British health authorities said Friday the monkeypox outbreak across the country may be peaking and that the epidemic's growth rate has slowed.

The UK's Health Security Agency said in a statement there were "early signs that the outbreak is plateauing," with 2,859 cases detected since May. No deaths have been reported. Last month, authorities estimated the outbreak was doubling in size about every two weeks, but the number of new infections has dropped in recent weeks. 

"While the most recent data suggest the growth of the outbreak has slowed, we cannot be complacent," said Dr Meera Chand, Director of Clinical and Emerging Infections at the Health Security Agency. She said anyone who thought they might have monkeypox should skip meeting friends, social gatherings, and avoid sexual contact. 

The Health Security Agency said its most recent analysis of the outbreak "shows that monkeypox continues to be transmitted primarily in interconnected sexual networks of gay, bisexual, or men who have sex with other men." More than 70 percent of the UK's cases are in London.

British officials noted a small number of infections among women, but said there was not enough evidence to suggest there was sustained spread of monkeypox beyond gay and bisexual men; 99 percent of all cases in the UK are in men.

Scientists who analyzed monkeypox viruses in the UK noted a number of mutations compared to viruses circulating in Africa, but said there was no evidence those genetic changes made monkeypox any more transmissible. 

Experts suspect the monkeypox outbreaks in North America and Europe may have originated in Africa long before the disease started spreading via sex at two raves in Spain and Belgium.

The World Health Organization (WHO) said this week that 92 percent of monkeypox cases beyond Africa were likely infected through sex and its director-general recently appealed to vulnerable gay and bisexual men to consider reducing their sexual partners "for the moment."

To date, more than 26,000 monkeypox cases have been reported in nearly 90 countries, with a 19 percent increase in the last week. 

In June, British authorities expanded their vaccination strategy, offering vaccines not only to health workers treating monkeypox patients and high-risk contacts of patients, but to some men who are gay or bisexual and at high risk of catching the virus, including those with multiple sexual partners or who participate in group sex. 

Last month, the UK downgraded its assessment of the monkeypox outbreak and dropped a recommendation for the contacts of monkeypox cases to isolate for three weeks unless they have symptoms. The change was prompted by data showing that only a small number of contacts are ultimately sickened by monkeypox and a lack of evidence that the disease spreads without close, intimate or sexual contact. 

On Thursday, the U.S. declared its outbreak of monkeypox to be a national emergency. The WHO designated it a global emergency last month. 

Monkeypox spreads when people have close, physical contact with an infected person's lesions, their clothing or bedsheets. Most people recover without needing treatment, but the lesions can be extremely painful and more severe cases can result in complications including encephalitis and death.