With major disease in seeming retreat, keep up measures against a comeback

The number of cases of tuberculosis, once called Japan’s “national disease,” has fallen to an all-time low. It is vital not only to continue analyzing the factors in detail, but also to remain vigilant against the disease so as to further contain its spread.

Last year, 11,519 people were diagnosed with TB in Japan. The number of new cases per 100,000 population stood at 9.2, dropping below 10 for the first time. That puts Japan in the category of “low-incidence countries” as described by the World Health Organization. At long last, Japan apparently is approaching the level of other developed countries.

TB is acquired by inhaling tubercle bacilli spread when a patient coughs or sneezes. It is believed that one to two out of every 10 people who become infected will develop the disease, but some people develop symptoms only decades later.

The recent drop in TB cases is believed to have been due to the effective measures taken against the novel coronavirus, such as improved ventilation and avoidance of the “Three Cs”: closed spaces, crowded places and close-contact settings. On the other hand, as more people were refraining from visiting medical institutions for fear of coronavirus infection, the possibility cannot be ruled out that some TB patients were overlooked.

Relevant organizations need to remain vigilant and carefully determine the actual situation.

TB became a serious epidemic in Japan beginning in the Meiji era (1868-1912), and more than 100,000 lives were lost to the disease every year until 1950, shortly after the end of World War II.

The number of TB patients fell sharply as a result of the spread of therapeutic drugs and the improvement of living standards, but it increased for a time in the 1990s. The main reason for this is that people who were infected with the disease during and after the war developed symptoms when their immune systems became weakened with advancing age.

In part due to public interest in TB waning as it became viewed as “an illness of the past,” the then health and welfare minister declared a state of emergency for TB in 1999, calling public attention to the disease.

Slightly more than 60% of new TB cases are still among those aged 70 or older. Despite the availability of therapeutic drugs, more than 1,800 people die of the disease each year, putting the elderly at high risk. If a cough or low-grade fever persists for more than two weeks, it is important to seek medical attention because of the possibility of TB.

In recent years, the number of TB patients from other countries has increased in Japan. Foreign patients account for 11% of Japan’s TB cases overall, and for more than 70% of cases among people in their 20s. To ensure that the language barrier does not delay their medical visits, the central and local governments should make efforts to provide information and medical assistance in foreign languages.

In Western countries with a low incidence of the disease, 60% to 70% of TB patients are of foreign origin. In some cases, people are required to be tested in advance if they arrive from countries with large numbers of TB patients.

In 2020, the Japanese government also established a system in which those who enter Japan from six countries with high TB incidence rates, including the Philippines and Vietnam, and who wish to stay in Japan for a medium or long period of time, are not allowed to enter unless they can prove that they are free of the disease.

However, the implementation of this system has been delayed due to the coronavirus pandemic. Now that immigration restrictions are being eased, urgent preparations should be made for the start of the system.

(From The Yomiuri Shimbun, Sept. 16, 2022)