vaccine from Oxford and AstraZeneca, which was approved on New Year’s Eve 2020 and rolled out in several countries the very next week.

That same year, malaria killed more people in Africa than COVID-19.

First malaria vaccineRTS,S, has already been given to millions of children in a large safety trial and the uptake is really high, so large-scale coverage can be achieved in Africa.

How big a role will vaccines play in the fight to eradicate malaria? We really think we now have an opportunity to make a big impact.

No one is sure how much old equipment like pesticides and mosquito nets we will have to carry around. The advice is to keep them all.

But mosquitoes are developing resistance to pesticides. Anti-malaria drugs last only for a few days and the parasites are developing resistance to these drugs as well.

Approximately 40 million children are born each year in malaria areas in Africa who would benefit from the vaccine. The R21/Matrix-M is designed to be mass manufactured. Serum Institute of India, our manufacturing and commercial partner, can produce crores of doses every year.

The second real advantage is its low cost. At US$3.90 per dose, R21/Matrix-M appears to be the most effective single intervention we can deploy against malaria.

Worldwide, US$5 billion is currently allocated to fight malaria each year.

We are optimistic that if this money is spent wisely we can make a big difference. Purchasing 200 million doses of the R21/Matrix-M vaccine will cost US$800 million.

Being in the field I am aware of other vaccines arriving. Some are targeting the blood stage and some are targeting the mosquito stage of malaria, which is very exciting. This looks like a great era for malaria control.

More than 600,000 people die from malaria every year. With the deployment of low-cost, very effective vaccines, we should be able to bring this down to 200,000 or less by the end of this decade.

then there will be a final game malaria eradication Worldwide, which should actually happen in the 2030s. NSA