With the outbreak of influenza virus in winter, human beings are once again facing the double threat of influenza virus and COVID-19. A few days ago, the Israeli Times reported that a pregnant woman in the country was found to be infected with both new crown and influenza virus, which is the first "co infection" case in Israel. However, the media specially pointed out that "some reports said that this was the first case of such double infection in the world, but as early as the spring of 2020, there were reports of common patients with influenza and new crown in the United States". From a global perspective, this is not the first time that COVID-19 and influenza viruses have joined hands in "committing a crime". In October 2020, Mexico confirmed the first case of simultaneous infection of COVID-19 and seasonal influenza in the country. In late February 2020, a man with severe cough and fever appeared in the hospital in New York. His nasal swab test showed that he was positive for influenza. Then, he was diagnosed with Xinguan and influenza at the same time, and his family also "got caught". "The clinical manifestations of COVID-19 infection are similar to influenza and viral pneumonia. Many symptoms are similar, such as fever, dry cough, chest tightness, chest pain. Even if some patients with COVID-19 have smell and taste disorders, the incidence rate is very low, so it is difficult for patients to distinguish whether the infection is new or flu, or whether they are infected with two viruses at the same time." Pan Chun, chief physician of the Department of critical medicine of Zhongda Hospital Affiliated to Southeast University, who was a member of the expert group of the national health commission when fighting the epidemic in Wuhan, told Science and technology daily. According to Bao Chuanjun, director of the Institute of acute infectious disease prevention and control of Jiangsu CDC, it remains to be seen whether CO infection with these two viruses will bring more serious diseases. "From the global public reports, there are few cases of simultaneous infection with two viruses, so it is difficult to judge what disease risks co infection will bring to the human body because of the lack of sufficient cases and data support." However, from the current literature, infection with COVID-19 and influenza viruses is not conducive to the development of the disease. A study of 307 novel coronavirus pneumonia patients published by the Research Institute of respiratory diseases, Tongji Hospital, Tongji Medical College, Key Laboratory of environmental health and Health Laboratory of Huazhong University of Science and Technology, School of medicine, Huazhong University of Science and Technology, 2020, found that patients with COVID-19 and B influenza infection had higher risk of adverse outcomes. Add fuel to the flames of two viruses co infected by Professor Xu Ke and Professor LAN Ke's research group, Wuhan University. The influenza virus can significantly promote COVID-19 infection in February 2021. Through the construction of influenza virus and COVID-19 co infected mouse model, the team found that the two viruses co infected in mice caused more serious diseases. In COVID-19 receptor ACE2 transgenic mice, influenza co infection with COVID-19 can cause more severe lung pathological damage and higher COVID-19 load. "If two viruses are combined, it may be more difficult to treat. On the one hand, because the target organs of influenza virus and COVID-19 are mainly respiratory system, once combined infection, the respiratory system damage may be more serious. On the other hand, the respiratory system damage also depends on viral load. The higher the viral load, the more serious the lung injury is. ”Pan Chun said. Every year, winter and spring are the high season of influenza. Recently, Shaanxi, Zhejiang, Henan and other places in China have rebounded in. Facing the double risks, how should we protect and protect ourselves and our families? "Vaccination is an effective means to prevent influenza and new crowns, especially the whole process of vaccination. At the same time, pay attention to hand hygiene, indoor ventilation, try not to gather in crowded places, and wear masks when traveling." Bao said. He also suggested that the immunity of the elderly and the special population is low, and the risk of influenza and COVID-19 is relatively large. Vaccination will reduce the incidence of severe diseases. "If you have symptoms of fever and cough, you can first check if you have any recent exposure history of COVID-19, such as whether you have contact with recent arrivals, and whether you have access to imported frozen foods or articles." Bao Jianjun reminded. "If there is no symptoms, if you have visited COVID-19 high-risk areas or have a close contact with new crown infections, you should not let down your mind immediately. You need to go to the nearest organization for nucleic acid testing immediately." Pan Chun suggested. (outlook new era)