Primary Tuberculosis Infection in 35 Children at a Swedish Day Care Center

Abstract

The manifestations of primary TB in children today are similar to those described 50-70 years ago. The tuberculin skin test is an effective tool for contact tracing in an unvaccinated, previously nonexposed childhood population. Rapid detection of contagious patients and thorough contact investigation remain our most important means to reduce transmission.

Epidemiology and disease burden of tuberculosis in children: a global perspective

“…Whether uninfected older children are more likely than uninfected younger children to develop a positive infection test following known exposure is unclear. Outbreak investigations in low prevalence settings suggest that perhaps younger children are more vulnerable, but this may be explained by increased intensity of exposure 54. Although BCG has well- established efficacy against the progression from TB infection to severe forms of disease, there is emerging evidence that it may also protect against the establishment of infection 55–58.…”

Infectious Diseases of Poverty in Children

“…Poverty increases a child's risk of TB exposure through cultural practices around child care [31], overcrowding in school and at home [32–36], poor housing with inadequate ventilation [37, 38], adults in household with comorbidities such as HIV [39], seasonal and environment-related exposure [40–42], and lack of public health infrastructure [43]. Following TB exposure, risk of a child developing infection is influenced by the acid fast bacilli (AFB) sputum positivity of the source case [33], duration and intensity of exposure [35, 44], infectiousness of the TB strain [45, 46], co-infections [47, 48], and the child's immune and genetic makeup [49, 50]. …”

Risk of developing tuberculosis after brief exposure in Norwegian children: results of a contact investigation

“…7 On the contrary, extensive transmission to both adults and children of particular strains of Mycobacterial tuberculosis has been reported, even after a few hours exposure. 8 In February 2010, a 20-year-old native-born Norwegian man was diagnosed with smear-positive pulmonary tuberculosis.…”

“…Non-native born abroad more than 8 h. 13 14 A Swedish study reported that no tuberculosis transmission took place among 53 visiting children who were exposed to a highly infectious helper less than 3 days in a day-care centre, corresponding to a total exposure time of less than 24 h. 7 Thus, our study and the Swedish study quite similarly found that less than 18-24 h exposure may not pose a significant risk for healthy children attending day-care or after-school-care centres in Norway and Sweden. However, tuberculosis transmission is complex and several factors other than exposure time influence the risk of being infected, in particular infectivity of the index case, various characteristics of the exposed children such as low age and vulnerability, and how close the exposure has been in terms of physical contact, room size and air quality.…”

“…5 6 An outbreak in a Swedish day-care centre documented that more than half of the attending children were infected after 5 months daily exposure to a preschool teacher with cavitary pulmonary tuberculosis. 7 None of 53 children who had visited the centre less than 3 days were ARTICLE SUMMARY Article focus ▪ It is well known that prolonged exposure to adults with smear-positive pulmonary tuberculosis increases the risk of being infected in children. ▪ Limited evidence exists on the risk of brief exposure among children in day-care or after-school-care facilities in high-income countries.…”