A study conducted by Spanish scientists found that 4 out of 10 of those infected with monkeypox experience it in a severe form and are in need of medical care, according to Spanish media on Tuesday.

According to El Mundo, the study published in The Lancet medical journal studied the data input of more than 180 patients from three Spanish health facilities. 

See more: Monkeypox: Should you be worried?

"One of the most frequent and painful complications of monkeypox and even the cause of hospitalization is proctitis in 25% of cases," said Eloy Tarin Vicente, one of the authors of the study, according to the report. He revealed that 40% of patients required medical treatment to reduce pain.

Of the 4,436 patients diagnosed with monkeypox in Spain, 139 (2.8%) were hospitalized, and 237 out of 3,546 (6.9%) reported treatment complications - mainly mouth ulcers and secondary bacterial infections, the Spanish Health Ministry said, according to the newspaper.

Last month, the World Health Organization declared monkeypox an international public health emergency. More than 28,000 cases of monkeypox have been reported across over 70 countries. 

Monkeypox less dangerous & contagious than smallpox

A viral infection resembling smallpox and first detected in humans in 1970, monkeypox is less dangerous and contagious than smallpox, which was eradicated in 1980.

95% of cases have been transmitted through sexual activity, according to a study of 528 people in 16 countries published in the New England Journal of Medicine - the largest research to date.

The European Union's drug watchdog recommended the approval of Imvanex, a smallpox vaccine, to treat monkeypox.

Imvanex, developed by Danish drugmaker Bavarian Nordic, has been approved in the EU since 2013 for the prevention of smallpox. 

It was also considered a potential vaccine for monkeypox because of the similarity between the monkeypox virus and the smallpox virus.  

The first symptoms of monkeypox are fever, headaches, muscle pain, and back pain during the course of five days. 

Rashes subsequently appear on the face, palms of hands, and soles of feet, followed by lesions, spots, and finally scabs.