Research and analysis

Laboratory reports of Haemophilus influenzae by age group and serotype, England: annual 2025 (and 2024)

Updated 30 July 2026

Applies to England

During 2025 (January to December inclusive), there were 602 laboratory confirmed cases of invasive Haemophilus influenzae (Hi). This was a 14.1% decrease compared to 2024 (602 in 2025 compared with 701 in 2024) (see table).

Restrictions due to the COVID-19 pandemic were associated with reductions in a number of infections including invasive Haemophilus influenzae disease during 2020 (1), with cases remaining low during 2021 and since rebounding in 2022.

In 2025, all invasive Hi isolates were serotyped. Of those serotyped, most isolates were non-encapsulated Hi (ncHi) (83.1%; 500 of 602) – this compares to 84.5% (592 of 701) in 2024.

In 2025, there were 20 cases of invasive H. influenzae type b (Hib) disease, accounting for 3.3% (20 of 602) of all invasive Hi cases, compared to 2.1% (15 of 701) in 2024. Of the 20 Hib cases, 18 were diagnosed in persons over the age of 15 years and 2 were in children under the age of 5 years.

In 2025, there were 26 cases of invasive H. influenzae type a (Hia) disease, accounting for 4.3% (26 of 602) of all invasive Hi cases, compared to 3.1% (22 of 701) in 2024. Of the 26 Hia cases, 15 were diagnosed in persons over the age of 15 years, 1 case aged between 5-14 years and 10 were in children under the age of 5 years.

There were 56 (9.3%) cases of invasive disease due to other Haemophilus influenzae types in 2025 including: one serotype d, 11 (1.8%) serotype e and 44 (7.3%) serotype f. In 2024, one case was due to serotype c, 14 (2.0%) were due to serotype e and 57 (8.1%) were due to serotype f.

The incidence rate of invasive Haemophilus influenzae disease across all ages remains low at 1.03 per 100,000 population during 2025, of which most cases (85.9%; 517 of 602) were aged 15 years and over. Infants aged less than 1 year accounted for 6.3% (38 of 602) of cases in 2025 (see table). The incidence rate for Hib and Hia cases across all ages show gradual increases, reaching 0.034 and 0.044 per 100,000 population during 2025, respectively.

Hib incidence rates appear to be returning to levels seen in 2013, with the majority of cases occurring in individuals over 5 years of age. In contrast, Hia incidence rates and counts have demonstrated a consistent upward trend since 2018.

The most recent child death attributed to invasive Hib disease was in 2011.

In conclusion, invasive Hib disease continues to be well controlled across all age groups in 2025. The number of cases of invasive Hia disease, however, has increased in recent years most notably among those aged under 1 year and above 15 years.

Number of Haemophilus influenzae cases by serotype and age group, England, 2023 and 2024

(‘Not typed’ refers to samples that have not been received at the reference laboratory for typing, have failed to re-culture, or results were equivocal.)

Type	Under 1 year 2024	Under 1 year 2025	1 to 4 years 2024	1 to 4 years 2025	5 to 14 years 2024	5 to 14 years 2025	15+ years 2024	15+ years 2025	Total 2024	Total 2025
a	5	8	3	2	0	1	14	15	22	26
b	0	2	2	0	1	0	12	18	15	20
c	1	0	0	0	0	0	0	0	1	0
d	0	0	0	0	0	0	0	1	0	1
e	0	0	1	0	1	0	12	11	14	11
f	1	1	5	2	0	1	51	40	57	44
Non capsulated	27	27	27	24	17	17	521	432	592	500
Total	34	38	38	28	19	19	610	517	701	602

Total cases of Haemophilus influenzae type b by year, 2006 to 2025

Reference

1. Brueggemann AB, Jansen van Rensburg MJ, Shaw D, McCarthy ND, Jolley KA, Maiden MCJ and others (2021). ‘Changes in the incidence of invasive disease due to Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis during the COVID-19 pandemic in 26 countries and territories in the Invasive Respiratory Infection Surveillance Initiative: a prospective analysis of surveillance data’ The Lancet Digital Health: volume 3, issue 6