Yi Lian wants to become a mother. But the 25-year-old carries the virus that causes hepatitis B, a potentially fatal liver disease, so she takes medicine to protect against infecting her future baby.

Yi’s monthly dose of pills would cost her more than half her teacher’s salary if she bought them in her hometown of Tianjin, a city in northern China. Luckily, in neighboring Beijing the medicine sells for just a third of the price. Yi told Sixth Tone she has found a pharmacy on the capital’s outskirts that stocks the medication she needs, and she either makes the 6-hour round-trip journey herself or asks a friend to help her with the errand.

Across China, uneven public health insurance coverage means people living with the hepatitis B virus travel across provinces to seek out significantly cheaper deals on their medicine.

According to official figures for 2015, there are about 28 million people with chronic hepatitis B, and a further 90 million carriers of the hepatitis B virus (HBV), in China. Only people whose viral load is too high need to take medicine. For pregnant, HBV-carrying women, Viread is considered the most effective treatment to lower their viral load so they can safely give birth. The medicine is patented and produced by British pharmaceutical company GlaxoSmithKline (GSK), and its active ingredient is tenofovir, an antiretroviral drug. Viread was approved for the Chinese market in 2014.

In China, HBV is most commonly transmitted at birth, and taking Viread means Yi is far less likely to transmit the virus when that time comes. According to the World Health Organization, 80 to 90 percent of infants infected during the first year of their life develop chronic conditions. In up to 30 percent of cases, people with chronic hepatitis B develop cirrhosis or liver cancer.

The drug’s uneven pricing comes from a negotiation in May between China’s national health authorities and GSK that resulted in a deal to lower the price of a bottle of Viread from 1,500 yuan ($220) to about 490 yuan across the country. Part of the agreement was that Viread would be covered by China’s public health insurance. But as of mid-October, 12 out of the mainland’s 31 provincial-level localities had yet to include the drug in their coverage plans, and as a result the prices there had not changed.

That’s why Viread still costs 1,500 yuan in Tianjin but can be bought for a third of the price in Beijing. And because the drug is included in Beijing’s health care coverage, residents actually end up paying even less, as they are reimbursed for more than half the cost. Non-Beijing residents, however, pay the full 490 yuan when they purchase the drug within the city.

A spokeswoman for GSK told Sixth Tone in a written statement that the company fully supports the Chinese government’s efforts to lower drug prices, and that it hopes expanded health insurance coverage will soon meet the needs of more Chinese hepatitis B patients.

Li Jichao, spokesman for nonprofit hepatitis B advocacy organization Yi You Charity, told Sixth Tone that it currently operates six online chat groups catering to around 3,000 hepatitis B patients and HBV carriers. About a tenth of these people use Viread, Li said, adding that almost all of them had bought the drug outside of their home provinces.

Inconsistent pricing is not unique to Viread. In May, the prices for two drugs used to treat lung cancer were halved after a comparable deal was made between pharmaceutical companies and the Chinese government. Similarly, however, 14 provinces had yet to include these drugs in their health insurance schemes as of Oct. 14. Lung cancer is the most common type of malignant tumor in China.

In 2015, Zhejiang became one of the first provinces in China to reduce the price of entecavir, another hepatitis B drug, by half after the conclusion of a round of bidding for government procurement contracts. “Hepatitis B patients and HBV carriers thronged to Zhejiang from every corner of China and stayed for two or three days to buy the drug,” said the spokesman Li. “Many of them joked at the time that they were contributing to the local tourism industry.”

At the end of September, the National Health and Family Planning Commission urged the 12 provinces where Viread still carries a high price tag to try their best to incorporate the drug into their public health insurance programs. But because provinces pay for the health care of their citizens, they are to some extent free to establish their own rules about how coverage is implemented. For example, Shanghai in 2010 provided coverage for 3,896 types of medicine, whereas neighboring Zhejiang province covered just 2,366. The percentages of costs that can be reimbursed can vary from one province to another as well.

As head of the government procurement center in southern China’s Hainan province, Xi Chuanliang is responsible for selecting the suppliers of medicines covered by Hainan’s health insurance program. He said each province has its own considerations when it comes to including a specific drug into its health insurance scheme. “They take into account factors such as the usage volume of a specific drug in their province,” he added. If usage and price are both high, some provinces might decide that the financial burden is too great for the government to bear, Xi explained.

The Tianjin government did not respond to Sixth Tone’s request for comment.

For HBV carrier Yi, the inclusion of Viread in Tianjin’s health coverage can’t come quickly enough. “I earn 2,600 to 2,700 yuan a month,” Yi said. “I don’t have a child yet, so 490 yuan is no problem. But when I do have a child, the cost will be hard for me to bear.”

(Header image: Chuck Savage/Corbis-RF/VCG)