Experts analyze why the flu has arrived earlier this year, mainly due to H1N1, and Shanghai is facing a small peak of flu after the start of school
Since the beginning of the school year, almost a month has passed, and the flu season has arrived in response. According to national influenza monitoring data, in the 36th week of 2023, the positive rate of influenza virus testing in southern provinces slightly increased, with subtype A being the main subtype; Flu activity in northern provinces remains at a low level. A total of 6 influenza outbreaks have been reported nationwide.
Shanghai medical institutions have also shown a significant increase in influenza cases, with some pediatric medical institutions experiencing an increase of over 50% compared to before. Influenza outbreaks usually occur in winter and spring seasons. Why did the flu outbreak arrive in September this year? Is it necessary to get vaccinated against influenza after getting it? Jiefang Daily's Shangguan News reporter interviewed Zeng Mei, Deputy Director of the Department of Infectious Diseases at the Affiliated Pediatric Hospital of Fudan University, and Ma Xiaoying from the Immunization Planning Institute of the Municipal Center for Disease Control and Prevention, interpreting this to the public.
Why did the flu arrive earlier this year due to its high incidence in winter and spring
At the Affiliated Pediatric Hospital of Fudan University, the number of influenza cases reached a small peak after the start of the school year, with an increase of over 50%. Zeng Mei told reporters that there was a strong wave of influenza from February to April this year, followed by sporadic outbreaks. The number of cases began to increase in early August, and after the start of school in September, there was a small peak of the epidemic.
Why did the flu arrive earlier this year when it was more common in winter and spring in previous years? Experts explained that after the COVID-19 epidemic, people need to "repay their immune debt", which has led to two waves of high incidence of influenza throughout the year. Effective prevention and control during the epidemic have made the human body like a flower in a greenhouse, with little contact with external viruses and bacteria. But from a medical perspective, the human immune system is trained in the natural environment, and the immune capacity in the "greenhouse" decreases. The probability of contact with viruses and bacteria after the epidemic will increase, especially for groups such as children and the elderly with weaker resistance.
The reporter learned that the main population affected by this round of influenza is elementary school students, and the epidemic strain is A type H3N2, which is different from the H1N1 epidemic that occurred from February to April this year. "Throughout the past 4-5 years, there have been sporadic or short-term outbreaks of type A H3N2, with little 'cause for trouble', resulting in low levels of immunity to type A H3N2 among the population. In recent times, it has become the main epidemic strain," said Zeng Mei.
Vaccination remains the most effective preventive measure
How to prevent influenza? Vaccination is the most effective way. Dr. Ma Xiaoying from the Immunization Planning Institute of the Municipal Center for Disease Control and Prevention introduced that vaccination can reduce the incidence of influenza. Research has shown that vaccinating healthy adults with influenza vaccine can reduce 42% of flu like cases and 59% of laboratory confirmed flu cases. If vaccinated annually, the protective effect is better. Pregnant women receiving influenza vaccine can reduce influenza incidence by 44% to 65%, and pregnant women receiving influenza vaccine can reduce influenza incidence by 48% in infants under 6 months of age.
In addition, influenza vaccines can significantly reduce the incidence of influenza related severe illness and hospitalization. Among children and adolescents under the age of 17, influenza vaccines can reduce hospitalization by 53.3%, with a maximum reduction of 68.7%. Getting vaccinated against influenza during pregnancy can transmit antibodies to the fetus, reducing laboratory confirmed influenza related hospitalizations in infants under 6 months of age by 72%.
Getting children vaccinated against influenza is beneficial for both families and communities. Getting vaccinated against influenza in children can reduce 35% of student absenteeism, 25% of parental absenteeism, and 20% of family members' risk of contracting influenza. When the influenza vaccination rate in kindergartens or schools is high, the overall influenza incidence rate in the community will decline.
Do you still need to get vaccinated after getting the flu
Many parents are puzzled: Do children still need to be vaccinated after getting the flu? Zeng Mei suggested that even if you have had the flu, you should get vaccinated in a timely manner. Generally, different subtypes of influenza will alternate during the flu season, and vaccination can effectively cover different subtypes and provide protection. As for what symptoms should be treated promptly? Experts have clarified that patients with high fever accompanied by poor mental state, persistent high fever lasting for 3 days, fever accompanied by convulsions, fever accompanied by vomiting and headache, acute wheezing accompanied by shortness of breath, and acute laryngitis accompanied by respiratory distress should seek medical attention in a timely manner; In collective life, if the infected person's cohabitants experience flu like symptoms one after another, it is recommended to screen for influenza in a timely manner. If diagnosed, taking anti influenza drugs within 48 hours of onset is effective; It is not recommended to come to the hospital with low fever or common cold to avoid cross infection. You can first observe at home.
Which groups of people are recommended to receive timely vaccination? Ma Xiaoying's introduction: Priority is given to recommending timely vaccination for the following 8 key and high-risk populations: medical personnel; Participants and support personnel for large-scale events; Population gathering places such as elderly care institutions, long-term care institutions, welfare homes, etc; Teachers and students in daycare institutions and primary and secondary schools; Home elderly individuals aged 60 and above; Children aged 6 months to 5 years and their caregivers; Patients suffering from one or more chronic diseases; Pregnant women or women preparing for the flu season. Generally, antibodies with protective levels can be produced about 2 to 4 weeks after vaccination, and the protective effect can last for 6 to 8 months.
As for whether it is necessary to stock up on medication during the flu season, experts believe it is unnecessary. Taking medication as soon as there are flu like symptoms can lead to drug abuse and may also cause adverse reactions. It is recommended to test the antigen in the hospital or self test the antigen at home, make a clear diagnosis of influenza, and take medication as soon as possible. This can not only receive timely and reasonable treatment, but also save medical resources.
The medication and follow-up examination after myopia surgery are directly related to the recovery effect of the surgery. Experts such as Zhang Fengju have stated that postoperative medication must strictly follow the doctor's advice and not blindly increase or decrease the dosage. The time for re examination is generally one day, one week, one month, three months, six months, and one year after the surgery, and routine re examination at the hospital is required at these time points. After surgery, if there is eye trauma, sharp decline in vision, eye pain, elevated intraocular pressure, etc., timely medical attention should also be sought.
The approved influenza vaccines for marketing in our country include trivalent inactivated influenza vaccine, quadrivalent inactivated influenza vaccine, and trivalent attenuated live vaccine, which are produced and supplied by different manufacturers. IIV3 includes split vaccine and subunit vaccine, IIV4 is split vaccine, and LAIV3 is attenuated live vaccine.
The World Health Organization announced on February 24th this year that the trivalent influenza vaccine components for the 2023-2024 influenza season are: H1N1, H3N2 for type A, and Victoria strain for type B; The composition of the quadrivalent influenza vaccine is higher than that of the trivalent influenza vaccine in the B/Yamagata series. At present, the influenza vaccine in Shanghai is a non immunization program vaccine, and residents voluntarily receive it at their own expense.
