Haemophilus influenzae: guidance, data and analysis

Haemophilus influenzae is a Gram-negative coccobacillus that can cause serious invasive disease in children and adults. The most prevalent strain is type b (Hib).

The organism is differentiated into 6 capsulated serotypes (Hia to Hif) and non-encapsulated (ncHi) strains.

Prior to routine immunisation, H. influenzae serotype b (Hib) accounted for more than 80% of invasive H. influenzae disease. Hib was a leading cause of bacterial meningitis, mainly in children aged under 5 years.

Making the Hib conjugate vaccine part of the national childhood immunisation programme in 1992 dramatically reduced the incidence of invasive Hib disease across all age groups.

See NHS choices for more information about Hib.

Diagnosis and management

Data collection

Following the decline in invasive Hib disease, Public Health England (now UK Health Security Agency) extended its enhanced surveillance to include all cases of invasive Haemophilus influenzae infections across all age groups in England and Wales (January 2009 onward).

Clinicians, microbiologists and public health doctors can report all cases of invasive H. influenzae infections to UK Health Security Agency (UKHSA) respiratory and vaccine preventable bacteria reference unit (RVPBRU) and refer the isolate for confirmation and serotyping if this has not already been done.

UKHSA also identifies cases reported through the NHS hospital microbiology electronic laboratory reporting system, LabBase2.

A case of H. influenzae infection is considered invasive if the organism was isolated from a normally sterile site, such as blood culture, cerebrospinal fluid (CSF), joint fluid, pleural fluid, or similar.

For all cases, RVPBRU sends an age and gender appropriate questionnaire requesting information on clinical presentation, risk factors, complications and outcome to the patient’s general practitioner (GP), though any clinician can complete the questionnaire.


Figures for laboratory confirmed Hib cases from 2013 and earlier are available from the Health Protection Report archive. Select ‘Immunisation’ and navigate by calendar year.


The cover of vaccination evaluated rapidly (COVER) programme records how many children are vaccinated in the UK against diseases including Hib.

Published 1 April 2013
Last updated 26 January 2022 + show all updates
  1. Added Haemophilus influenzae: laboratory reports by age group and serotype.

  2. Added reports for 2015, 2017, 2018 and 2019.

  3. First published.