The fourth anniversary of Syria’s civil war this week has prompted a brutal accounting of the conflict’s human cost: 210,000 dead and 840,000 wounded, an average life expectancy at birth that has plummeted by about 20 years since the fighting started.

The crisis has also ravaged the one group of people who might have been able to reduce those numbers: health workers.

A report in the March 14 issue of the medical journal, the Lancet, examines the staggering toll that years of war have taken on the Syrian health system, once considered among the best in the Arab world: more than 600 medical professionals killed, half the country’s public hospitals badly damaged or destroyed, hardly any ambulance service to speak of.

“Hundreds of doctors, nurses, dentists, pharmacists and paramedics have been killed, or fled to neighboring countries or farther afield, leaving a huge gap in experience and expertise that cannot be filled,” author Sophie Cousins wrote.

According to a separate report from Physicians for Human Rights released Wednesday, there have been 233 deliberate or indiscriminate attacks on 183 medical facilities in Syria since the conflict began. Nearly 90 percent of the attacks are attributable to the Syrian government, which is also responsible for 97 percent of the 610 deaths of medical personnel, the report said. In addition, the group found that 139 of those killed had been executed or tortured. 

In many cases, doctors and medical facilities are being specifically targeted, the group said — a tactic that harms not just health workers but also the civilians they treat.

“For every additional doctor killed or hospital destroyed, there are hundreds — even thousands — of Syrians who have nowhere to turn for health care,” the report said.

In major cities such as Aleppo, Homs and Deir al-Zour, more than 75 percent of medical professionals have been forced to leave, Syrian American Medical Society President Zaher Sahloul told Cousins. Those who remain are adopting fake names and working in secrecy, fearing reprisals for treating someone with the wrong political affiliations, he added.

The massive exodus of health professionals has left Syria with 15,000 fewer doctors — half the total number of certified physicians in the country.

“The brain drain of Syrian doctors … is one of the worst untold stories of the crisis,” Sahloul said.

The toll on Syria’s health-care system is evident in clinics and operating rooms across the country, where Cousins reports that newborn babies are dying in their incubators during power outages and patients are being knocked out with metal bars in the absence of anesthetics.

It’s also evident in Syria’s rising rates of illness. Vaccination rates have dropped from 90 to 52 percent, Physicians for Human Rights reported, contributing to outbreaks of scabies, typhoid and tuberculosis. In the last year the country has reported 4,200 cases of measles, after not reporting a single lab-confirmed case in either 2010 or 2011.

Polio, which hadn’t been seen in Syria since the 1990s, reemerged in 2013. A massive immunization campaign halted reports of new cases, but health experts told Cousins that the challenges of reporting and confirming cases lead them to believe that the outbreak may not have been completely reversed. And in a country with such poor vaccination rates, it may be only a matter of time until the disease returns, epidemiologist Martin Eichner said.

The conflict has also contributed to hundreds of thousands of deaths from non-communicable diseases, many of them preventable, Cousins said. The scarcity of doctors, medication and money to spend on them means typically non-life-threatening conditions such as diabetes and asthma can become deadly.

Meanwhile, the 3.3 million refugees who have fled to neighboring countries have strained those nations’ own health systems.

“People are fed up with Syria,” Evelyne Devaud, the Lebanon medical coordinator at Doctors Without Borders, told Cousins. “We need to have a solution tomorrow, but it won’t happen. The long-term current health situation is not sustainable.”