War-torn Yemen, where the overwhelming majority of the population is unvaccinated, is seeing coronavirus cases multiply and deaths soar, according to a report this week by the British charity Oxfam.

Oxfam found that Covid deaths had increased by more than fivefold in the past month and that recorded Covid cases had tripled. The charity said actual figures were likely to be much higher, with many unregistered cases and deaths.

The official Covid death toll about 1,658, and recorded cases have reached 8,789. But the situation in the country of about 30 million is hard to gauge. “Countless” others have died in their homes or have not been diagnosed because of scarce tests and hospital beds, Oxfam said.

Yemen is still embroiled in a war that began in 2014 when Iran-backed rebels know as the Houthis seized the country’s northwest, including the capital, Sana, sending the government into exile. The government has effectively collapsed, and tens of thousands have died.

The country already faced many health challenges before the coronavirus emerged. Hunger is widespread, medicines are hard to find and there have been outbreaks of cholera and other diseases.

The pandemic has only exacerbated the situation, and rights groups say that it is adding to the burden of an already wrecked health care system.

“Covid has made life even worse for people across the country,” Abdulwasea Mohammed, Oxfam’s policy and advocacy lead for Yemen, said by phone from Sana.

Some relief could come with vaccines, but fewer than 1 percent of Yemenis have so far received a single vaccine dose, and only 0.05 percent are fully vaccinated, according to Oxfam.

The country is relying on vaccines from the global Covax program. But Covax is struggling to meet its global supply target, and only half a million out of a promised 4.2 million doses have reached Yemen so far, Oxfam said.

Few isolation centers exist for Covid patients. The ones that are operating are found only in major cities like the capital Sana, and they are overflowing with people, Mr. Mohammed said. The poorly equipped hospitals are also seeing more people than they can accommodate. And many Yemenis cannot afford transportation to health care facilities.

With half the population having lost their source of income, staying at home means possibly dying of hunger for many Yemenis who have become day earners, Mr. Mohammed said. But appearing to be sick means being shunned, so if they have mild symptoms, people are reluctant to seek medical care or testing for the virus at the very few testing centers available.

In shelters that host over 4 million internally displaced people, a family of 10 is likely to share one small tent, making precautionary measures impossible.

“The country is not able to cope with another health crisis,” Mr. Mohammed said.

Most Yemenis survive on humanitarian aid, which Oxfam says has been in short supply. Only half of a $3.9 billion essential aid package requested by the United Nations from donor countries has been received. The health care system is dangerously underfunded, working with only 11 percent of what it needs, the organization says.

Some had hoped that the pandemic would force Yemen’s warring parties into a truce, but the war continues.

“If anything, it is amazing how little the pandemic has affected the fighting,” said Peter Salisbury, a senior analyst on Yemen for the International Crisis Group, in an interview.