The World Health Organization (WHO) has included artesunate, a treatment for malaria, in its latest group of drugs to be tested for their capacity to treat Covid-19 patients in hospital.

It is one of the derivatives of artemisinin, extracted from the artemisia annua plant, the main herb behind Madagascar's purported Covid-19 herbal cure announced last year.

Artesunate will be part of a global trial together with imatinib, a drug used for certain cancers, and infliximab used for diseases of the immune system.

The study is expected to be completed by May next year.

"These drugs were chosen by an independent panel of experts that evaluates all the available evidence on all potential therapeutics,” said Tedros Adhanom Ghebreyesus, WHO director general.

The inclusion of the drug is not an indication that it is effective in treating Covid-19.

Previously, four drugs were evaluated and the results showed all of them - remdesivir, hydroxychloroquine, lopinavir and interferon - had little or no effect on hospitalized patients with Covid.