Pertussis is an acute respiratory infectious disease caused by Bauterus pertussis, which is often manifested as repeated and severe cough. In my country, it is listed as one of the 27 types of Class B infectious disease .
Recently, a reporter from First Financial learned from the 3rd Pertus Cough International Forum in 2021 that in recent years, the incidence of pertus cough in my country has gradually increased, and it is characterized by a low-age disease. Many experts are calling for strengthening pertussis monitoring and optimizing pertussis vaccination strategies.
Pertussis reappears
As an ancient infectious disease, whooping cough is extremely contagious and was one of the important causes of infant death worldwide before the vaccine was released.
Infectious Disease Department, Deng Jiqiu, director of the Department of Infection of Shenzhen Children's Hospital, said in an interview with First Financial News and other media that since my country included the pertussis vaccine in the immunization program since 1978, the incidence of pertussis has shown a sharp decline in the past 30 years from 1985 to 2014. The number of cases reported nationwide is below 3,000, which is at a very low level. However, since 2015, the incidence rate has shown an upward trend. The number of cases reported that year was more than 6,000, and by 2019, it has reached more than 30,000.
Professor Yang Yonghong said that those whooping cough usually occurs in spring and summer, but our country has a vast territory and different climates in different places, so those whooping cough cases are present all year round, and the epidemic occurs every 2-5 years.
shows the characteristics of younger age among those cough reported in my country. "Infants under 3 months of age account for the highest proportion of those whooping cough under 10 years of age. Among them, among those whooping cough cases with a confirmed history of immunization, 42.81% of those under 10 years of age are under 3 months of age; those who have not received vaccines containing anti-pertus cough components account for 58.20% of those under 10 years of age. Young infants have a higher risk of death from those whooping cough, and children with 3 months of age of age are prone to severe pneumonia, respiratory failure, lung consolidation, encephalopathy and other complications." Yang Yonghong said.
The phenomenon of re-rising incidence of pertussis is not uncommon in other countries, especially since the 1980s, in countries with high vaccine coverage such as the United States, Canada, and Australia, the incidence of this disease has once again shown an upward trend after maintaining a long-term low level, and some regions even had an outbreak of epidemics. This situation is called "reappearance of pertussis" internationally.
In the forum, many experts said that the reason for the recurrence of pertussis may be related to factors such as the increase in detection rate of , genetic changes in bautes pertussis, natural infection and gradual decline in protective immunity after vaccination. Among them, the conversion of pertussis vaccination from whole-cell vaccine to cell-free vaccine may also be a factor.
There are currently two main types of pertussis vaccines. One is a whole-cell vaccine made based on inactivated pertussis Bauterus, and the other is a cell-free vaccine made based on highly purified selective bacterial antigens.
Deng Jiqiu said that the whole-cell vaccine has slightly better immunization effect, but the side effects are relatively large after vaccination. About 2007, my country has gradually changed from being vaccinated with whole-cell vaccine to being vaccinated with a cell-free vaccine, based on the recommendations of the WHO and foreign experience. Although the resistance of acellular vaccine is slightly weaker than that of whole-cell vaccines, it produces fewer side effects. By 2013, my country completed the replacement of whole-cell vaccines. "Although the reappearance of whooping cough is related to vaccine conversion, it is more related to pediatricians' enhanced cognition of the disease and the improvement of laboratory diagnostic capabilities."
First Financial reporter learned in an interview that in the past, some cases of whooping cough infection were easily missed due to their lack of obvious symptoms.
vaccination strategy How to optimize
vaccination with pertussis vaccine is still a powerful weapon to resist the disease.
"From the cases we have observed in clinical practice, the disease has become severely increased by not receiving the pertussis vaccine. Although vaccination with the pertussis vaccine cannot completely prevent the onset of the disease, it can reduce the occurrence of many severe deaths." Deng Jiqiu said.
Currently, the immunization procedures for vaccines containing pertussis in my country are 1 dose of cellular vaccines in March, April and 5 months of age, 1 dose of cellular vaccine was strengthened at 18-24 months of age, and 1 dose of diphtheria tetanus combined vaccine was strengthened at 6 years of age.
In the forum, many experts suggested that my country's whooping cough vaccination strategy should still be optimized.
"Some babies are already ill before three months of age, so those whooping cough vaccination should be as early as possible. We recommend that the first dose of vaccination be advanced from the original 3 months to 2 months or even 6 weeks of age." Deng Jiqiu said.
Among the vaccines approved in my country, such as the children's pentacle vaccine, it can be used for vaccination of infants and young children over 2 months of age and containing pertussis ingredients.
In addition, according to a reporter from the First Financial Daily, 194 countries or regions around the world have taken the first dose of vaccination at 2 months (including 2 months of age).
Yang Yonghong said that the current transmission model of whooping cough has changed from the "child to children" model before vaccination to the "adult to infant" transmission model in the era of immunization planning. The increase in cases of pertussis among adolescents and adults has also become an important source of infection with pertussis in infants and young children.
Regarding the current prevention and control strategies of pertussis, Yang Yonghong believes that in addition to in vitro protection of infants of young-month age, he also recommends that children of appropriate age receive the "tetanus and dysfunction" vaccine when they receive the "tetanus and dysfunction" vaccine (the vaccines for diphtheria and tetanus are 6 years old), plus a cell-available pertussis vaccine; in addition, he also recommends that 12-year-old children receive another pertussis vaccine. In addition, he also recommended that pregnant women, medical staff and others receive the pertussis vaccine.
"This appeal is determined based on the relatively low production level of vaccine antibodies for acellular pertussis, short maintenance time, and will drop to the level of prone to disease in about five or six years. Therefore, it is necessary to receive a booster injection when the age of six and twelve years old. In addition, adult pregnant women, medical staff, and surrounding people who come into contact with children also need to receive a pertussis vaccine to form the so-called 'cocoon program', which can prevent newborns from being infected." Yang Yonghong said.
