Hospitals in Madagascar have been struggling to cope with a surge of Covid-19 cases, while the president has been promoting an unproven product he says can cure the disease despite the World Health Organization (WHO) warning against using untested remedies.

Cases have quadrupled in the past month in the Indian Ocean island, with more than 13,000 infections and 162 deaths from coronavirus, which has spread to all but one of its 22 regions.

Despite the spike, President Andry Rajoelina stands by the herbal concoction called Covid-Organics, which was launched to great fanfare in April.

It is produced by the Malagasy Institute of Applied Research from the artemisia plant – the source of an ingredient used in a malaria treatment – and other Malagasy plants.

The drink has been marketed as a prevention and remedy – and for the last four months been offered to children at school.

Earlier in the month the president was out again distributing the tonic, along with essentials such as rice, oil, sugar, to poor communities in the capital, Antananarivo.

He faced criticism for drawing crowds during a lockdown, but his attitude remained upbeat: “The epidemic won’t last, it’s only passing through and we will defeat it.”

He also suggested that the number of infected people was not high in suburbs of the capital where the free distribution of the drink had started a few months ago.

The WHO says it welcomes innovations based on traditional remedies but it wants scientific evidence before backing their use.

So far no results of clinical trials have been made public – though that has not stopped stop the tonic from becoming a source of African pride for some. Free shipments have been sent to dozens of African countries.