The two-lane road south from Gwangju Songjeong Station runs past rice paddies and weather-worn farmhouses before climbing into the wooded hills of Hwasun, a rural county about three hours from Seoul.

At the top stands GC Biopharma’s anthrax vaccine facility, a blocky concrete complex set apart from the surrounding farmland.

On a humid afternoon last Tuesday, about 30 government officials, company staff members, and reporters toured the site. Behind sealed glass, two technicians in full clean-room suits monitored a 400-liter fermenter. The broth inside held genetically engineered Bacillus brevis, producing the protective antigen in Barythrax, now the world’s first recombinant anthrax vaccine to win regulatory approval.

The shot received the green light in April, capping nearly three decades of co-development by drugmaker GC Biopharma and the Korea Disease Control and Prevention Agency (KDCA).

A 526-day review sealed the license and made Korea one of only three countries that can produce anthrax vaccine on their own soil, alongside the United States and the United Kingdom.

“The biggest challenge was time itself,” said Lee Jae-woo, GC Biopharma's chief development officer, during the facility tour attended by Korea Biomedical Review. Standards kept shifting, he said, and early data had to be repeated. “Generating those new datasets was brutal, but the KDCA stayed with us the whole way.”

A ‘safer, simpler’ shot

Korea has in recent years pushed for vaccine sovereignty, a term officials use to describe the ability to manufacture essential vaccines domestically, especially during global emergencies. Barythrax represents not only a scientific milestone but a geopolitical one: a biodefense tool developed in Korea, for Korea, at a fraction of the cost of its U.S. counterpart.

Until now, Korea relied on BioThrax, a five-dose vaccine made by Emergent BioSolutions in Maryland and stockpiled by the U.S. government.

Barythrax takes a different approach. It uses a recombinant protein grown in a harmless bacterium, not filtrates from live Bacillus anthracis, and it requires just four injections. Fewer steps in the manufacturing process mean less risk of residual toxins, said Kim Jung-soo, team leader of the company's Hwasun Plant, who led reporters through the anthrax facility during the tour.

Because human efficacy trials are ethically impossible, GC Biopharma turned to rabbit challenge studies, a method widely accepted under global biodefense guidelines. More than 90 percent of vaccinated rabbits survived anthrax exposure at six months, and all survived at 16 months.

Studies suggest rabbits are considered one of the most rigorous models for anthrax because they require high levels of antibodies to survive infection.

The facility is now producing doses for the national stockpile, with output expected to range between 150,000 and 300,000, according to GC Biopharma and KDCA officials. The final volume, they noted, will depend on future budget allocations and procurement plans.

A single 10-liter run of bulk substance yields about 100,000 doses. The anthrax production line, which was built in 2019 with 10.1 billion won (roughly $7.4 million) in government funding, occupies less than one-half of 1 percent of the 100,000-square-meter Hwasun campus.

The Division of Medical Stockpile Management at the KDCA confirmed with Korea Biomedical Review last Friday that “any anthrax vaccines stockpiled in the future will be domestically produced,” though the division spokesperson declined to comment further. 

The vaccine will not be sold commercially. It is intended as a strategic reserve for soldiers, first responders, and laboratory personnel in the event of a bioterror attack or outbreak through livestock. Korea has not recorded a domestic anthrax case since 2000, but officials point to recent outbreaks in Thailand, Uganda, and Zambia as evidence that the threat persists.

The rationale, as officials put it, is not economic. Kim Gab-jung, who heads the KDCA’s biothreat-response division, described the effort as a "form of national insurance" -- an investment the government hopes never to deploy. 

Lee, the development chief, was more blunt. Any company making vaccines, he said, has a responsibility to put public interest before profit. If it can’t, “it probably should not be in vaccines at all.”

At the briefing, Chung Yoon-seok, director of the KDCA’s Division of High-Risk Pathogens, echoed the sentiment. Even unused, he said, a homegrown stockpile remains a “national asset, even without direct financial gain.”

Will it travel?

GC exports more than half its flu vaccine and nearly ninety percent of its varicella doses, mostly to Southeast Asia and Latin America. Whether Barythrax will follow is unclear. 

Over lunch with reporters, Chung floated the possibility that Thailand, which has reported five anthrax cases and one death this year, “could be the vaccine's first stop.” Later, at the formal briefing, Kim clarified that no such plans were in place. “We can’t say for sure,” she said. “There are no export deals yet.”

Even without exports, Chung said the economics favored Korea. The cost of Barythrax, he estimated, was about one-seventh that of its U.S. counterpart, though he noted the figure was based on internal procurement data rather than public list prices.

Approval is only the midpoint. Follow-up studies will track how long immunity lasts and whether booster shots are needed. Additional trials will test protection against inhalational exposure, the deadliest form of the disease. Licenses are renewed every five years, Kim said, so "we must keep proving safety and durability."

The implications stretch beyond anthrax. GC says the platform used to develop Barythrax could accelerate the design of recombinant protein vaccines for other emerging pathogens.

“What we’ve built here will absolutely support future vaccines,” Kim said. “This development process helped us build a recombinant protein platform that can now be repurposed.”

And if the worst never comes?

“Of course we hope we never need to use it,” Kim said. “But needing it and not having it would be far worse.”