Saturday, 30th September 2023

‘Malaria vaccine still has many hurdles to cross’

By Chukwuma Muanya
14 October 2021   |   3:34 am
•Scientists hail historic malaria jab approval but point to challenges ahead •Say WHO-approved RTS,S vaccine has modest efficacy, requires complex regimen of doses •At N3,250 per dose, vaccine rollout would cost N211.25b yearly to administer in ten African countries Scientists have hailed approval by the World Health Organisation (WHO) of the first and, to date,…

A baby receives a dose of the RTS,S vaccine for malaria in Cape Coast, Ghana in 2019. Credit: Cristina Aldehuela/AFP/Getty/Nature

•Scientists hail historic malaria jab approval but point to challenges ahead
•Say WHO-approved RTS,S vaccine has modest efficacy, requires complex regimen of doses
•At N3,250 per dose, vaccine rollout would cost N211.25b yearly to administer in ten African countries

Scientists have hailed approval by the World Health Organisation (WHO) of the first and, to date, the only vaccine that can significantly reduce malaria in children – the group at highest risk of dying from malaria. The vaccine is complementary to other proven measures to fight malaria.

But other schools of thought have expressed concerns over the deployment of the WHO-approved RTS,S vaccine that has only moderate efficacy.

They argue the vaccine has modest efficacy and requires complex regimen of doses, and so ample funding and clear communication will be crucial to success.

However, Prince Ned Nwoko Foundation aims to lead national response and implementation of vaccine in collaboration with the Federal Government (FG) and other altruistic partners in Nigeria.

According to a study published in the journal Nature, compared with other childhood vaccinations, RTS,S has only modest efficacy, preventing about 30 per cent of severe malaria cases after a series of four injections in children under the age of five.

Nevertheless, one modelling study suggests that it could prevent the deaths of 23,000 children a year, if the full series of doses were given to all kids in countries with a high incidence of malaria — making a significant dent in the tremendous toll of the disease, which killed 411,000 people in 2018.

Leaders across Africa are now considering whether and how to deploy the vaccine. In Mali, for example, malaria researcher Alassane Dicko at the University of Bamako told Nature that, soon after the WHO’s announcement, the nation’s minister of health asked him what Mali needed to do to get the vaccine.

“I told her we need to push as a country, at the highest levels of our government, to make this vaccine available at an affordable cost as soon as possible,” he said.

A consultant malariologist with Prince Ned Nwoko Foundation Africa Malaria Eradication Project, Prof. Chioma Amajoh, told The Guardian:

“The Prince Ned Nwoko Foundation aims to lead a National response and the implementation of the RTS,S/AS01 malaria vaccine in collaboration with the Federal Government and other altruistic partners in Nigeria

“The Honourable Minister of Health has approved the implementation of this project in Nigeria.

“The efficacy of the RTS,S/AS01 vaccine was established in the Phase 3 clinical trial; children who received four doses of the vaccine had a significantly lower risk of developing malaria, including severe malaria.”

Amajoh said beginning in 2019, three sub-Saharan African countries – Ghana, Kenya and Malawi – led the introduction of the vaccine in selected areas of moderate-to-high malaria transmission as part of a large-scale pilot programme coordinated by WHO. Unfortunately, she said, Nigeria was not included in the Malaria vaccine Implementation Programme (MVIP).

Amajoh said MVIP, coordinated by WHO, was designed to address several outstanding questions related to the public health use of the vaccine.

Specifically, she said the MVIP would assess the feasibility of administering the recommended four doses of the vaccine in children; the vaccine’s potential role in reducing childhood deaths; and its safety in the context of routine use.

The malariologist said data and information derived from the pilot will inform a WHO policy recommendation on the broader use of the vaccine.

Founder of Prince Ned Nwoko Foundation, Prince Ned Nwoko, had on World Malaria Day, April 25, 2021, said that a vaccine for malaria in Nigeria would be available in the next six months.

He added that alongside the vaccine were issues of sanitation, fumigation and proper waste management to help in curbing the menace of malaria.

The former member of the House of Representatives from Delta State said the foundation was collaborating with multinational companies in the United States of America and the United Kingdom to produce the vaccines.

Researchers have been developing and testing the RTS,S vaccine — also known by its brand name, Mosquirix — since 1987, at a cost of more than US$750 million. This was funded mainly by the Bill & Melinda Gates Foundation in Seattle, Washington, and the London-based pharmaceutical firm GlaxoSmithKline (GSK).

Although clinical trials concluded in 2015, the WHO recommended pilot studies to determine the feasibility and safety of this multi-dose vaccine outside a clinical trial.

Gavi, the Vaccine Alliance, a health partnership based in Geneva, Switzerland, helped to fund the pilot programmes, which have distributed 2.3 million vaccine doses across Ghana, Kenya and Malawi. It reports that in these studies, hospitalisations from severe malaria decreased by about 30 per cent. These results gave the WHO the confidence to recommend that four doses of the vaccine be given to children living in regions with moderate to high levels of malaria transmission.

However, Dicko said countries might achieve even greater drops in hospitalisations and deaths through tailored rollouts.In August, he and his colleagues published results from a clinical trial finding that the RTS,S vaccine reduced childhood malaria deaths by 73 per cent if children received three doses in the run-up to the rainy season — when malaria peaks — and another dose before the rainy season in the two subsequent years. Notably, this was done in conjunction with a method called seasonal malaria chemoprevention, in which healthy children take a monthly dose of anti-malaria drugs to help prevent the disease.

In addition to deciding how to deploy the vaccine, countries will need to determine how much it will cost to purchase and distribute it — and whether donors will help to foot the bill.

The vaccine manufacturer, GSK, released a statement pledging to make 15 million yearly doses available at just above the cost of production. However, roughly 100 million doses will be needed yearly if all children in high burden countries are to receive the shots.

Some researchers fear that the excitement over a vaccine will overshadow existing malaria control measures that are already often underfunded, including insecticide programmes and functional health systems.

At a potential cost of about $5 per dose, researchers suggest the vaccine rollout, including its distribution, would cost around $325 million to administer each year across ten African countries with a high incidence of malaria. They point out that in some of these countries, other malaria measures have faltered because of a lack of support.

A malaria researcher at the Institute for Health Research, Epidemiological Surveillance and Training in Dakar, Senegal, Badara Cisse, said: “I respect the researchers involved with this massive effort, but the reality is that so much money has been poured into this vaccine, even when the results from studies are disappointing. I don’t think a 30 per cent effective vaccine would be acceptable for Americans.”

Still, he and James Tibenderana, a Ugandan epidemiologist at the Malaria Consortium in London, said the RTS,S vaccine could be impactful in some regions. To achieve that, Tibenderana stressed the need for extensive communication campaigns, so that misinformation doesn’t hamper the rollout.

“People will wonder why a 30-year-old, partially effective vaccine is suddenly being introduced during a pandemic — and targeted only at Africans,” he said. “The misinformation around COVID-19 vaccines should teach us that we can’t take community trust for granted.”

Despite the long road ahead, he and others are grateful for the WHO’s decision. “With the devastation of COVID-19, and with progress stalled on malaria control, and news of resistance to anti-malaria drugs, it’s uplifting to see some positive news,” he said.

The RTS,S/AS01 (MosquirixTM) malaria vaccine was created in 1987 in Partnership by PATH, Malaria Vaccine Imitative (MVI), GlaxoSmithKline (GSK), and several academic and research institutions. The RTS,S is a pre-erythrocyte vaccine that has demonstrated considerable efficacy and safety following robust Phase III clinical trials in multiple sites. The large multinational that enrolled 15,459 children (conducted in two age categories of children: six-12 weeks and five-17 months) in 11 clinical trial centres in seven countries namely: Burkina Faso, Gabon, Malawi, Mozambique, Ghana, Tanzania, and Kenya in from May 2009 – 2014.