Researchers have found that the drug used during the global monkeypox outbreak from 2022 to 2023 is not effective against the more severe strain of the virus that is rapidly spreading in Africa.

Preliminary results from a study conducted by researchers from the Democratic Republic of the Congo (DRC) and the United States indicate that the antiviral drug "Tecovirimat" did not shorten the duration of the illness among children and adults infected in the DRC, according to a report by Politico.

There are two subtypes of the virus: Clade 1, which is more deadly and spreads in the Congo Basin of Central Africa, and Clade 2, which caused the global outbreak in West Africa in 2022.

Read more: Monkeypox declared global public health emergency by WHO

Clade 1 particularly affects children, a pattern not observed in the 2022 outbreak, prompting the World Health Organization (WHO) to declare a global health emergency on Wednesday.

Jane Marrazzo, Director of the US National Institute of Allergy and Infectious Diseases, described the findings as "disappointing."

Despite this, researchers emphasized that hospitalization could still help save patients' lives.

The WHO declared the monkeypox outbreak in Africa a global health emergency on Wednesday, marking the highest level of alert the organization can issue.

This announcement came after the disease spread from the DRC to neighboring countries like Burundi, Kenya, Rwanda, and Uganda.

Since the outbreak began in January 2023, over 27,000 cases have been reported, with more than 1,100 deaths, most of them children.

The virus was first discovered in 1958 in Denmark among monkeys used for research, with the first human case recorded in the DRC in 1970.