Governments are deploying vaccines and treatments that were first approved for smallpox but also work for monkeypox.
The US government has distributed 600,000 doses of Bavarian Nordic's Jynneos vaccine and deployed 14,000 of Siga Technologies' TPOXX treatment, officials said, though they did not disclose how many have been administered.
Walensky said the government aims to vaccinate more than 1.6 million high-risk individuals.
US Food and Drug Administration Commissioner Robert Califf said the agency was considering freeing up more Jynneos vaccine doses by allowing doctors to draw 5 doses of vaccine from each vial instead of the current 1 dose by using a different subcutaneous method of inoculation.
US President Joe Biden this month appointed two federal officials to co-ordinate his administration's response to monkeypox, after declarations of emergencies by California, Illinois and New York.
First identified in monkeys in 1958, the disease has mild symptoms including fever, aches and pus-filled skin lesions, and people tend to recover from it within two to four weeks, the WHO says. It spreads through close physical contact and is rarely fatal.
Anthony Fauci, Biden's chief medical adviser, told Reuters on Thursday that it was critical to engage leaders from the gay community as part of efforts to rein in the outbreak, but cautioned against stigmatising the lifestyle.
“Engagement of the community has always proven to be successful,” Fauci said.