Description

Streptococcus pneumoniae, also known as pneumococcus, is a bacterium that is often found in the noses and throats of healthy persons and is spread person-to-person through close contact. Pneumococcus is a common cause of mild illnesses, such as sinus and ear infections, but also causes life-threatening infections such as pneumonia, meningitis, and infections of the bloodstream. Many strains are resistant to antibiotics (1,2).

Occurrence

Pneumococcal disease occurs worldwide. Pneumococcal disease is more common in winter months and when respiratory viruses such as influenza are circulating. Outbreaks of pneumococcal disease are not common but can occur in child care centers, nursing homes, or other institutions. In the United States, most deaths from pneumococcal disease occur in older adults, although in developing countries many children die of pneumococcal pneumonia. In 2000, a new pneumococcal conjugate vaccine (PCV) (Prevnar, Wyeth Vaccines) was introduced in the United States for routine childhood use and has reduced dramatically the incidence of severe pneumococcal disease in children. Because the vaccine also interrupts person-to-person transmission of pneumococci, the incidence of severe pneumococcal disease in older children and adults has also declined (3,4). As of 2006, other countries routinely using the new vaccine include Canada, Australia, Qatar, the United Kingdom, and an increasing number of other countries in Western Europe.

Risk for Travelers

Risk for pneumococcal disease is highest in young children, the elderly, and persons of any age who have chronic medical conditions such as heart disease, lung disease, or diabetes, or conditions that suppress the immune system, such as HIV (5,6). Smokers and those in close contact with small children are also at higher risk. Crowded settings or situations with close, prolonged contact with young children may increase the risk of contracting pneumococcal disease while traveling.

Clinical Presentation

Fever and malaise are typical symptoms for all forms of pneumococcal disease and may be the only symptoms in young children with blood infections. Patients with pneumonia usually have cough, often with purulent or blood-tinged sputum, and may have shaking chills, shortness of breath, or pleuritic chest pain. Fever and sputum production may be absent in elderly persons with pneumococcal pneumonia. Pneumococcal meningitis, ear infections or sinus infections resemble these conditions caused by other bacteria.

Prevention

VACCINES

Two vaccines are available to prevent pneumococcal disease; the pneumococcal conjugate vaccine (PCV7) (Prevnar, Wyeth Vaccines) and the pneumococcal polysaccharide vaccine (PPV23) (Pneumovax, Merck). Both vaccines provide protection by inducing antibodies to specific types of pneumococcal capsule and are effective at preventing invasive disease,. The conjugate vaccine (PCV7), licensed for use in young children, also prevents some pneumonia and ear infections.

Pneumococcal conjugate vaccine

The pneumococcal conjugate vaccine is part of the routine infant immunization schedule in the U.S. and is recommended for all children <2 years of age and children 2-4 years of age who have certain underlying conditions (see Chapter 8) (7).

Pneumococcal polysaccharide vaccine

The pneumococcal polysaccharide vaccine is part of the routine adult immunization schedule but many adults who should have received the vaccine have not (8,9). In 2003, only 64% of adults ≥65 years of age had received the vaccine (10).

A single dose of pneumococcal polysaccharide vaccine should be given at age 65 years or to persons 2-64 years of age at the time a high-risk condition is recognized. Children 2-4 years of age with indications for pneumococcal polysaccharide vaccine should receive polysaccharide vaccine at least 2 months after receiving doses of conjugate vaccine. Persons with an indication for polysaccharide vaccine but with unknown vaccination history should receive one dose. A second dose of vaccine should be used for the following groups:

• persons 65 years of age and older who received the vaccine at least 5 years before and were less than 65 years of age at the time of initial vaccination;
• persons with sickle cell disease, asplenia, renal disease, hematologic or generalized malignancy, or other immunocompromising condition.

For children younger than 10 years of age, the second dose may be given 3 years or more after the first dose; for older persons, revaccination may be given after 5 years. Because of limited data on the safety of multiple doses and on the duration of protection provided by polysaccharide vaccine, recommendations are for a single revaccination 3-5 years after the initial dose. These recommendations have been misinterpreted as suggesting revaccination every 5 years.

Safety/Side Effects

Mild local reactions such as redness, swelling, or tenderness occur in 10%-23% of infants after receipt of PCV7. Larger areas of redness or swelling or limitations in arm movement may occur in 1%-9%. For PPV23, mild, local side effects occur in approximately half of vaccine recipients and are more common after revaccination. Local reactions usually resolve by 48 hours after vaccination. More severe local reactions are rare. After PCV7, low-grade fever can occur in up to 24% of children and fever higher than 102.2°F may occur in up to 2.5% of vaccinees. Systemic symptoms, including myalgias and fever, are rare after PPV23.

Precautions and contraindications

PCV7 is contraindicated for children known to have a hypersensitivity to any component of the vaccine. Health-care providers may delay vaccination of children with moderate or severe illness until the child has recovered, although minor illnesses, such as mild upper-respiratory tract infection with or without low-grade fever, are not contraindications. Revaccination with PPV23 is contraindicated for persons who had a severe reaction (e.g., anaphylactic reaction or localized arthus-type reaction) to the initial dose (see also Chapter 1 for general recommendations and Chapter 8 and 9 for special populations).

ADDITIONAL PREVENTIVE MEASURES

Persons who smoke cigarettes can reduce their risk of pneumococcal disease by stopping smoking. In addition, improving control of chronic conditions that are predisposing factors for pneumococcal disease, such as diabetes and HIV, may reduce risk. Chemoprophylaxis is not routinely recommended for travelers unless otherwise recommended by the health-care practitioner supervising their care.

Treatment

Pneumococcal disease of all types is usually treated with antibiotics. Mild forms such as uncomplicated ear or sinus infections in healthy persons may resolve without treatment (11). Because pneumococcal disease is endemic worldwide, care from a physician specializing in travel or tropical medicine is not required.

References

1. Pneumococcal Infections. In: Pickering L, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. Elk Grove Village, IL: American Academy of Pediatrics; 2006. p. 525-37.
2. Robinson KA, Baughman W, Rothrock G, Barrett NL, Pass M, Lexau C, et al. Epidemiology of invasive Streptococcus pneumoniae infections in the United States, 1995-1998: Opportunities for prevention in the conjugate vaccine era. JAMA. 2001;285(13):1729-35.
3. Whitney CG, Farley MM, Hadler J, Harrison LH, Bennett NM, Lynfield R, et al. Decline in invasive pneumococcal disease after the introduction of protein-polysaccharide conjugate vaccine. N Engl J Med. 2003;348(18):1737-46.
4. CDC. Direct and indirect effects of routine vaccination of children with 7-valent pneumococcal conjugate vaccine on incidence of invasive pneumococcal disease—United States, 1998-2003. MMWR Morb Mortal Wkly Rep. 2005;54(36):893-7.
5. Fedson DS, Scott JAG. The burden of pneumococcal disease among adults in developed and developing countries: what is and is not known. Vaccine. 1999;17(Supplement 1):S11-S18.
6. Greenwood B. The epidemiology of pneumococcal infection in children in the developing world. Phil Trans R Soc Lond B Biol Sci. 1999;354:777-85.
7. CDC. Preventing pneumococcal disease among infants and young children: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2000;49 (No. RR-9):1-35.
8. CDC. Prevention of pneumococcal disease. MMWR Morbid Mortal Wkly Rep. 1997;46(RR-8):1-20.
9. Whitney CG, Schaffner W, Butler J. Rethinking recommendations for use of pneumococcal vaccines in adults. Clin Infect Dis. 2001;33:662-75.
10. CDC. Influenza and pneumococcal vaccination coverage among persons aged ≥65 years and persons aged 18-64 years with diabetes or asthma—United States, 2003. MMWR Morb Mortal Wkly Rep. 2004;53:1007-12.
11. Tunkel AR, Hartman BJ, Kaplan SL, Kaufman BA, Roos KL, Scheld WM, et al. Practice guidelines for the management of bacterial meningitis. Clin Infect Dis. 2004;39:1267-84.

MATTHEW MOORE, CYNTHIA WHITNEY