Rich countries have several hundred million doses of vaccines that could help fight an mpox outbreak in Africa, where donated shots fall far short of what is needed, according to a Reuters tally of public statements, documents and estimates from non-governmental organizations.

The shots have been stockpiled for years by countries such as Japan, the United States and Canada in case smallpox, an eradicated disease that is the more dangerous cousin of mpox, ever makes a comeback. Some of the vaccines were used outside of Africa in 2022 when mpox spread globally.

A small fraction of those doses could help curb what is now the biggest mpox outbreak on record in the Democratic Republic of Congo and neighboring countries, disease experts say.

Fewer than 4 million doses have been pledged for donation out of an estimated 18 million to 22 million that are needed to vaccinate 10 million people in the next six months, depending on the vaccine, Africa’s Centers for Disease Control and Prevention said in a statement.