How long can vaccination prevent swine flu?

Feb 26, 2025 Source: Cainiu Health

Dr. Ren Yi

Introduction

For healthy adults with normal immune system function, the influenza A vaccine typically provides effective protection for at least six months. During this period, the antibody levels stimulated by the vaccine remain within a range capable of resisting viral invasion. The vaccine's protective effect will be more durable and effective when the virus strains included in the vaccine closely match the actual circulating virus strains.

　　"A flu" generally refers to influenza A. Vaccination usually protects against influenza A for 6-12 months, although the exact duration may vary.

　　For healthy adults with normally functioning immune systems, the influenza A vaccine typically provides effective protection for at least six months. During this time, the antibody levels stimulated by the vaccine remain within a range that can resist viral invasion. When the virus strains contained in the vaccine closely match the circulating virus strains, the vaccine's protective effect will be more prolonged and effective. In such cases, individuals can maintain higher immunity even several months after vaccination.

　　For individuals with strong immune systems who belong to susceptible populations, the vaccine's protection may last about 12 months. The recipient's lifestyle habits and whether they are exposed to infection sources can also affect the duration of vaccine protection. For example, poor personal hygiene and frequently visiting crowded places can increase the risk of contracting influenza A, thereby shortening the vaccine's protective period.

　　It is recommended to get vaccinated annually to ensure the preventive effectiveness of the vaccine. Maintaining good personal hygiene habits, such as frequent hand washing and wearing masks, are also effective preventive measures.

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Why is the H1N1 flu more severe in individuals who are otherwise healthier?

Under normal circumstances, "Jia Liu" refers to Influenza A. Having Influenza A does not necessarily mean that the healthier a person is, the more severe the illness will be. The severity of Influenza A is related to the patient's own immunity. For most healthy individuals with normal immune systems, their immune systems can effectively respond to the viral infection, thereby limiting the progression of the disease.

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Does a child with influenza A need to be isolated?

Under normal circumstances, "Jia Liu" (甲流) refers to Influenza A. Children infected with Influenza A need to be isolated. Influenza A is an acute respiratory infectious disease caused by the Influenza A virus. As a susceptible population, children have immature immune systems and relatively weaker resistance, making them more prone to infection and inflammatory responses.