The first stream has not left, and the second stream has arrived again. The influenza monitoring data recently released by the National Influenza Center shows that the proportion of H3N2 strains of H1N1 that previously dominated transmission has significantly decreased, but the proportion of H1N1 strains has increased significantly, with the proportion of H1N1 strains in the north reaching as high as 47.3%. From the recent reception situation of respiratory outpatient clinics, there is indeed a trend of declining H1N1 and increasing H1N1. During the period of overlapping attacks of influenza viruses, people should pay more attention to daily prevention. At the same time, when suspected flu symptoms appear, they should seek medical attention in a timely manner according to the type of virus for diagnosis and treatment. It is not recommended to purchase or take medication on their own when the condition is unknown, and they should not avoid seeking medical attention and wait for self recovery. Influenza is an acute respiratory infectious disease caused by influenza virus. Influenza viruses are divided into four types: A, B, C, and D, which have many differences in genome structure, peptide composition, infectivity, and pathogenicity. Among them, only influenza A and B viruses can cause important clinical diseases and seasonal epidemics in humans. Currently, the main infections in humans are H1N1 and H3N2 subtypes of influenza A virus and Victoria and Yamagata strains of influenza B virus. Recently, on social media, many people have shared their feelings about their illness, such as "Yi Liu is the king of kings, with pain in every bone seam" and "Jia Liu has a high fever for several days, with a splitting headache". In fact, based on medical experience, the symptoms caused by H1N1 and H1N1 are quite similar and difficult to distinguish from each other. It is necessary to cooperate with relevant laboratory tests to assist in diagnosis. Therefore, it is recommended that everyone should not make judgments solely based on their senses, but seek medical attention to make a clear diagnosis. Both influenza A and influenza B viruses initiate infection by binding to sialic acid receptors on the surface of respiratory epithelial cells through hemagglutinin. Influenza viruses enter host cells through endocytosis, undergo transcription and replication, and can trigger cytokine storms, leading to infectious poisoning. Patients and latent carriers are the main sources of infection, and they are contagious from the end of the incubation period to the acute phase. The incubation period is generally 1-7 days, mostly 2-4 days. Compared to others, influenza A is more likely to cause widespread outbreaks, has stronger infectivity, and the condition will be more severe; And the onset of COVID-19 is acute (with a short incubation period), the symptoms change quickly, the body temperature rises rapidly, and some patients may also exhibit gastrointestinal symptoms. H1N1 and H1N1 are relatively similar, both presenting with general symptoms of influenza, mainly characterized by fever, headache, muscle pain, and systemic discomfort. The body temperature can reach 39 ℃ -40 ℃. At the same time, patients may also have chills and chills, often accompanied by symptoms such as muscle and joint soreness, fatigue, and decreased appetite throughout the body. They often have sore throat, dry cough, as well as nasal congestion, runny nose, discomfort behind the sternum, facial flushing, and conjunctival congestion. Some patients have mild or asymptomatic symptoms. Children, as a special group, usually have higher fever levels when infected with influenza than adults. Gastrointestinal symptoms such as nausea, vomiting, and diarrhea are more common when suffering from COVID-19 than in adults. Newborns may only exhibit symptoms such as drowsiness, refusal to breastfeed, and apnea. Some influenza patients may experience complications, with pneumonia being the most common complication, as the influenza virus can invade the lower respiratory tract and cause primary viral pneumonia.