Haemophilus influenzae type b (Hib)
Haemophilus influenza are bacteria commonly found in the upper respiratory tract, which are transmitted by droplets from people who are infected (but not necessarily symptomatic) to those who are susceptible. The time between infection with Hib and the appearance of symptoms is 2 to 10 days. If these bacteria enter the blood stream, becoming ‘invasive’, they can cause pneumonia, meningitis, sepsis, or other serious diseases. If the bacteria spread to the sinuses or the middle ear, this can lead to sinusitis or otitis media, a painful type of ear infection.
Although Hib diseases may occur in any age group, over 90% of cases of invasive Hib disease occur in children <5 years of age. Hib meningitis can lead to complications such as blindness, deafness, and learning disabilities and sometimes can lead to death.
Antibiotic resistance is a growing challenge, with antibiotic-resistant strains now found in all regions of the world.
Hib conjugate vaccines have been in use since the early 1990s and have led to dramatic declines in invasive Hib disease in 192 countries. In the European Region, 51 of 53 Member States have implemented WHO’s recommendation of including conjugate Hib vaccines in the infant immunization programme.
Vaccination remains the only effective means of preventing Hib disease and is becoming increasingly important as Hib antibiotic resistance grows.
- Hib vaccine is available in a variety of formulations:
- liquid Hib conjugate vaccine (monovalent);
- liquid Hib conjugate combined with diphtheria-tetanus-pertussis (DTP) and/or hepatitis B;
- Hib conjugate in combination with meningococcal antigens;
- lyophilized Hib conjugate with saline diluent (monovalent) and lyophilized Hib conjugate for use with liquid DTP, or DTP in combination with other antigens – such as inactivated polio vaccine or hepatitis B vaccine.
Hib vaccine, whether given as a monovalent vaccine or in combination with other antigens, is safe. Tenderness or pain have been reported in 20-25% of recipients within 24 hours. These symptoms are usually mild and go away on their own within a few days. Fever or serious adverse reactions after administration of Hib are not common.