Every week during the winter season, TB Control/Refugee Health Program staff and University of Utah medical students have placed TSTs on Monday and Tuesday nights, and read the results on Wednesday and Thursday nights. All clients who have a positive TST have been referred to the Fourth Street Clinic for further evaluation. Although the importance of follow up at the Fourth Street Clinic has been explained to the clients, only 11 clients out of the 28 who had positive TSTs have gone to the Fourth Street Clinic for further evaluation. None of the eleven have been found to have active TB disease. Two major problems facing the Emergency Winter Shelter Testing Program are getting clients to return 48-72 hours after having a TST placed to get their TST result read, and getting clients with positive TSTs to go to the Fourth Street Clinic for further evaluation. Incentives, or small rewards (i.e., food coupons, sweatshirts, socks, underwear), are given to those clients who do return for a test reading or clinic follow-up in an attempt to address these problems. It is anticipated, however, that getting clients to return for appropriate follow-up will be an ongoing problem. Most homeless people live under extreme circumstances and may have other problems (i.e., substance abuse) that make it difficult for them to comply with follow-up instructions.

With the recent introduction of the Pneumococcal 7-valent pediatric vaccine (Prevnar^TM) it seemed like a good time for a review of pneumococcal disease.

The bacterium Streptococcus pneumoniae (pneumococcus) is the most common cause of invasive bacterial infections in children. Since the Haemophilus influenzae type B conjugate vaccine has been available, pneumococci and meningococci have become the two most common causes of bacterial meningitis in infants and young children. Pneumococci are also a frequent cause of otitis media, sinusitis, and community-acquired pneumonia. As with many other microorganisms, pneumococci find their ecologic niche in colonizing the nasopharynx and may be isolated from the nasopharynx of five to 70% of healthy adults¹. The rate of asymptomatic carriage varies with age and environment. The spread of the organism within a family or household is influenced by factors such as crowding, season, and the presence of upper respiratory infections. Transmission occurs as the result of direct person-to-person contact via respiratory droplets. The spread of invasive pneumococcal disease is usually associated with increased carriage rates. Resistance to antibiotics commonly used to treat pneumococcal disease is increasing. In some areas of the U.S. up to 35% of invasive pneumococcal isolates are not susceptible to penicillin².

Utah has averaged 17 cases of invasive pneumococcal disease annually over the last five years with the majority of cases occurring in children >2 years of age (Figure 1). Pneumococci cause an estimated 50,000 cases of invasive disease in the U.S. annually. Children with functional or anatomic asplenia, particularly those with sickle cell disease, and children with HIV infection are at very high risk of invasive disease, with rates in some studies more than 50 times higher than children of the same age without these conditions. Children of certain racial and ethnic groups also have increased rates, particularly children of Alaskan Native, certain American Indian groups, and of African American origin¹. The reason for this increased risk by race and ethnicity is not known.

Pneumococcal Vaccines

The 23-valent pneumococcal polysaccharide vaccine has been available for the prevention of pneumococcal disease since 1983. It is 60% to 70% effective in preventing invasive pneumococcal disease and is recommended for all persons >65 years of age, as well as persons >2 years of age with chronic cardiovascular, pulmonary, metabolic, or hepatic illnesses, or those with immune compromise. This vaccine is not effective in children <2 years of age or in reducing nasopharyngeal carriage of pneumococci³.

The first pneumococcal conjugate vaccine (PCV7) Prevnar^TM was licensed in the United States in 2000. It includes purified capsular polysaccharide of the seven serotypes most commonly isolated from children with invasive disease. It was shown to reduce invasive disease caused by vaccine serotypes by 97%. Prevnar^TM contains no thimerosal or other preservatives. This vaccine is recommended for all children <2 years of age as well as children 24-59 months of age who are at high risk for invasive pneumococcal disease (e.g., children with sickle cell disease, human immunodeficiency virus infection, and other immunocompromising or chronic medical conditions). This vaccine should be considered for children 24-59 months of age who are of African-American, Alaska Native, or American Indian descent; and those who attend group child care¹. It is currently unknown if this vaccine is effective in reducing nasopharyngeal carriage.

References:

1. CDC. Preventing pneumococcal disease among infants and young children: Recommendations of the ACIP. MMWR 2000;49:1-35.

2. CDC. Active Bacterial Core Surveillance. Available at HYPERLINK http://www.cdc.gov/ncidod/dbmd/abcs. (Accessed March 2,2001).