1. What is Hib infection?

Hib (Haemophilus influenzae type b) is a bacterium that can cause severe, invasive infections – including meningitis, sepsis, epiglottitis, or pneumonia.

How does infection occur? Most often by airborne droplets (coughing, sneezing, close contact) and by contact with secretions from the nose/throat of an infected person.

Who is the source of the pathogen? The source can be a sick person or an asymptomatic carrier – Hib can exist in the nasopharynx and spread further despite no typical symptoms.

Incubation period: Usually assumed to be approx. 2–4 days (can be longer).

Who is most at risk? The greatest risk of severe course concerns children up to 5 years of age, especially between 6 and 24 months of age, and children staying in clusters (nurseries/kindergartens).

2. Symptoms of Hib infection

Hib can "descend" from the nasopharynx to other organs and cause different forms of the disease. The most common and dangerous are:

meningitis (e.g., severe headache, vomiting, disturbances of consciousness, stiff neck),
sepsis / blood infection (e.g., high fever or chills, very poor general condition, drowsiness, "lack of contact"),
pneumonia (fever, cough, shortness of breath, chest pain),
epiglottitis (rarer, but very dangerous – can quickly impede breathing).

Possible complications: After severe infection (especially after meningitis), neurological complications may persist, including hearing loss/deafness, epilepsy, gait disorders, reduced intellectual performance.

When is urgent medical consultation necessary? Immediately seek help if a child (or adult) develops:

symptoms of possible meningitis (severe headache, stiff neck, drowsiness, confusion, vomiting),
symptoms of sepsis (sudden deterioration of condition, "lack of contact", breathing difficulties),
increasing shortness of breath, drooling, difficulty swallowing (suspicion of epiglottitis).

3. Where does Hib occur?

Hib occurs all over the world. The risk of severe cases is greatest where vaccinations are less common – that is why population vaccinations have very clearly limited the number of cases in countries that introduced them.

For whom is this information most important? Primarily for parents of small children (nursery/kindergarten, frequent infections in the environment), as well as for people with selected immunity problems (more below).

4. How to protect yourself against Hib?

A. General prevention

Hand hygiene and learning cough/sneeze hygiene.
Avoiding close contact with people with acute respiratory tract infection (as far as realistic in small children).
In case of suspected severe infection – quick medical consultation (Hib can develop rapidly).

B. Vaccination (most important)

Type of vaccine: The Hib vaccine is conjugated (not "live") and cannot cause Hib infection.

For whom recommended?

routinely for infants and young children (mandatory vaccination in Poland),
and for selected people from risk groups – in Poland, among others, in patients with anatomical or functional asplenia, vaccination is treated as mandatory and free (rules are set by a doctor).

Vaccination schedule in Poland (mandatory vaccinations):

4-dose schedule:
- primary doses: 7–8 weeks of age, 3–4 months, 5–6 months,
- booster dose: 16–18 months of age.

Booster / supplementary doses: The booster dose is an element of the calendar (16–18 months of age). Additional schedules (e.g., in case of delays or in risk groups) are determined by the doctor.

Effectiveness and impact on bacterial spread: Hib vaccines are very effective (PZH materials indicate effectiveness reaching approx. 95%) and also limit colonization/carriage, which reduces transmission.

Duration of immunity: After a correctly implemented schedule with a booster dose, protection is long-lasting in the key period of greatest risk (infants and young children). That is why the calendar includes a booster dose in the 2nd year of life.

5. Summary

Hib is a bacterium that can cause very severe infections in small children (e.g., sepsis, meningitis, epiglottitis). The surest protection is vaccination – in Poland, it is mandatory and implemented from the 2nd month of life in a schedule with a booster dose at 16–18 months. It is particularly worth ensuring the dates in children up to 5 years old (highest risk) and in people from selected risk groups (e.g., asplenia). If you are planning nursery/kindergarten or a trip and the child has delays in vaccinations – it is best to discuss the plan for catching up on doses with a doctor as early as possible.