Treating latent TB in rural China

According to the latest statistical data, 833,000 people in China contracted tuberculosis in 2019, and more than 3,300 died from it. The prevalence of latent tuberculosis infection (LTBI) is known to be the greatest contributor towards spreading the disease, meaning that identification plays a key role in curbing and curing TB. But, to reach the global goal set by the World Health Organization (WHO) to eliminate tuberculosis by 2035, progress is still too slow.

Dr. Gao Lei is considered one of China's leading tuberculosis researchers. With his office based in the Institute of Pathogen Biology at the prestigious Chinese Academy of Medical Sciences in Beijing, he and his team are working tirelessly to combat TB. The campus is situated southwest of the Chinese capital amongst growing modern construction, but Gao mainly spends long stretches of time away to conquer the disease on the “front lines”: The battle against TB is fought mostly in rural areas, where 90% of cases happen and the medical infrastructure is outdated.

On the road to find a cure

Gao is a friendly man who has dedicated his life to his work. The scientist is on the road most of the year, at academic conferences or meetings with political decision-makers, but, above all, he is in the field. "I've been researching latent tuberculosis for a good 10 years, and I haven't really had any time for myself, besides work. Many foreign experts can hardly understand why my team and I work so hard," Gao says with a smile.

He grew up in a small town in the east coast province of Shandong. As a student, he enrolled in veterinary medicine, later switching to molecular biology. "However, I always found basic research boring, because the scientific questions were too far removed from the real needs of the population," Gao admits. After a research stay as a doctoral student at the Heidelberg Cancer Research Center in Germany, he decided to turn his attention to fighting the deadliest of all infectious diseases in China.

Before sunrise every morning, even on weekends and holidays, Gao and his team of 10 head to agricultural provinces in remote parts of the country. "Our study participants usually start work at seven o'clock. And before they have their breakfast, we have to take blood samples and chest X-rays," Dr. Gao says. In total, the researchers examine more than 50,000 people, diagnosing around 10,000 tuberculosis infections. The longest Dr. Gao has spent in the field at one stretch was 16 months.

Better testing

In China, many children were vaccinated to protect against bone tuberculosis in the 1980s and 1990s. However, skin-based tuberculin tests generally produce false positives. "ELISpot-based tests have also been found to be inefficient," Gao notes. "Especially in rural areas, where we conduct our field studies, very few clinics have the necessary laboratory equipment to cultivate the cells to be tested overnight,” Dr. Gao says. "We need new technologies and methods to contain tuberculosis."

Gao relies on QIAGEN's QuantiFERON test to get reliable results: "The test is much easier for our lab technicians to use, we don't need complicated lab technology, and we can analyze up to 29 samples on a single sample plate." That helps them to work more efficiently, especially in epidemiological studies, when Gao and his team evaluate high numbers of samples. In 2015, researchers determined that in China fewer than 20% were infected. "This is a great success, which we also owe to QuantiFERON. The test gives us a much more realistic estimate of the number of infections and allows us to narrow down the number of those who need preventive treatment," says Dr. Gao.

But the fight against tuberculosis is far from won. In China's poorest provinces, the containment of tuberculosis still requires plenty of effort and innovative ideas: "For example, in a pilot project, we are training doctors in remote villages to treat patients with latent tuberculosis using a video app. In another project, we have chest X-rays analyzed by artificial intelligence." The biggest challenge to eradicating tuberculosis in China, however, is not technical, according to Gao: "Patients with microbiologically confirmed active TB need to be treated as inpatients, instead of at home as is currently the case. Isolated treatment would reduce the number of cases, not unlike COVID-19."