欧洲疾控中心-流感嗜血杆菌病-2023年度流行病学报告（英）-2025_11页_1mb

Summary of the Annual Epidemiological Report on Haemophilus influenzae Disease for 2023

Core Content

This report presents the epidemiological data on invasive Haemophilus influenzae disease (Hib) in the EU/EEA region for the year 2023. It highlights the resurgence of the disease, the role of vaccination in reducing Hib-related infections, and the evolving serotype landscape in the post-vaccination era.

Main Points

• Case Numbers and Rates:

  • A total of 5,234 confirmed cases of invasive Hib disease were reported in 2023, representing a continued increase from 2022 (3,983 cases) and a nearly tripling from the pandemic-era levels of 2020 (1,838) and 2021 (1,693).
  • The overall notification rate reached 1.2 cases per 100,000 population, the highest in the past five years.
  • The highest rates were observed in Denmark (2.3), Lithuania (2.1), and Sweden (2.1).

• Age and Gender Distribution:

  • Infants under one year had the highest notification rate (6.41 per 100,000), followed by those aged 65 and older (3.2).
  • A bimodal distribution was observed, with peaks in very young children and older adults.
  • Males had higher notification rates than females in most age groups, with the most pronounced difference in infants (7.3 vs 5.4 per 100,000).

• Seasonality and Trends:

  • The disease followed a more typical seasonal pattern in 2023, with a winter peak and summer decline.
  • The 12-month moving average showed a sustained increase in transmission.
  • Case numbers in 2023 were above the five-year average, particularly in the first quarter, and remained elevated throughout the year.

• Serotype Distribution:

  • Serotyping data were available for 60% of cases, with non-capsulated strains accounting for 81% of infections.
  • Serotype f was the most common capsulated strain (6%), followed by serotype b (5%).
  • Serotype b incidence declined slightly (5% in 2023 vs 9.1% in 2022), indicating the success of Hib vaccination programs.
  • The notification rate for non-capsulated strains increased annually, peaking in 2023.
  • The 'Other' serotypes group also showed an increasing trend, emphasizing the need for more detailed serotyping.

• Clinical Presentation:

  • Pneumonia (25%) and septicaemia (23%) were the most frequently reported clinical presentations.
  • Meningitis (13%) and epiglottitis (0.2%) were also reported, along with less common presentations like osteomyelitis and cellulitis.
  • 36% of cases were classified under 'other' clinical presentations, and 50% of cases had no clinical information available.

• Case Fatality Rate (CFR):

  • The CFR for all cases with known outcome was 8.6%.
  • The highest CFR was observed in serotype e (12.8%), followed by serotype b (8.2%) and non-capsulated strains (7.9%).
  • The majority of fatal cases occurred in individuals aged 65 and older (11.5% CFR), and unvaccinated individuals (10% CFR).

• Vaccination Status:

  • Vaccination status was known for 28% of cases, with 87.3% being unvaccinated.
  • Among serotype b cases, 75% had known vaccination status, with the majority (50%) unvaccinated.
  • The third dose of Hib vaccine had a median coverage of 94% across the EU/EEA in 2023, similar to previous years.

• Public Health Implications:

  • The post-pandemic rebound in Hib cases underscores the importance of maintaining high vaccination coverage.
  • Continued surveillance of serotype distribution and vaccine effectiveness is crucial.
  • There is a growing need for vaccines targeting broader strains, especially non-capsulated and non-type b strains, to address the evolving epidemiology of Hib.

Key Information

• Increase in Cases:

  • The number of cases in 2023 was the highest since surveillance began in 1996.
  • The rise is attributed to the return to typical respiratory disease transmission patterns following the pandemic.

• Vaccination Impact:

  • Hib vaccination has nearly eradicated Hib-related meningitis in young children.
  • Despite high coverage, breakthrough infections are still observed in partially and fully vaccinated children, highlighting the need for ongoing evaluation of vaccine effectiveness.

• Serotype Replacement:

  • Non-capsulated strains are now dominant, possibly due to vaccine-induced strain replacement, improved detection methods, and demographic changes.
  • Serotype f remains the most common capsulated strain, while serotype e is associated with higher CFR.

• Data Limitations:

  • Clinical presentation, serotype, and vaccination status were not fully reported, with approximately 50% of cases lacking clinical information and 72% lacking vaccination status.
  • These gaps limit the full understanding of the disease's epidemiology and the effectiveness of current prevention strategies.

Conclusion

The 2023 report indicates a significant resurgence of invasive Haemophilus influenzae disease, particularly non-capsulated and non-type b strains. While Hib vaccination has been effective in reducing serotype b cases, the evolving serotype distribution necessitates ongoing surveillance and the development of broader-spectrum vaccines. Maintaining high vaccination coverage, especially among infants and older adults, remains critical to preventing disease resurgence and reducing mortality.