Who should receive the flu vaccination and what are the recommended prevention and treatment options for influenza?

Influenza Vaccination Recommendations

Annual influenza vaccination is strongly recommended for all persons aged ≥6 months who do not have contraindications, with special emphasis on high-risk groups to reduce morbidity, mortality, and improve quality of life. 1

Priority Groups for Vaccination

High-Risk Individuals

• All children aged 6 months through 59 months 1
• All persons aged ≥50 years 1
• Persons with chronic medical conditions:
  • Pulmonary disorders (including asthma) 1, 2
  • Cardiovascular diseases (excluding isolated hypertension) 1
  • Renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus) 1
  • Immunocompromised individuals 1
  • Children and adolescents receiving long-term aspirin therapy (risk of Reye syndrome) 1
• Pregnant women during influenza season 1
• Residents of nursing homes and long-term care facilities 1
• American Indians/Alaska Natives 1
• Persons with extreme obesity (BMI ≥40) 1

Close Contacts of High-Risk Individuals

• Healthcare personnel in all settings 1
• Household contacts and caregivers of:
  • Children aged <5 years, especially <6 months (who cannot be vaccinated) 1
  • Adults aged ≥50 years 1
  • Persons with medical conditions that increase risk for severe influenza 1
• Employees of nursing homes and chronic-care facilities 2, 1

Timing of Vaccination

• Optimal timing is before the influenza season begins, ideally by the end of October 1
• Vaccination should continue throughout the entire influenza season, even after influenza activity has begun in the community 1
• For children 6 months through 8 years receiving influenza vaccine for the first time, two doses administered at least 4 weeks apart are recommended 1

Vaccine Types and Administration

• For persons ≥6 months, any age-appropriate influenza vaccine can be used 1
• Children 6 through 35 months may receive either a 0.25-mL or 0.5-mL dose of age-appropriate inactivated influenza vaccine (IIV) 1
• Children ≥36 months should receive a 0.5-mL dose 1
• Administer vaccine intramuscularly: deltoid muscle for adults and older children, anterolateral thigh for infants and young children 1

Contraindications and Precautions

• Absolute contraindications:
  • History of severe allergic reaction to previous influenza vaccination 2
  • For live attenuated influenza vaccine (LAIV): pregnancy, immunosuppression, children <2 years, children 2-4 years with history of wheezing or asthma 1
• Precautions:
  • Moderate or severe acute illness with or without fever 1
  • History of Guillain-Barré syndrome within 6 weeks of previous influenza vaccination 1

Antiviral Treatment and Prophylaxis

• Treatment should be initiated as early as possible for:

  • Any hospitalized patient with suspected or confirmed influenza 1
  • Patients with severe, complicated, or progressive illness 1
  • High-risk patients with influenza of any severity 1

• FDA-approved antivirals:

  • Oseltamivir: For treatment of acute influenza and prophylaxis 3
  • Zanamivir: For treatment of acute, uncomplicated influenza in patients ≥7 years who have been symptomatic for ≤2 days; prophylaxis in patients ≥5 years 4

Vaccine Effectiveness and Benefits

• Vaccine effectiveness varies by season, ranging from 16% (not statistically significant) in 2021-2022 5 to 70-90% when vaccine strains match circulating strains 6
• Even with reduced effectiveness, vaccination can prevent serious outcomes including hospitalization, ICU admission, and death 5
• Vaccination reduces pneumonia occurrence by 53%, hospitalization by 50%, and mortality by 68% 2
• Vaccine effectiveness among patients with high-risk conditions (41%) approaches that of patients without high-risk conditions (48%) 7

Implementation Strategies

• Use reminder systems and standing orders to improve vaccination coverage 2
• Develop vaccination programs in outpatient clinics, emergency departments, walk-in clinics, nursing homes, and dialysis centers 2
• Continue vaccination efforts throughout the entire influenza season 1

Common Pitfalls to Avoid

• Delaying vaccination: Don't wait for the peak of influenza season; vaccinate as soon as vaccine becomes available
• Missing revaccination opportunities: Annual vaccination is necessary even if the vaccine contains the same strains as the previous year 1
• Overlooking high-risk individuals: Ensure all eligible high-risk persons receive vaccination
• Neglecting healthcare worker vaccination: Healthcare personnel should be vaccinated to protect themselves and their patients 1
• Misconception that the vaccine causes influenza: The inactivated vaccine cannot cause influenza as it contains killed virus 6

Influenza vaccination remains the most effective strategy for preventing influenza and its complications. The benefits of vaccination extend beyond the individual to the community through reduced transmission and protection of vulnerable populations.