Four rounds of screening for high incidence of pulmonary tuberculosis on campus can hardly prevent the spread of the epidemic

In March 2018, medical staff in Zaozhuang City, Shandong Province were explaining tuberculosis prevention and control knowledge to primary school students. In recent years, the incidence of pulmonary tuberculosis on campus has shown an upward trend. (ICphoto/figure)

22 students were suspended from school for treatment of pulmonary tuberculosis, 43 were screened for abnormal chest CT images... Until October 14, 2020, Jiangsu Normal University released the "Fact Sheet", more than 4000 students and teachers at school finally learned that the school found the case of students on August 21, 2019, and pulmonary tuberculosis has been spreading in the school for more than a year.

He Xiaoxin, deputy director of the Beijing Tuberculosis Control Institute, was not surprised to see the news at first. He, who has been engaged in the prevention and control of tuberculosis in schools for more than ten years, told the reporter of Southern Weekend that how to detect early, how to deal with early screening and preventive treatment, and how to report the epidemic situation in the light of the cluster epidemic situation on campus are all commonplace issues.

"Many people believe that tuberculosis (commonly known as" tuberculosis ") has disappeared, but in fact China is still the third country with high burden of tuberculosis disease in the world. From the incidence rate, there are about 6 tuberculosis patients per 10000 people every year. As a respiratory infectious disease, schools, which are densely populated places, are prone to the spread of tuberculosis. There are so many schools in the country, and the situation is different. Even if China issued the "School TB Prevention and Control Work Norms" in 2017, it is inevitable that there will be some cluster outbreaks. " He Xiaoxin said.

On the same day that Jiangsu Normal University released the Situation Statement, the World Health Organization also released the 2020 Global Tuberculosis Report. The report shows that there will be about 10 million new TB patients in the world in 2019, of which about 8.4% will come from China, second only to India and Indonesia. The report also mentioned that the current goal of "global elimination of TB by 2030" is too slow, and the prevalence of COVID-19 makes TB prevention and control even worse.

The outbreak of tuberculosis in Jiangsu Normal University and the news that Qingdao tuberculosis patients were infected with COVID-19 in hospital have pushed tuberculosis, the oldest respiratory infectious disease, to the forefront again.

On October 14, 2020, Jiangsu Normal University released a statement that 22 students in the Pan Anhu campus of the school's Science and Technology College were diagnosed with tuberculosis, and 43 were screened for chest CT imaging abnormalities. (People's vision/picture)

The school organized four rounds of screening

According to the Information Bulletin, in just 418 days from August 21, 2019 to October 12, 2020, 22 students in the Pan Anhu Campus of Science and Technology College (Independent College) of Jiangsu Normal University were successively diagnosed with tuberculosis.

A number of students studying in the campus told the Southern Weekend reporter that Class 1 of 2018 Software Engineering had become the "hardest hit area" of the epidemic. As early as 2018, some students in this class suffered from pulmonary tuberculosis. Later, every semester, some students dropped out of school, and about 10 students were diagnosed.

In the latest round of screening covering 4868 teachers and students in the school from September to October 2020, 43 students had abnormal chest CT images, which were observed separately. A student of the school said in an interview with Xinhua News Agency and other media that more than 20 of them came from the aforementioned classes. According to Xinhua News Agency, the time span has exceeded one year since the school received the first case notification.

Wu Yunxia, deputy director of the Center for Disease Control and Prevention of Jiawang District, Xuzhou, said in an interview with Xinhua News Agency that in the summer vacation of 2019, He XX, a student of the Institute of Science and Technology, was diagnosed with tuberculosis in Huai'an First People's Hospital in his hometown. The Center for Disease Control and Prevention of Jiawang District, where the Science and Technology Institute is located, informed the school after learning the news, and organized the first round of screening for 91 close contacts in two classes of the Software Institute where He is located, but no new cases were screened.

At the end of 2019, the school carried out the second and third rounds of screening, covering 1296 and 3450 people respectively, and found 7 new cases. From January to August 2020, the school did not open due to the COVID-19 epidemic, but 11 cases were reported from the students' source areas.

After the resumption of classes on September 1, the Center for Disease Control and Prevention of Jiawang District, Xuzhou City, received three more cases reported from the student origin, and the school immediately carried out the fourth round of screening, which was mentioned in the "Situation Statement". The school carried out tuberculin test screening (PPD) and chest X-ray examination for all teachers, students and logistics personnel from September 11 to 17, 2020.

"For the cases that are strongly positive in PPD screening, we will further carry out CT screening." On October 15, 2020, a staff member of the Tuberculosis Prevention and Control Department of Xuzhou Center for Disease Control and Prevention told the reporter of Southern Weekend by telephone that five or six disease control experts have gone to work in the school for many days. Due to the sensitivity of chest CT images, 43 students who were screened for abnormalities need to be isolated first, waiting for further diagnosis.

"PPD is mainly used to find the latent infected persons who have been infected with TB bacilli but have not yet become ill, but infection does not mean that they will get sick, and the incidence rate is only about 5% - 10%. Chest films and CT images are only auxiliary diagnostic means, and the final diagnosis depends on etiology, depending on the pathological results of sputum culture or lung biopsy, whether TB bacilli are found." Li Liang, vice president of Beijing Chest Hospital affiliated to Capital Medical University, introduced the role of several screening methods from a clinical perspective.

He Xiaoxin stressed that screening should also pay attention to quality and coverage to ensure that all patients and infected persons are found. He believes that the screening method of the school can basically find patients and latent infections.

The epidemic situation of tuberculosis on campus is on the rise

Although both are respiratory diseases, early detection, detection and prevention of pulmonary tuberculosis are much more difficult than COVID-19.

"COVID-19 has a clear incubation period. For example, if it does not become ill within two weeks after contact with patients, the probability of becoming ill will be very low in the future. However, there is no clear incubation period for TB, which may not be infected after contact, or may not become ill for life if infected, or it will become ill within a few months, a year, or even ten years." Li Liang said.

Zhang Qian (a pseudonym), a freshman of the university, told the reporter of Southern Weekend that after Jiangsu Normal University went on a hot search due to tuberculosis, the school asked the head teacher to hold an emergency class meeting. At present, the teaching on campus is still normal, but hand disinfectant will be placed on the podium, and classrooms with less than 90 people will no longer be equipped with amplification equipment and microphones.

In recent years, the outbreak of tuberculosis on campus has attracted public attention for many times, and the largest one occurred in 2017. In August of that year, a tuberculosis epidemic occurred in the Fourth Middle School of Taojiang County, Yiyang City, Hunan Province. As of November 24 of that year, 81 confirmed cases and 7 suspected cases had been found. In addition, 9 confirmed cases and 3 suspected cases were found in vocational secondary schools in Taojiang County. Several persons in charge of Taojiang County Health and Family Planning Bureau, Education Bureau and CDC were removed from their posts.

On October 15, 2020, the Emergency Notice on Further Strengthening the Prevention and Control of Tuberculosis in Schools (hereinafter referred to as the Notice) jointly issued by the Jiangsu Provincial Health Commission and the Jiangsu Provincial Department of Education showed that in 2020, two universities in the province, Yangzhou University and the Science and Technology College of Jiangsu Normal University, had a large number of TB clusters, and faced a grim situation.

In the Notice forwarded by the official website of the affiliated school of Jiangsu Normal University, it was mentioned that in 2019, the reported incidence of tuberculosis in Jiangsu Province was 306/100000, a decrease of 27.5% over 2015, but the epidemic situation of tuberculosis on campus was rising. The registered incidence of tuberculosis among students increased from 13.7/100000 in 2015 to 16.1/100000 in 2019, an increase of 17.5% in five years.

In addition, the cluster epidemic situation of tuberculosis on campus (the number of student patients is 3 or more) also has an upward trend. In 2015, Jiangsu Province reported a total of 22 cases of tuberculosis epidemic in schools, which rose to 52 in 2019, more than doubling. More than 80% of the TB epidemic in the province occurs in high schools and colleges.

At present, the routine tuberculosis screening in domestic schools is mainly carried out when freshmen enter the school for physical examination. The contact history is inquired and epidemiological investigation is carried out when they are under the age of 18. Chest films are taken only when they are over the age of 18. Some students may not be screened, or they may not get sick until a year or two after entering school.

He Xiaoxin believes that the crowded, relatively closed classroom and dormitory environment, the decline in immunity caused by academic pressure and irregular life on campus are all likely to be the reasons for the outbreak of the cluster epidemic. The symptoms of pulmonary tuberculosis are similar to those of other respiratory diseases cough, fever and expectoration, which increase the difficulty of early detection and timely diagnosis. In addition, some students did not seek medical treatment in time or were unwilling to suspend school, which further aggravated the difficulty of tuberculosis prevention and control in schools.

"Therefore, school doctors should be trained. If students have similar symptoms, they should think about doing tuberculosis screening in time. Schools should also spread knowledge about tuberculosis to students, exercise frequently, ventilate more, inform students and parents in time when patients are found, and do a good job of joint screening and prevention and control with the disease control department." Li Liang told the Southern Weekend reporter.

Low proportion of students taking preventive medicine

Generally, if ordinary tuberculosis patients receive formal treatment, the course of treatment will take 6-8 months; Without treatment, each patient can infect an average of 10-15 people a year. Once a student has been diagnosed, the school shall handle the suspension and resumption procedures for the student according to the relevant regulations and the certificate issued by the hospital.

According to the aforementioned Notice, after analyzing several cluster epidemics in Jiangsu Province, it was found that in the prevention and control of school tuberculosis in Jiangsu Province, there were problems such as inadequate implementation of screening for freshmen, substandard screening procedures for close contacts, and inadequate implementation of epidemic response measures.

"At present, the most serious weak link in our province is the low proportion of students with strong PPD only taking preventive medicine. The important reason for the two public health emergencies in colleges and universities this year was that students with strong PPD only refused to take preventive medicine." The Notice wrote.

Simple PPD is strongly positive, indicating that the body has been infected with tuberculosis bacteria, which may develop into tuberculosis, or may rely on their own resistance to control tuberculosis bacteria without disease. "The lifelong incidence of this kind of population is about 5% - 10%. Many students or parents have a fluke mentality and refuse to take preventive medicine, but they may develop into active tuberculosis at some time in the future, becoming a hidden danger of disease transmission." He Xiaoxin introduced.

Preventive treatment is the most effective and reliable means to reduce the number of secondary cases in the management of cluster epidemic. However, the preventive effect can only be achieved when the proportion of preventive medication taken by students with strong PPD positive is 70% - 80% or more. At present, the preventive treatment of tuberculosis infection in China follows the principle of informed consent.

"If only 30% of people take medicine, the epidemic will be difficult to control, and the occurrence of cases will continue. At this time, disease control and schools need to repeatedly publicize and mobilize, but there will still be students or parents who firmly disagree." He Xiaoxin said that if we can prevent and control the COVID-19 epidemic, qualified pure PPD strong positive must receive preventive treatment, the situation will be completely different.

Eliminating tuberculosis: promoting prevention is the key

The epidemic situation of pulmonary tuberculosis in Jiangsu Normal University exposed the problem of low compliance of preventive medication. Students or parents think that they do not need to take medicine if they do not get sick. The main reason is that they are worried about the side effects of drug treatment.

According to the requirements of the Notice of Jiangsu Province, schools with epidemic situation should bear the main responsibility and make sure that more than 90% of students with strong PPD positive take preventive medicine. If any student refuses to take medicine, the school must adopt online education and other forms of teaching to ensure that contact with other students is avoided during the observation period. However, the Notice is not binding.

At the 51st World Lung Health Conference held on October 20, 2020, "promoting prevention" became the annual theme of this year.

During the COVID-19 epidemic, many countries had problems such as patients' delay in seeking medical treatment and the decline of TB detection priority, which directly led to a sharp decline in the rate of patient detection.

"By the end of 2020, Xinguan and tuberculosis may lead to 1.5 million to 2 million deaths globally, and it is hard to say which disease will become the number one killer of infectious diseases this year." said Dr. Peter Sands, CEO of the Global Fund to Fight AIDS, Tuberculosis and Malaria.

In order to achieve the goal of "global elimination of tuberculosis by 2030", strengthening prevention becomes the key. The preventive treatment of tuberculosis means that people who have been infected with tuberculosis bacilli are given anti tuberculosis drugs. The Global Tuberculosis Report shows that the number of infected people receiving preventive treatment increased from 1 million in 2015 to 4.1 million in 2019.

Shannon Hader, Deputy Executive Director of UNAIDS, said that preventive treatment for people with dual infection of AIDS and tuberculosis has effectively reduced the risk of HIV carriers suffering from tuberculosis and death. The future plans to improve the goals, for example, to achieve greater and faster progress in preventive medication among children in active tuberculosis families.

"The COVID-19 epidemic has taught the public a popular science lesson about respiratory infectious diseases. Tuberculosis is terrible. If it can be found early, it can be prevented and treated; if it is found late, it may continue to spread and cause a cluster epidemic." He Xiaoxin believes that it is equally important to increase the publicity and education of tuberculosis prevention, strengthen management, and increase investment in prevention and control.

Southern Weekend reporter Cui Huiying Southern Weekend intern Dong Mengyuan