What are the contraindications and precautions for influenza vaccination?

General contraindications for influenza vaccination include allergy to vaccine components, acute illness phase, uncontrolled severe chronic diseases, severely compromised immune function, and specific stages of pregnancy. Precautions typically include informing healthcare providers of your health status before vaccination, choosing a certified vaccination facility, monitoring post-vaccination reactions, receiving the vaccine at the optimal time, and consulting a doctor for special populations. Detailed analysis is as follows:

I. Contraindications

1. Allergy to vaccine components: Individuals who have previously had allergic reactions to components of the influenza vaccine (such as ovalbumin or formaldehyde), or who experienced severe reactions such as anaphylactic shock after vaccination, should not be vaccinated to avoid life-threatening risks.

2. Acute illness phase: Individuals currently experiencing acute conditions such as colds, fever, or acute gastroenteritis with body temperature ≥38.5°C or significant symptoms should postpone vaccination until fully recovered.

3. Uncontrolled severe chronic diseases: Patients with serious underlying conditions such as heart disease, chronic obstructive pulmonary disease (COPD), or diabetes that are uncontrolled or in an acutely exacerbated state should not be vaccinated to prevent worsening of their baseline condition.

4. Severely compromised immune function: Individuals with weakened immunity due to cancer chemotherapy, long-term use of immunosuppressive agents, or HIV/AIDS should not receive live attenuated influenza vaccines to avoid adverse reactions.

5. Specific stages of pregnancy: Live attenuated vaccines are generally unsuitable for pregnant women, especially during the first trimester. Vaccination decisions should be made based on vaccine type and gestational stage in consultation with a physician.

II. Precautions

1. Disclose health status before vaccination: Inform healthcare providers of any history of allergies, underlying medical conditions, and current medications to ensure proper assessment of vaccine suitability and avoid overlooking contraindications.

2. Choose a正规 vaccination facility: Receive vaccination at certified medical institutions such as hospitals or community health centers to ensure vaccines are properly sourced, stored, and administered, avoiding substandard products.

3. Monitor post-vaccination reactions: Remain at the vaccination site for 30 minutes after injection to observe for possible reactions such as dizziness, nausea, or local redness, swelling, and pain. Seek immediate care if adverse symptoms occur.

4. Optimize timing of vaccination: Get vaccinated between September and November, before the peak flu season, to allow sufficient time for antibody development and provide protection against influenza virus infection.

5. Consult a doctor for special populations: Elderly individuals, infants, breastfeeding women, and others with special health considerations should consult a physician before vaccination to determine the most appropriate vaccine type and schedule for safety.

After vaccination, keep the injection site clean and dry, and avoid bathing within 24 hours to prevent infection. Seek medical attention promptly if unusual reactions such as persistent fever or severe rashes occur. The protective effect of the vaccine lasts approximately 6–8 months; annual vaccination tailored to circulating virus strains is recommended to maintain effective immunity.