High incidence of influenza in summer for the first time after the outbreak of COVID-19 Donghongba has been very busy recently. The deputy chief physician of the Department of Pediatrics of Xiamen maternal and child health hospital, Fujian Province, told the reporter that in the past more than a month, the number of infants with fever due to influenza in the outpatient department of the hospital has increased significantly. "There was a long line from morning till night." Not only in Fujian Province, but also in Guangdong, Jiangxi, Guangxi and other provinces, the disease control departments have recently issued warnings that the recent influenza monitoring data show that it has entered the peak of influenza in summer, and the epidemic intensity has increased significantly compared with the same period in recent two years. "The same is true of our monitoring results. This is the first time that there has been a high incidence of influenza in summer since the outbreak of COVID-19." Wangdayan, director of the National Influenza Center, said that according to the report, the current concentrated outbreak of influenza in the south is mainly concentrated in schools and kindergartens. Therefore, the school should focus on the implementation of morning and afternoon inspection and other prevention and control measures. Before entering the school every day, students should focus on checking whether there is fever, abnormal body temperature, etc. if there is any abnormality, students should be immediately taken to the temporary isolation room of the school, and contact the medical institution under the jurisdiction as soon as possible to transfer to the hospital fever clinic. "In fact, before the outbreak of COVID-19, the southern provinces will also have a high incidence season of influenza in summer in most years." Wangdayan said that the COVID-19 has reduced the "sense of existence" of influenza. Therefore, this influenza epidemic in many southern provinces has made many people feel a little sudden. "According to the monitoring results, after the outbreak of COVID-19, the overall level of influenza activity in China did decline in 2020, at a low level, but it lasted only one year, and the level of influenza activity rose again in 2021. At the beginning of this year, both the north and the South experienced a peak of influenza in winter and spring, while the level of influenza activity in southern provinces has risen rapidly again since June." Wangdayan said that it is expected that the level of influenza activity in southern provinces will continue to rise in the near future, the number of provinces with active influenza will increase, and there will also be serious cases. "It is expected that the level of influenza activity will gradually drop after the middle and late July." Affected by multiple factors such as climate and environment, there is little possibility of high incidence of influenza in the north in the near future. "Seasonal influenza and COVID-19 have the same transmission mode and similar clinical characteristics, and their high-risk population, high disease burden population and medical resources are highly overlapped. Once the seasonal influenza rebounds and shows a high epidemic trend, it will not only cause huge health losses, but also interfere with the prevention and control of COVID-19, resulting in a run on medical resources." Donghongba said that the latest influenza monitoring weekly report released by the National Influenza Center on June 24 showed that influenza viruses in southern provinces of China were mainly a (H3N2) subtype influenza viruses recently, and no antigenicity, genetic characteristics and drug resistance mutations of recent epidemic strains were found. This means that the original antiviral drugs are still effective. "But the symptoms of COVID-19 and influenza can overlap, which will increase the difficulty of differential diagnosis to a certain extent." Wangdayan said that during the winter and spring of 2022-2023, it is expected that there may be a seasonal high incidence of influenza in both the north and the south of China. "In the face of this situation, the public, especially the elderly, children, medical personnel and other key groups, must be vaccinated against influenza as soon as possible." Influenza inactivated vaccine and newcrown inactivated vaccine can be inoculated at the same time "At present, the winter and spring influenza vaccines from 2022 to 2023 have been put on the market one after another. The time is earlier than that in previous years. The public can start to make an appointment for vaccination." Yuwenzhou, chief physician of the immunization planning center of the Chinese Center for Disease Control and prevention, said that China will supply trivalent and tetravalent influenza vaccines at the same time this year. The trivalent influenza vaccine includes three types of influenza A H1N1, H3N2 and B Victoria viruses. In addition, the tetravalent influenza vaccine also includes B Yamagata influenza viruses. Yangxiaoming, director of the national joint vaccine Engineering Technology Research Center, said in an interview with the media that at present, the Changchun Institute, Shanghai Institute and Wuhan Institute of Sinopharm have a total production capacity of nearly 70million doses of influenza vaccine, so as to do a good job in vaccine protection against seasonal influenza. Since October, 2021, all parts of the country have successively launched the enhanced immunization of novel coronavirus vaccine for key populations and the vaccination of people aged 3 to 11, and the vaccination of the elderly population is also continuing. This part of the population overlaps with the key and high-risk groups recommended for influenza vaccination. "We can promote the simultaneous vaccination of influenza inactivated vaccine and domestic new coronavirus inactivated vaccine." Yuwenzhou said that in this way, it can reduce the number of times for the recipients to and from the vaccination clinic. Especially for the elderly, it is convenient and helpful to improve the vaccination rate of two vaccines if they can be vaccinated at one time. At the same time, reducing the number of vaccination also reduces the pressure on vaccination clinics. So, in terms of security, is this feasible? Yu Wenzhou said that in previous documents, the World Health Organization recommended that the interval between the vaccination of the new crown vaccine and other vaccines should be 14 days, but the updated guidelines issued in October 2021 pointed out that the influenza inactivated vaccine and the new crown inactivated vaccine can be vaccinated at the same time. When the two vaccines are vaccinated at the same time, it is best to inject them separately in the opposite limb to minimize the risk. "At present, the policies of various countries are not unified regarding the vaccination interval between the new crown vaccine and other vaccines." Yuwenzhou said that the United States, Finland and other countries have made it clear that they can vaccinate Xinguan vaccine and other vaccines (including influenza vaccine) at the same time, but they should avoid vaccinating at the same place. France suggests that influenza vaccine and new coronal vaccine should be vaccinated at the same time, but requires that the vaccination of other types of vaccines should be at least 14 days away from the vaccination of new coronal vaccine. The technical guidelines for vaccination against novel coronavirus (the first edition) in China does not recommend that the new coronavirus vaccine be vaccinated at the same time as other vaccines, pointing out that the vaccination interval should be greater than 14 days. "However, with the passage of time, the latest scientific research results show that the simultaneous vaccination of domestic new coronal inactivated vaccine and influenza inactivated vaccine will not reduce the immunogenicity, nor increase adverse reactions. However, whether influenza inactivated vaccine and other technical routes of new coronal vaccine can be inoculated at the same time needs to be supplemented with scientific evidence." Yuwenzhou said that in the future, relevant departments may consider revising technical guidelines to provide policy basis for the elderly and children to be vaccinated with influenza inactivated vaccine and domestic newcrown inactivated vaccine at the same time. Three necessary conditions for influenza pandemic "In the winter and spring of 2022-2023, there may be a seasonal high incidence of influenza in the South and north of China, but the possibility of an influenza pandemic is very low." Wangdayan said that seasonal influenza is different from influenza pandemic, and the latter far exceeds the former in terms of scope of impact and destructive power. In 1918, the "Spanish influenza" that ravaged the world caused hundreds of millions of people to get sick and 25million people to die. In the more than 100 years since then, there have been four global influenza pandemics with clear epidemic evidence, causing tens of millions of deaths. "There are three prerequisites for an influenza pandemic." Wangdayan said, first of all, the influenza virus has mutated into a new virus through "reassembly"; Secondly, the virus can spread continuously and effectively among people; Finally, people generally lack immunity to it. When these three conditions are complete, the new virus can spread widely around the world in a short time (1-2 epidemic waves), resulting in a sharp increase in the number of patients, severe cases and deaths, a serious overload of the service capacity of the medical and health system, and an impact on the normal operation of the society. "Spanish pandemic influenza" was caused by influenza A (H1N1). At that time, it was a brand-new influenza virus. Since then, it has gradually evolved into the main strain causing seasonal influenza among people. Wangdayan frankly said that the pandemic will happen again, and science can not accurately predict the time. "The reason is that the influenza virus is changeable." Influenza viruses can be divided into four types: A, B, C and d according to their core proteins. Two subtypes of influenza A virus, H1N1 and H3N2, and influenza B virus (Yamagata strain and Victoria strain) can cause seasonal epidemics. Influenza C virus only sporadically infects. Influenza D virus mainly infects cattle and no human infection has been found. "We need to pay special attention to influenza A virus, which is very changeable." Wangdayan said that influenza viruses are RNA viruses. According to different combinations of hemagglutinin antigen (HA) and neuraminidase antigen (NA) on the surface of virus particles, influenza A viruses can be further divided into various subtypes, up to 198 in theory. More importantly, influenza A virus lacks the participation of RNA correcting enzymes in the replication process, which is prone to errors. Moreover, the characteristics of segmented genome make it easy for different subtypes of viruses to have gene rearrangement when they infect a host at the same time. "The point mutation of HA gene and NA gene in the replication process of influenza A virus leads to antigen drift, which can re infect previously immunized hosts, leading to repeated epidemics of influenza. This is also one of the important reasons why seasonal influenza vaccine should be vaccinated every year." Wangdayan said that due to the high frequency of variation in the replication process of influenza A virus, the probability of viral genome rearrangement and even new virus generation is also high. "Influenza viruses are constantly mutating, which means that the emergence of new viruses is only a matter of time. At present, it is difficult for humans to predict the exact time of the emergence of new viruses. Scientists around the world have been committed to capturing the road map of their mutation." In addition, influenza viruses that infect people often come from cross species transmission of other animals. They are distributed in the sea, land and air and have a wide range. "Every time the virus that causes an influenza pandemic is a new virus produced by the recombination of influenza viruses from different hosts." Wangdayan said, for example, the pathogens of the Asian influenza pandemic in 1957 and the Hong Kong influenza pandemic in 1968 were caused by the new pathogens after the reconstitution of the influenza virus and the avian influenza virus prevalent in the population at that time. The 2009 H1N1 influenza virus was also a reconstituted human swine avian influenza virus. As a mixer, pigs played a key role in the generation of new viruses. Relevant experts said that China is a large country of pig and poultry breeding, and the methods of free range and mixed breeding are very common. The mode of livestock and poultry concentrated in the wholesale market and then sold in the live poultry retail market, as well as the non-standard use of animal vaccines, have promoted the generation of new influenza viruses, and each cross species transmission of animal influenza viruses has provided opportunities for the generation of influenza pandemic strains. Therefore, in addition to strengthening the monitoring of human, swine and avian influenza viruses, the most fundamental thing is to promote the transformation and upgrading of China's livestock and poultry breeding industry, improve its biosafety management level, and realize the modernization of livestock and poultry breeding; At the same time, guide the public to establish a healthy consumption concept, and promote the centralized slaughter, killing of white birds or listing of frozen fresh birds; Research and develop new avian influenza vaccines that can prevent the infection and spread of the virus. Continuously enrich the "ammunition depot" for dealing with influenza pandemic Since an influenza pandemic is bound to occur, are we ready? "In fact, mankind is constantly trying to sum up experience from history and condense it into coping strategies for the next unpredictable but inevitable influenza pandemic." Wangdayan said. This is how the "guidelines for influenza pandemic preparedness and response" came into being. The plan, formulated by the World Health Organization in 1999, clearly points out that early rapid containment, rapid use of vaccines and drugs, a strong monitoring system and open and transparent information sharing are the key measures to deal with the influenza pandemic. China also formulated this guideline in 2005