Aid workers in Ukraine are warning that the central government’s decision to cut off humanitarian aid to the separatist-held east in November has resulted in urgent shortages of narcotics substitutes for drug addicts — a policy that could undo years of progress in curbing the country’s fast-growing AIDS epidemic.

Thousands of people in rebel-held Donetsk and Luhansk, as well as at least 800 others in the Crimean Peninsula — annexed by Russia in May — are in dire need of opioid substitution therapy (OST) as a means of preventing the contraction or transmission of HIV. Studies show that drug addicts who take methadone or other OST, in lieu of narcotics purchased on the street, are substantially less likely to share HIV-infected needles, or to have unprotected sex in order to score drugs.

But in a bid to suffocate the Russian-backed rebels, Kiev banned all government support to the separatist strongholds in November, ignoring urgent pleas from aid groups like AIDS Alliance Ukraine to at least let in narcotic treatment, along with clean syringes and condoms.

Supplies are now running dangerously low, Alliance Ukraine says, with more than 300 OST patients in Donetsk and Luhansk losing access to treatment and another 550 patients set to run out within a month.

“Unfortunately this broken chain of supply is not a priority for the government of Ukraine because of the war,” said Pavlo Skala, Alliance Ukraine’s associate director. “The irresponsibility of the government has made it almost impossible to provide these territories with narcotic drugs,” he said. As a result, new cases of HIV — as well as tuberculosis and other communicable diseases — will likely increase, he added.

More than 3,500 people died of AIDS in Ukraine in 2013, according to World Health Organization (WHO) statistics. Together, Ukraine and Russia are home to 90 percent of the HIV cases diagnosed in Europe, with a 0.8 HIV prevalence in Ukraine and between 0.8 and 1.4 in Russia, according to HIV/AIDS charity Avert.

The spike in these countries has its origins in the economic crisis of the mid-1990s, which saw drug trafficking and usage skyrocket across Eastern Europe.

In the past few years, however, Ukraine has managed a stable declining rate in new HIV infections among drug users, in large part thanks to the country’s extensive harm-reduction programs. By contrast, Russia, which bans OST and has limited clean-needle exchange programs, has seen a growing number of cases.

But the war has threatened to unravel much of Ukraine’s progress, especially in the east, which has one of the highest rates of HIV and tuberculosis in all of Europe.

Acute shortages have already begun to take a deadly toll in Crimea, where Russia has prevented narcotics from entering since it took over the peninsula in May (OST is illegal under Russian law, due to fears it perpetuates drug use). According to Skala, 10 percent of those who lost access to treatment — about 80 of 800 people — have died, likely due to overdose from more dangerous drugs, suicide, or other concurrent chronic illnesses.

But Skala says the shortages in eastern Ukraine are largely the fault of Kiev, which has failed to approve an emergency request for an exception to the blockade proposed by his and other aid groups, along with the Ministry of Health. Hundreds of patients signed an open letter to accompany the request, saying many would consider suicide rather than “returning to street drugs and a life of crime.”

The methadone and other OST supplies have already been paid for by the Global Fund to Fight AIDS, Tuberculosis, and Malaria, which distributed money to civil organizations like Alliance Ukraine. All Kiev needs to do is sign off on their delivery, but Skala feared that could take “weeks or months."

That might be too late for the roughly 150 methadone patients at Donetsk’s drug addiction treatment facility who face termination of their treatment within one week. According to Yulia Drozd, the center’s deputy director, 60 percent of these individuals are HIV-positive and many have Hepatitis C or tuberculosis.

Dropping methadone treatment is “essentially a death sentence for them,” Drozd told The Guardian newspaper.

In addition to the methadone shortage, condoms are getting expensive and scarce. HIV testing rates have also declined by least 20 percent. The more than 600,000 internally displaced Ukrainians — as well as tens of thousands more who have taken shelter across the border in Russia — are difficult to track for testing and treatment. And many health workers have fled the east, or simply quit their jobs due to violence or lack of pay.

Even before the war, antiretroviral treatment (ART) was only reaching about 24 percent of those living with HIV, according to the latest WHO statistics provided to Al Jazeera. It is unclear how the war has affected ART provisions across the country.

Yet another factor is that international funding is drying up. As Ukrainian civil society, if not the government, proved increasingly able to manage its epidemic, the Global Fund had begun to redistribute more of its funding towards poorer countries in the southern hemisphere — a policy shift decided before Ukraine’s war erupted last spring.