Effective June 30, 2018, if you have not upgraded to a current browser you will no longer be able to view or make transactions on MerckVaccines.com. To protect your credit card information, Merck follows security requirements mandated by the PCI Security Standards Council. The PCI Security Standards Council has mandated that all companies that transact payments with credit cards must restrict the use of insecure browsers.
You can learn more about the specific PCI requirement here.
Common Types of Invasive Diseases Caused by Hib Prior to 1990.1
Symptoms and Complications of Diseases Caused by Hib
Meningitis occurs when the bacterium invades the meninges (three protective layers of the brain membrane that contain fluids and tissue) and causes inflammation and swelling. Classic symptoms include: fever, bulging fontanelle (soft spot on top of baby’s head), stiff neck, and decreased mental state. In young infants, symptoms may also include altered alertness, poor feeding, and irritability. Long-term complications from meningitis could include: mental retardation, cerebral palsy, hearing loss, and seizure disorders.1,2
Epiglottitis occurs when the bacterium invades the epiglottis (flap in the throat that covers the windpipe) and surrounding tissue and causes inflammation and swelling. Symptoms include: fever, severe sore throat, abnormal and high-pitched sound when breathing, difficult and painful swallowing, drooling, anxious and restless behavior, and discomfort when sitting up or leaning forward. Swelling may lead to airway obstruction and death within hours if left untreated.2,3
Pneumonia caused by Hib is common in children (4 months to 4 years old) and is difficult to differentiate from other bacterial pneumonias. It typically presents in winter and spring, and severe cases may require hospitalization.3
Arthritis refers to septic arthritis, which is when the infection occurs in the fluids in the joints.2 Symptoms include: joint pain, swelling, redness of the skin, limited range of motion, and fever.2
Cellulitis can be characterized as a fast-progressing skin infection involving the neck, head, and face.1
Hib bacteria are thought to spread primarily through contact with respiratory droplets expelled from an infected person. Although the contagious potential of the Hib bacteria is thought to be limited, close contact with case-patients (eg, childcare, household, or institutional setting) can also lead to disease transmission.1
Confirmation of Hib disease may require various blood or fluid samples (eg, spinal fluid and other body cavity fluids) to be cultured on appropriate media. A positive culture for H. influenzae establishes the diagnosis.1,3
The human body can usually fight against Hib infection by developing antibodies called anti-PRP (antibody against the bacterium’s outer layer composed of the polysaccharide, polyribosylribitol phosphate [PRP]).3
Children Up to 6 Years Old Were Most Susceptible to Invasive Hib Disease (prevaccine era)1,3
Risk Period of Symptomatic Invasive Disease
3 years old
4 years old
5 years old
6 years old
Anti-PRP transferred from the mother during pregnancy or breastfeeding begins to decline at birth and reaches the lowest level at 6 months. In the prevaccine era, up to 60% of invasive disease occurred before age 12 months, with a peak occurrence among children 6–11 months of age.1
3 to 5 years old
At this age, children gradually acquire anti-PRP through repeated exposure and therefore are more susceptible to disease.
6 years old
Over time, children naturally acquire anti-PRP, and invasive disease is rare in children aged 6 years and older.
Usually, children over 6 years old and adults have naturally acquired enough anti-PRP that they are no longer susceptible to invasive Hib disease.3
DISCLAIMER: By clicking on the link below, you will be directed away from MerckVaccines.com to another Web site. Merck does not review or control the content of the site to which the hyperlink connects; therefore, the hyperlink does not constitute an endorsement by Merck.
Centers for Disease Control and Prevention (CDC). Haemophilus influenzae type b. In: Hamborsky J, Kroger A, Wolfe S, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases. 13th ed. Washington, DC: Public Health Foundation; 2015:119–134. http://www.cdc.gov/vaccines/pubs/pinkbook/index.html. Accessed August 29, 2018.
Chandran A, Watt JP, Santosham M. Haemophilus influenzae vaccines. In: Plotkin SA, Orenstein WA, Offit PA, eds. Vaccines. 7th ed. Philadelphia, PA: Elsevier Saunders; 2013:167–182.
Murphy TF. Haemophilus influenzae. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:2575–2583.
Grant LR, Hammitt LL, Murdoch DR, et al. Procedures for collection of induced sputum specimens from children. Clin Infect Dis. 2012;54(suppl 2):S140–S145.