About Influenza A and Influenza B! Authoritative Answers are Here!

Immune response after contracting Influenza A Effective immune protection against Influenza B How to differentiate and identify Whether it is Influenza A virus or Influenza B virus? January 18 Deputy Director Qi Ying of the Infectious Disease Prevention and Control Institute of Shenyang Center for Disease Control and Prevention Answers to hot topics of concern to citizens Question: Will patients who have had Influenza A be infected with Influenza B again? Answer: According to recent influenza monitoring data in Shenyang, both Influenza A and Influenza B have been detected in January, with Influenza B being the main type. Monitoring data shows that the proportion of Influenza B virus in northern provinces of China has continuously risen to 57.7% in the past 5 weeks, and in southern provinces, it has risen to 36.8% in the past 3 weeks. In some provinces, the proportion of Influenza B virus has exceeded that of Influenza A virus. Influenza A and Influenza B viruses are differentiated based on the genetic and protein sequence characteristics of the virus. The seasonal influenza caused by them is difficult to distinguish in clinical symptoms. To differentiate and identify whether it is Influenza A or Influenza B virus, pathogen typing tests such as nucleic acid testing and antigen testing are needed. In the same influenza season, different types and subtypes of influenza viruses usually coexist, but with varying proportions. The immune response generated after contracting Influenza A does not provide effective immune protection against Influenza B. This means that even if one has had Influenza A during this epidemic season, there is still a possibility of being infected with Influenza B again. Currently, influenza vaccines include components of Influenza A H1N1 subtype, Influenza A H3N2 subtype, and Influenza B, and it is recommended for high-risk groups to get vaccinated early. Question: What are the symptoms of Influenza B? Answer: Influenza B is an infectious disease caused by the Influenza B virus. Unlike Influenza A virus, Influenza B virus does not distinguish subtypes. It is divided into Victoria lineage and Yamagata lineage based on the hemagglutinin (HA) gene. Currently, the main circulating type of Influenza B is the Victoria lineage. Influenza B is mainly spread through contact and droplet transmission, highly contagious, and mild cases often have a short course and are self-limiting. Some patients may require drug treatment, and the disease is mostly curable. In some cases, patients can recover without treatment, but if symptoms persist and worsen, attention should be paid to prevent pneumonia, heart damage, shock, etc. In addition, patients with Influenza B often have a sudden onset, with symptoms such as fever (body temperature can be as high as 39℃-40℃), headache, muscle soreness, and general fatigue. Muscle pain, sore throat, and hoarseness are more common symptoms in Influenza B patients compared to Influenza A patients. Respiratory symptoms such as dry throat, sore throat, and dry cough are milder. When children contract Influenza B, digestive symptoms such as nausea, vomiting, and diarrhea are more common than in adults. Question: How to prevent influenza? Answer: Strengthen physical exercise, enhance physical fitness, ensure adequate sleep, and improve self-resistance. Maintain good personal and environmental hygiene, wash hands frequently, use soap or hand sanitizer, and wash hands with running water immediately after contact with respiratory secretions (such as after sneezing). Key areas such as doorknobs and handrails should be cleaned and disinfected regularly. Adjust clothing according to weather changes, maintain indoor air circulation. Pay attention to balanced diet, eat nutritious and easily digestible food, drink plenty of water, and eat fruits. Ventilate indoor spaces regularly, open windows for ventilation 2-3 times a day, each time for 20-30 minutes, adjusting the opening time according to weather conditions. During the influenza season, try to avoid crowded places, and if necessary, wear masks. Monitor your health, and if you experience symptoms such as fever or cough, rest at home. Seek medical attention early if symptoms are severe. If a family member has influenza, try to avoid contact, especially when there are elderly people or individuals with chronic illnesses at home. Pay special attention to protection in such cases. Getting vaccinated against influenza is the most effective way to prevent it. Currently, influenza vaccines include components of Influenza A H1N1 subtype, Influenza A H3N2 subtype, and Influenza B. It is recommended for high-risk groups to get vaccinated early, significantly reducing the risk of influenza and serious complications. Health Tips from Liaoning Provincial Center for Disease Control and Prevention Influenza Season is High, Pay Attention to Influenza B

1. During the high season of influenza, how to distinguish between Influenza A and Influenza B? Influenza B and Influenza A both belong to influenza viruses, and the clinical symptoms of seasonal influenza caused by them are similar. Therefore, to differentiate and identify whether it is Influenza A or Influenza B virus, pathogen typing tests such as nucleic acid testing and antigen testing are needed. In addition, there are certain differences in infectivity and pathogenicity between the two. Influenza A is more prone to variation, leading to large-scale transmission and outbreaks, while Influenza B usually causes localized outbreaks.
2. How is the current situation and trend of influenza in our province? Influenza viruses can be divided into four types: A, B, C, and D. The main causes of seasonal influenza are Influenza A and Influenza B viruses. The composition of Influenza A and Influenza B viruses may change alternately during different periods of the same or different influenza seasons. Recent monitoring data shows that the proportion of Influenza B has risen in our province, while the proportion of Influenza A has decreased. However, Influenza A still occupies the dominant position, and both are showing a trend of simultaneous prevalence. It is not ruled out that the proportion of Influenza B may continue to increase in the later period and become the main type of prevalence.
3. For patients who have just had Influenza A, can they be infected with Influenza B again? In the same influenza season, different types and subtypes of influenza viruses usually coexist, but their proportions are different. If you have been infected with Influenza A and have generated an immune response, it does not mean that you are immune to Influenza B. In other words, even if you have had Influenza A during this epidemic season, you may still be infected with Influenza B again.
4. As the winter vacation and Spring Festival holiday approach, how to protect oneself? Influenza virus is mainly spread through respiratory droplets produced by sneezing and coughing of infected individuals, and it can also be transmitted directly or indirectly through mucous membranes such as the mouth, nose, and eyes. Personal protection can be carried out through the following points: (1) Pay attention to personal hygiene habits, wash hands frequently; cover your mouth and nose when coughing or sneezing, and do not spit anywhere. (2) Wear masks scientifically. When taking public transportation, going to crowded places, or seeking medical attention, wear masks according to needs. (3) Maintain air circulation. Open windows for ventilation 2-3 times a day, each time for more than 30 minutes. When opening windows for ventilation, pay attention to keeping warm. (4) Try to avoid going to crowded and polluted places.
5. How can we better care for and protect high-risk groups? It is recommended that high-risk groups get vaccinated against influenza early. The 3-valent and 4-valent influenza vaccines on the market this year both include components of the current Influenza A and Influenza B Bv lineage, so both vaccines are effective. In addition, maintaining a healthy lifestyle is also essential. Eat regular meals three times a day, with a reasonable proportion of staple food, vegetables and fruits, and poultry, fish, and meat. Exercise moderately, ensure sleep; quit smoking and limit alcohol; maintain a calm mindset, exercise reasonably, and enhance immune function. When abnormal symptoms such as fever and acute respiratory infections occur, pay close attention and take measures such as resting at home, taking medication, or seeking medical attention according to the situation. If the condition worsens or if there is a significant worsening of pre-existing diseases, seek medical attention immediately.