Recently, mycoplasma infection and mycoplasma pneumonia have become high-frequency words in the mother circle. Three years after the COVID-19 epidemic, before the arrival of mycoplasma infection, children had experienced several rounds of infectious diseases, including influenza, syncytial virus infection, infectious diarrhea, herpetic angina, etc. Since the start of school in March this year, a considerable proportion of children have been diagnosed with "one illness per month". The large-scale prevalence of mycoplasma was ahead of schedule and spread widely during the COVID-19 epidemic. Because everyone wore masks, washed hands frequently, kept social distance, increased ventilation and more surface disinfection of objects, children's contact with other pathogens was reduced, and the incidence rate of viral and bacterial infections was reduced. However, everything has two sides, and a decrease in infection results in insufficient immune stimulation of pathogens to the human body, an increase in susceptible populations, and a decrease in group immunity. Many countries have significantly increased the incidence of respiratory syncytial virus and other pathogen infections after reducing the intensity and scale of group protection implementation. In this context, experts proposed the concept of immunization debt during COVID-19 (the above content is quoted from the first issue of the Chinese Journal of Practical Pediatrics, Vol. 38, January 2023, "Immune debt and its impact during the prevalence of children's novel coronavirus"). To put it simply, the children of COVID-19 in the past three years may get one by one diseases now. The flu has hit the head, now it's mycoplasma's turn. Mycoplasma is a prokaryotic microorganism that resembles bacteria but does not have a cell wall. It is situated between bacteria and viruses, smaller than bacteria and larger than viruses, and is the main pathogenic microorganism for respiratory infections. The common large-scale prevalence of Mycoplasma mostly occurs in November and December each year, and this year it has advanced to August and September, affecting a wider population. The condition of the children is more severe and the course of the disease is longer. Mycoplasma pneumonia has typical characteristics, and children should be alert to the following situations: 1. Severe irritating dry cough: Severe cough is a prominent symptom of this disease. Initially a dry cough, the cough is stubborn and intense, causing the child to cough uncontrollably and even affecting daytime activities and nighttime sleep. In the later stage, there is a lot of phlegm, and the cough is still severe. 2. Fever: High fever is common, and if left untreated, the fever often persists. There are also relatively few patients with low or even no fever. 3. Auscultation often fails to hear rales: Ordinary lung infection doctors can hear moist rales, but most cases of mycoplasma pneumonia cannot hear rales. The lung auscultation is highly inconsistent with clinical manifestations such as severe cough and high fever, making it one of the characteristics of this disease. Therefore, the diagnosis of mycoplasma pneumonia often requires chest X-ray to assist in the diagnosis. 4. Chest X-ray: Typical mycoplasma pneumonia often shows large shadows in the lungs. 5. Blood routine test: The blood routine test of Mycoplasma has no specific characteristics, unlike typical bacterial infections where the total number of white blood cells, neutrophils, and CRP are all increased, and it is not as normal as viral infections, often showing normal or high white blood cells, or one of the items of white blood cells, neutrophils, and CRP is relatively high. 6. Mycoplasma pneumoniae antibody test: A positive Mycoplasma antibody test can aid in diagnosis, but a negative test cannot be excluded. Moreover, Mycoplasma antibodies are often undetectable in the early stages of the disease, which is not very helpful for early diagnosis. The above are typical features of Mycoplasma pneumonia, but in reality, not all cases of Mycoplasma pneumonia