Recently, the incidence of pertussis has been on the rise. Among them, the incidence rate of adolescents and adults increased significantly. This disease, which was previously thought to only affect infants and young children, is gradually becoming more advanced in age. According to data from the National Bureau of Disease Control and Prevention, a total of 15245 cases of pertussis were reported nationwide (excluding Hong Kong, Macao Special Administrative Region, and Taiwan) in January this year, with 5 deaths; 17105 cases of pertussis were reported in February, including 8 deaths. What is pertussis? Pertussis is an acute respiratory infectious disease caused by Bordetella pertussis, and is a legally reported Class B infectious disease. The disease has a long course, and typical cases can manifest as persistent cough for 2-3 months, hence it is called pertussis. The early symptoms of pertussis are similar to those of a common cold. In the first 1-2 weeks, there may only be symptoms of upper respiratory tract infections such as runny nose and cough. However, during this period, it is highly contagious and easily overlooked. The second to sixth week after that enters the spasmodic cough period, which is the most typical time for disease symptoms, often accompanied by intense and persistent spasmodic coughing at night, and the typical "crowing like echo" at the end of the cough may appear. The final recovery period from the disease still takes 2-3 weeks, and the entire course of the disease is very challenging. Infant cases, those with a history of vaccination or pertussis, often have atypical symptoms after infection. Among them, infant cases without typical spasmodic cough after infection are prone to cyanosis, shortness of breath, respiratory pauses, and even suffocation. If these related symptoms occur, timely medical examination should be sought to avoid delaying treatment. Who is prone to whooping cough? Pertussis is mainly transmitted through droplets. Infected individuals are the main source of infection, and for infants and young children, parents or other cohabitants infected with pertussis are the main source of infection. Pertussis can be seen in all age groups, with infants and young children without a history of immunity having a higher risk of developing the disease. The younger the patient is, the higher the risk of complications and severe illness, and in severe cases, even death. In countries where vaccines are widely used, more and more cases of pertussis are being found in older children and adults. Why is pertussis so aggressive? In recent years, there has been a resurgence of pertussis in developed countries such as Europe and America. For example, in 2004, 2005, 2010, 2012, and 2014, the United States had several large-scale whooping cough outbreaks, of which the incidence rate during the whooping cough epidemic in Washington State in 2012 was as high as 37.5/100000, 13 times higher than the previous year. Canada, Australia, New Zealand, Japan and other countries have also reported a surge in the incidence of pertussis. The incidence of pertussis in China has also shown an upward trend after maintaining a low level for decades. Official data shows that in 2017, the number of reported cases of pertussis nationwide began to exceed 10000, and then rose to a higher level every year. In 2018, there were over 20000 cases, and in 2019, there were over 30000 cases. The COVID-19 has fallen back, and 15798 cases were reported from 2020 to 2022. Dou Zhifang, deputy director and chief physician of the Department of Respiratory and Critical Care Medicine of the Aviation General Hospital, believes that there are two main reasons for the increase in the incidence rate of whooping cough. One is the insufficient persistence of vaccine immune efficacy. The human body can acquire resistance to pertussis through natural infection or vaccination