The World Health Organization (WHO) warned that public health officials had to do everything in their power to prevent "sustained transmission" of monkeypox infections before it reaches vulnerable groups.
"I am concerned about sustained transmission because it would suggest that the virus is establishing itself and it could move into high-risk groups including children, the immunocompromised and pregnant women," WHO chief Tedros Adhanom Ghebreyesus said in Geneva.
As of June 28, the US Centers for Disease Control and Prevention (CDC) listed more than 4,700 cases in countries where no previous monkeypox outbreaks had occurred. In addition, there were about 60 cases in African countries that have seen waves of the virus in the past. The WHO also reported more than 1,500 suspected cases from these countries at the beginning of June.
Last week, the majority on an emergency committee of independent experts had voted against declaring a "public health emergency of international concern" (PHEIC), which would be the WHO's highest alert level.
The PHEIC level has only been used six times, and is currently applied to the COVID-19 pandemic.
Though the committee voted against declaring an emergency, it left no doubt that the situation was serious, Tedros said. Eleven of the experts were against declaring an emergency, while three were in favor, he added.
"They advised that I should reconvene them quickly based on the evolving situation, which I will do," Tedros said.
Monkeypox is an infectious viral disease. Symptoms include fever and rash. Doctors have said most patients recover from it, though it can cause some lasting damage.