Science’s COVID-19 reporting is supported by the Pulitzer Center.

An herbal tonic developed in Madagascar and touted as a cure for COVID-19 could fuel drug-resistant malaria in Africa, scientists warn. Several African countries have said they are placing orders for the brew, whose efficacy has yet to be shown.

Branded Covid-Organics, the therapy was developed by the Malagasy Institute of Applied Research (IMRA). Its chief ingredient is reported to be sweet wormwood (Artemisia annua), a plant of Asian origin that gave rise to the antimalarial drug artemisinin. At its launch last month, Malagasy President Andry Rajoelina claimed the tonic had passed scientific scrutiny and cured two patients of COVID-19. The island nation has 151 confirmed coronavirus cases and no deaths.

But it’s unclear how Covid-Organics is prepared, and IMRA has not reported any data on its efficacy or side effects. (The institute did not respond to a request for comment.) “It is a drug whose scientific evidence has not yet been established, and which risks damaging the health of the population, in particular that of children,” the National Academy of Medicine of Madagascar cautioned in a statement last month.

Despite such warnings, other African leaders are keen to obtain the product. “We will send a plane to bring the drugs so that Tanzanians can also benefit,” Tanzanian President John Magufuli said earlier this week. Denis Sassou Nguesso, president of the Republic of the Congo, plans to “adopt” the tonic as well, according to a tweet by his government’s spokesperson. That has fueled fears that the concoction could drive resistance to malaria drugs.

Artemisinin is the cornerstone of so-called artemisinin-based combination therapies, which have helped bring down malaria deaths from more than 1 million to about 400,000 every year, says Kevin Marsh of the University of Oxford, who spent decades studying malaria in Kenya. “We totally depend on artemisinin for malaria in every country of the world, so we are very worried about resistance,” Marsh says—especially in Africa, where 90% of the world’s malaria deaths occur.

To prevent resistance taking hold, most artemisinin-based malaria treatments include a second antimalarial drug, so that if the parasite develops resistance to artemisinin, the other drug will still kill it. The World Health Organization (WHO) strongly discourages countries from using artemisinin to treat malaria on its own as a “monotherapy,” because it could hasten the development of drug resistance. An October 2019 WHO report also recommended against the use of the Artemisia plant to treat or prevent malaria. Yet a flood of Artemisia-based COVID-19 treatments would amount to massive monotherapy use, Marsh says. “It’s a big, big issue,” he says. 

Others don’t think the threat is that serious. African pharmacies have long sold artemisinin monotherapies, says Philip Bejon, executive director of the KEMRI-Wellcome Trust Research Programme, which is based in Kilifi, Kenya. And mutations in Plasmodium falciparum, the malaria parasite, that seem to confer resistance to artemisinin in Southeast Asia, “don’t seem to take hold and spread,” in Africa, Bejon says. It’s also not clear how much artemisinin ends up in herbal remedies—hot water can inactivate it. “My guess is that Africa is low risk for artemisinin resistance,” Bejon says.

There are some hints that artemisinin might have an effect against SARS-CoV-2, the virus that causes COVID-19. In 2005, Chinese scientists reported that an alcoholic extract from A. annua was able to neutralize its cousin, the severe acute respiratory syndrome (SARS) virus, in a petri dish. (The extract was never tested against SARS in animals or humans, however.) Based on that study, scientists at the Max Planck Institute of Colloids and Interfaces are now collaborating with ArtemiLife, a U.S. company that grows sweet wormwood, to test plant extracts on SARS-CoV-2 in vitro. Lead scientist Peter Seeberger says they expect to publish the results “very soon.”

The African Union has asked the Malagasy government to produce the scientific evidence to back up its treatment, and says it will work with the Africa Centres for Disease Control and Prevention to assess its safety and efficacy once it has those data. But even if the extract, or artemisinin alone, proved effective in treating COVID-19, its use would pose a huge ethical problem, Marsh says: “We’d have a big issue on how to use it on COVID-19 without sacrificing it as an antimalarial treatment.”

The embrace of an “African” therapy for COVID-19 comes amid a climate of deep distrust of Western medical science in parts of African societies. Press stories frequently warn about experimental treatments being tested on hapless Africans; in March, a media storm erupted after French scientists suggested a coronavirus vaccine could be trialed on the continent. Now, some African scientists ask why leaders welcome with open arms a locally produced treatment for which no evidence appears to exist.

“If Africans are really concerned about being guinea pigs of science, they should be just as concerned about both Western and African science,” says Catherine Kyobutungi, executive director of the African Population and Health Research Center in Nairobi, Kenya. “It is disingenuous to cry foul and demand the most stringent forms of accountability for one type of science and then bend the rules for another.”