Recently, topics related to "A stream" have frequently appeared on the hot lists of social media, attracting widespread attention.
In Beijing, Shanghai and other places, some school students have fever, mainly caused by influenza A virus infection. Hebei, Anhui and other places have also monitored increased activity levels of influenza A.
When will this round of armor flow pass? Is it time to get vaccinated now?
What is the current situation of this round of armor?
Influenza is an acute respiratory infection caused by influenza virus infection. The difference between it and the common cold is that influenza often has a rapid onset and rapid progression, with obvious fever (up to 39~40 °C), accompanied by chills, muscle and joint pain, fatigue, loss of appetite and other systemic symptoms, and can also have vomiting and diarrhea.
Influenza viruses are divided into four types: A, B, C, and D, among which influenza A(H1N1), influenza A (H3N2) and influenza B are the three types that dominate influenza epidemics.
On March 2, the 741st "China Influenza Surveillance Weekly Report" released by the National Influenza Center showed that the positive rate of influenza virus in the past three weeks showed an upward trend, and it was 25.1% in the eighth week of 2023 (February 20-26).
Trends in influenza virus positivity rates in sentinel hospitals across the country (blue line)
Recently, the CDC in many places issued a document to introduce the situation of this round of influenza:
According to surveillance data from the Beijing Municipal Center for Disease Control and Prevention, the number of single-week influenza-like cases in the city at the end of February increased by 78% compared with the same period in 2019, with influenza A virus dominating, of which the H1N1 subtype accounted for 64%, the H3N2 subtype A accounted for 35%, and influenza B accounted for 1%.
The Zhejiang Provincial Center for Disease Control and Prevention said that the current epidemic in Zhejiang is mainly influenza A(H1N1). Since influenza A(H1N1) has not been circulating in the province for nearly three years, vaccination rates are low and the population is generally susceptible.
The Anhui Provincial Center for Disease Control and Prevention said that the activity level of influenza virus in Anhui Province has increased significantly recently, mainly H1N1 influenza, and caused many outbreaks in primary and secondary schools and childcare institutions.
Li Tong, chief physician of the Department of Infection of Beijing You'an Hospital affiliated to Capital Medical University, once said that in recent years, affected by the new crown epidemic, on the one hand, people's influenza vaccination rate has decreased; On the other hand, the lower rate of influenza infection has caused people to lose immunity to influenza, making it possible for influenza to spread faster this year.
When will this wave of armor pass?
When the peak of this round of influenza A passes, it is difficult to give a specific time node, but the epidemic of influenza A has certain rules to follow.
Li Tong has said that the trend of influenza A generally weakens in March and April. In the north there is usually only one popular season, from December of the previous year to March of the following year; But in the south, in addition to the winter-spring epidemic season, there may be a small epidemic in summer.
Li Qi, director of the Department of Infection Management and Disease Control at Peking University Shougang Hospital, said that a study on the prevalence of influenza A in different regions of mainland China showed that:
In northern provinces such as Shandong and Hebei north of 33° north latitude, the epidemic peak is in January ~ February every year;
In Guangdong, Guangxi and other southern provinces south of 27° north latitude, the peak is in April ~ June every year;
The area between the two latitudes, such as Jiangxi and Hubei, shows a "double peak" in January ~ February and June ~ August every year.
In short, influenza A often occurs in winter and spring, and there may also be a small epidemic in the southern summer. For influenza A, in general, prevention is greater than cure. Influenza vaccination is the most economical and effective means of preventing influenza.
Is it still time to get a flu shot?
Let's start with the answer - there is a certain preventive effect, but it is not as good as vaccination before the start of the flu season.
Li Tong once suggested that first consider getting the flu vaccine before the epidemic season, especially the elderly, children, and people with low immunity, and it is recommended to be vaccinated every year.
Cui Cang, deputy director of the Department of Infection Management and Disease Prevention and Control at Beijing You'an Hospital, said that effective antibodies can be produced in about two weeks after vaccination. If it is in the epidemic period of influenza A, timely vaccination can also achieve a certain preventive effect.
From October to March every year, it is the high season of influenza in the north. The production of antibodies takes a certain amount of time, and the protective effect will gradually decay after 6~8 months of inoculation. It is best to complete the influenza vaccination in October~November.
Key populations for vaccination include older adults with underlying medical conditions and children with weaker immune systems. In addition, vaccination is also recommended for people who need to travel frequently, or who need to work in crowded places for a long time.
So remind everyone that in October ~ November this year, high-risk groups remember to get vaccinated against influenza in time to prevent the epidemic of influenza in the coming year. Vaccination is available at vaccinated community health service centres, child vaccination sites, centers for disease control and prevention, or township health centers.
How to treat influenza?
Influenza A is a self-limiting disease, mild cases can generally heal on their own one week after the onset, and they should rest and sleep more after the onset of symptoms; Drinking plenty of water can help dilute mucus and help relieve nasal congestion; Supplement nutrition, try to eat more fruits and vegetables, one egg a day, a glass of milk; Fully ventilated, it is best to open the window for 20~30 minutes in the morning, noon and evening.
Elderly people and patients with chronic underlying diseases often have more severe symptoms and can develop viral pneumonia, so seek medical attention as soon as possible.
When to go to the hospital?
If there is a high fever that does not subside (such as more than 39 °C) for three or four days without improvement, signs of dehydration (oligouria, dark urine), severe cough with a large amount of sputum, dyspnea or chest pain, etc., should be seen promptly.
How to use medication symptomatically?
If the symptoms are unbearable or the condition is aggravated, the drug can be used rationally under the guidance of a doctor.
Antipyretic: commonly used drugs are acetaminophen, ibuprofen, loxoprofen, etc., you can choose one of them, take it according to the instructions and avoid the superposition of a variety of antipyretic drugs.
Sore throat: based on drinking more water, topical drugs can choose cipitidate chloride, huasu tablets, sipayi clear throat drop pills, etc.
Nasal congestion: It will gradually relieve itself, you can try saline nasal washing.
Cough and sputum: mild cough can not be treated, if there is more sputum or sputum is not easy to cough up, you can take acetylcysteine, ambroxol hydrochloride, eucalyptus capsules, etc. under the guidance of a doctor.
Body aches: analgesics such as acetaminophen or ibuprofen can be taken with meals.
Wang Linghang, chief physician of the Infectious Disease Diagnosis and Treatment and Research Center of Beijing Ditan Hospital, said that there are currently antiviral drugs specifically for influenza viruses, which can help patients shorten the course of the disease and improve symptoms, but they should be used under the guidance of doctors.
Prevent influenza, usually do a good job of protection, maintain good hygiene habits, such as covering your mouth and nose with a tissue when coughing and sneezing; wash your hands frequently; A balanced diet, moderate exercise, and adequate rest can help boost immunity.
Editor of this issue: Zheng Ronghua