HIV). All of the speakers emphasized the particular difficulties of reaching vulnerable populations and the steps that must be taken to identify, diagnose, and treat MDR TB among these groups.
A major risk for pediatric TB is contact with an infected adult, observed Soumya Swaminathan, Head, Division of Clinical Research, National Institute for Research in Tuberculosis. Rates of infection among adults aged 25–44 are highest in the African region, followed by Southeast Asia (Figure 6-1), and the risk of TB in children is likely to be correspondingly high in these regions. Other risk factors include large household size, severe malnutrition, exposure to household smoke, having a female index case, and in some cases, being a member of certain minorities.
Like adults, children tend to go through several phases after infection with M.tb. After an initial phase marked by hypersensitivity responses and skin test conversion, which typically occur in the first 6–8 weeks, the primary disease follows. Most of the disseminated disease tends to occur in the first 2–4 months after infection. Lymph node disease in younger children and pleural disease in older children can occur at 6–8 months. The adult form of the disease, which generally is seen in older children, can occur several years after infection.
Swaminathan explained that more children than adults with TB are smear-negative, although this varies with the population under study. In one study of 1,098 children seen at the LRS Institute of Tuberculosis and Respiratory Diseases in New Delhi, 414 children were smear-positive, 404 were smear-negative, and sputum status was not known for 280 patients (Sharma et al., 2008). The smear-positivity rate was higher among older children—about 60 percent—but even among children younger than 6 years old, 30 percent were smear-positive.
Unknown Burden of Pediatric MDR TB
Data on MDR TB in children are virtually nonexistent. WHO does not include children in drug resistance surveys, and most countries have not collected these data systematically. A plan to gather data on children is urgently needed, said Swaminathan.
1 This section is based on the presentation of Soumya Swaminathan, who was Coordinator for Neglected Priorities Research with the WHO Special Programme for Research and Training in Tropical Diseases (TDR) at the time of the workshop. Since the workshop, Swaminathan has rejoined the National Institute for Research in Tuberculosis as Head, Division of Clinical Research.