Flu Vaccination Effectiveness
I cannot provide specific effectiveness data for the current flu season in your state, as the evidence provided contains historical data from past seasons (1994-2024), not real-time surveillance data for the current year.
What We Know About Flu Vaccine Effectiveness Generally
Flu vaccine effectiveness varies substantially by season, age group, and how well the vaccine matches circulating strains, but when well-matched, it prevents 70-90% of influenza illness in healthy adults under 65 years and significantly reduces severe outcomes including hospitalization and death across all age groups. 1
Effectiveness by Age Group (When Vaccine is Well-Matched)
Healthy Adults (<65 years):
- 70-90% effective at preventing influenza illness 1
- Reduces work absenteeism by 32-45% 1, 2
- Decreases physician visits by 34-44% 1
Children and Adolescents (6 months-17 years):
- Recent data (2023-24 season) showed 59-67% effectiveness against outpatient visits 3
- 52-61% effectiveness against hospitalization 3
- Reduces influenza-associated otitis media by approximately 30% 1, 2
Elderly Persons (≥65 years):
- 30-70% effective at preventing hospitalization for pneumonia and influenza in community-dwelling elderly 1
- Among nursing home residents: 30-40% effective at preventing influenza illness, but 50-60% effective at preventing hospitalization/pneumonia and 80% effective at preventing death 1, 2
Effectiveness Against Severe Outcomes (Most Important for Mortality/Morbidity)
The vaccine's greatest benefit is preventing severe disease, even when effectiveness against mild illness is modest:
- 42% reduction in influenza-associated hospitalization overall (pooled data from 165 studies) 4
- 36% reduction in death 4
- 51% reduction in pneumonia 4
- 52% reduction in ICU admission 4
- 55% reduction in need for ventilatory support 4
Factors That Affect Effectiveness
Vaccine-Strain Match:
- Effectiveness is highest when vaccine strains match circulating viruses 1
- In mismatched seasons, effectiveness can be substantially lower (e.g., 2021-22 season showed only 16% effectiveness against A(H3N2), which was not statistically significant) 5
Virus Type:
- Generally higher effectiveness against influenza A(H1N1) and B viruses compared to A(H3N2) 3, 4
- 2023-24 data: VE against influenza B was 64-89% in children and 60-78% in adults 3
Vaccine Type:
- Quadrivalent vaccines show slightly higher effectiveness (45%) compared to trivalent (36%) against hospitalization 4
Critical Clinical Implications
Despite year-to-year variation in effectiveness, vaccination remains the single most effective measure for reducing influenza-related mortality and morbidity. 2
Common Pitfalls to Avoid
- Don't wait for "perfect" timing or current-season effectiveness data before vaccinating—influenza activity is unpredictable and vaccine effectiveness remains greater than zero for at least 5-6 months 6, 2
- Don't skip vaccination in low-effectiveness years—even modest effectiveness against mild illness translates to substantial protection against severe outcomes, hospitalization, and death 4, 5
- Don't delay vaccination for minor illnesses—only acute febrile illness requires deferral until symptoms abate; minor illnesses with or without fever are not contraindications 6, 2
Where to Find Current-Season Data
For real-time effectiveness data specific to the current flu season in your state:
- Check CDC's weekly FluView reports and interim VE estimates (typically published mid-season)
- Contact your state health department for local surveillance data
- Monitor CDC's seasonal flu vaccine effectiveness page for updated estimates
The key message: Get vaccinated regardless of predicted effectiveness, as the vaccine consistently reduces severe outcomes, hospitalization, and death across all seasons. 2, 4