LONDON, Dec 5 (Reuters) - Vaccines and treatments that could help tackle an mpox epidemic in the Democratic Republic of Congo are lying unused outside the country despite a death rate far higher than from the global outbreak that began last year.

Stigma, regulatory hurdles and competing disease outbreaks are all factors holding back the response, according to almost a dozen scientists, public health officials and drugmakers involved.

Since January, at least 581 people have died of mpox in Congo out of 12,569 suspected cases, compared to 167 deaths among 91,788 reported cases in 116 other countries since January 2022, according to the World Health Organization.

Mpox is a viral infection that spreads through close contact and causes flu-like symptoms and pus-filled skin lesions.

The WHO sent a team to the country last month to help the authorities there, but there are still no treatments or vaccines available for use in Congo outside of clinical trials. A team working for Médecins Sans Frontières (Doctors without Borders) in one district confirmed the lack of specific tools to fight the disease.

That is in part because the government in Congo, one of the world's poorest countries, has not asked to buy any or applied for donations, according to representatives from the drugmakers as well as from high-income countries with stockpiles.

Congo is fighting a number of other outbreaks, including measles and cholera, and around a quarter of its population requires humanitarian assistance. Conflict has also intensified in eastern Congo in recent years.

Mpox was re-named from monkeypox last year to avoid stigma, but increasing evidence that the disease can spread through sexual contact, particularly among men who have sex with men, has renewed fears of discrimination.

In addition, medical mpox countermeasures have not been cleared for use by Congo regulators, the countries with stockpiles and drugmakers said, another obstacle to selling or donating doses. The Congolese government did not respond to requests for comment.

An attempt to donate doses of mpox vaccine has been stalled for more than a year for this reason, Bavarian Nordic Chief Executive Paul Chaplin said in a statement.

The company, which makes the vaccine Jynneos, is supporting donation by an organization that bought doses, and has submitted a dossier for a domestic emergency use authorization in Congo, the CEO said.

Global health officials said a lack of urgency was a sign the world had learned nothing from the unequal access to vaccines during the COVID-19 pandemic.

“This is a stain on our humanity,” said Winnie Byanyima, the head of the United Nations AIDS programme, who has been vocal on inequality and stigma during pandemics. “What are we waiting for?”

Both the mpox vaccine and treatment were originally developed to tackle a re-emergence of smallpox, a related deadly disease eradicated decades ago. Wealthy nations keep small stockpiles in case the disease returns, and repurposed some when mpox began to spread to countries where it was not endemic.

The WHO also has access to a small stockpile of both, and requires applications from countries that need them. The organization did not respond to requests for comment.

'HOSTILE' ENVIRONMENT

Recent evidence has shown for the first time that the type of mpox spreading in Congo, known as clade I, can be transmitted through sexual contact. This proved to be the main transmission mode for the less deadly strain of the disease that broke out globally last year, chiefly among gay, bisexual and other men who have sex with men.

It was previously thought that both types of mpox spread mainly through close contact among humans after spilling over from an infected animal through bites, scratches, hunting, or cooking.

African scientists said they were concerned the sexual stigma could hamper spread prevention. While homosexuality is not illegal in Congo, it is not widely accepted.

“This is taking place in an environment hostile to homosexual activities,” said Oyewale Tomori, a leading Nigerian virologist with mpox expertise. “This is likely to hamper field investigations... and formulation of appropriate response and control measures.”

SIGA Technologies, which makes the antiviral drug TPOXX (tecovirimat), said this could make a treatment easier to deploy. A vaccine would require people to come forward potentially admitting they belong to the high risk group.

Unlike the vaccine, the treatment has not yet been approved by the U.S. Food and Drug Administration. Its use worldwide is under emergency protocols applied by each country. While no gold-standard clinical trial has yet proved its safety and effectiveness, real-world data supports this, SIGA said.

“If the clinical trial shows what we expect it to show," said Jay Varma, chief medical officer at SIGA, "there will hopefully then be more political interest in trying to come up with a long-term procurement and delivery strategy.” (Reporting by Jennifer Rigby, editing by Michele Gershberg and Bill Berkrot)