Hib disease and vaccine quick facts

Updated April 11, 2025

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Haemophilus Influenzae Type B (Hib)

Haemophilus influenzae type b (Hib) is a bacterial infection that can cause severe illnesses in children, including meningitis, epiglottitis, pneumonia, arthritis, and cellulitis;
Hib meningitis, an infection of the membranes covering the brain and one of the most serious complications of Hib, may occur following an upper respiratory illness. Infection can spread from the sinuses and lungs into the bloodstream and to the brain causing meningitis;
Hib is spread through person-to-person transmission, mostly through the air. It is often found in the respiratory tracts of adults with no noted symptoms or adverse effects. Hib must enter into the bloodstream for it to cause meningitis or other forms of invasive disease;
Hib infection more frequently occurs in infants and children under the age of five. Other high-risk populations can include Alaska Natives, American Indians, adults 65 years of age and older, and persons with certain medical conditions, including immunosuppression;
In general, the transmission of Hib is considered to be limited and when it occurs, it usually affects only close contacts such as household members. Prior to the introduction of the Hib vaccine, most children acquired natural immunity to Hib by the time they were five or six years old.

Hib Vaccine

There are five different Haemophilus influenzae type b (Hib) vaccines available for use in the United States: ActHIB, Hiberix, PedvaxHIB, Pentacel (Hib vaccine combined with diphtheria and tetanus toxoids, acellular pertussis adsorbed, and inactivated poliovirus), and VAXELIS (Hib vaccine in combination with diphtheria and tetanus toxoids, acellular pertussis adsorbed, hepatitis B, and inactivated poliovirus. The CDC recommends infants receive Hib vaccine at 2, 4, and 6 months of age with an additional booster dose between 12 and 15 months of age. Hib vaccine is also recommended by the CDC for use in older children, adolescents and adults with certain medical conditions, however, no Hib vaccines are FDA approved for use in persons over five years of age.
Mild side effects such as redness, warmth, or swelling where the shot was given have been reported in connection with administration of Hib vaccines. Systemic reactions, such as fever and irritability can also occur. Severe reactions involving Hib vaccination were reported during pre-licensing clinical trials and continue to be reported to the Vaccine Adverse Events Reporting System (VAERS). These include deaths, anaphylactic reactions, asthma, pneumonia, convulsions, noninfectious encephalitis, acute pancreatitis, peripheral neuropathy, Guillain-Barre syndrome, sepsis, seizures, and cerebral edema.
All infants and children who participated in Hib vaccine pre-licensing clinical trials also received other vaccines in addition to the Hib vaccine. As a result, it is not possible to determine the specific adverse reaction to monitor for following Hib vaccination. The administration of multiple vaccines also makes it difficult to determine the specific vaccine that might have triggered the reactions reported in both clinical studies and to VAERS.

Using the MedAlerts search engine, as of March 28, 2025, there have been 96,969 reports of Hib vaccine reactions, hospitalizations, injuries and deaths following Hib vaccinations made to the federal Vaccine Adverse Events Reporting System (VAERS), including 2,978 related deaths, 19,870 hospitalizations, and 1,864 related disabilities. Nearly 84 percent of HIB vaccine-related adverse events occurred in children under three years old. Of the Hib-vaccine related deaths reported to VAERS, nearly 92 percent of the deaths occurred in children under three years of age. Of these reported deaths, 2,208 occurred in infants under the age of 6 months.
As of April 1, 2025 , there had been 181 claims filed in the federal Vaccine Injury Compensation Program (VICP) for injuries and deaths following HIB vaccination, including 34 deaths and 147 serious injuries.

Food & Drug Administration (FDA)

ActHib (Sanofi Pasteur) - Haemophilus b Conjugate Vaccine (Tetanus Toxoid Conjugate) Product Insert and Licensing Information
HIBERIX (GlaxoSmithKline Biologicals) Haemophilus b Conjugate Vaccine (Tetanus Toxoid Conjugate) Product Insert and Licensing Information
PedvaxHib (Merck Sharp & Dohme Corp.) - Haemophilus b Conjugate Vaccine (Meningococcal Protein Conjugate) Product Insert and Licensing Information
Pentacel (Sanofi Pasteur) - Diphtheria and Tetanus Toxoids and Acellular Pertussis Adsorbed, Inactivated Poliovirus and Haemophilus b Conjugate (Tetanus Toxoid Conjugate) Vaccine Product Insert and Licensing Information
VAXELIS (MCM Vaccine Company) Diphtheria and Tetanus Toxoids and Acellular Pertussis Adsorbed, Inactivated Poliovirus, Haemophilus b Conjugate Meningococcal Protein Conjugate and Hepatitis B Recombinant Vaccine Product Insert and Licensing Information

Centers for Disease Control (CDC)

Vaccine Reaction Symptoms & Ingredients

Our Ask 8, If You Vaccinate webpage contains vaccine reaction symptoms and more.

Search for Vaccine Reactions

NVIC hosts MedAlerts, a powerful VAERS database search engine. MedAlerts examines symptoms, reactions, vaccines, dates, places, and more.

Reporting a Vaccine Reaction

Since 1982 the NVIC has operated a Vaccine Reaction Registry, which has served as a watchdog on VAERS. Reporting vaccine reactions to VAERS is the law. If your doctor will not report a reaction, you have the right to report a suspected vaccine reaction to VAERS.

IMPORTANT NOTE: NVIC encourages you to become fully informed about Haemophilus Influenzae Type B (Hib) and the Hib vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.