In most settings, children and adults are at equal risk of developing multidrug resistant (MDR) or rifampicin resistant (RR) tuberculosis (TB), but there are important gaps in data that limit this understanding, according to a study that was recently published in the European Respiratory Journal.
World Health Organization (WHO) estimated 484,000 cases of 10 million incident TB cases were MDR (resistance to both rifampicin and isoniazid) or RR in 2018. MDR/RR-TB have significantly higher rates of treatment failure and mortality compared to TB that are not MDR or RR. As a result, treatment of MDR/RR-TB involves expensive, toxic drugs over extended periods of time. Previous evidence suggests that children are not more or less likely to develop or have MDR/RR-TB when compared to adults. New available data in high MDR/RR-TB countries warrants a further country-specific look.
WHO reports annually on aggregated drug resistance surveillance data collected at national or subnational levels; data is collected through surveillance of drug resistance by routinely conducting drug susceptibility testing or periodic drug resistance surveys of a nationally representative sample of patients that is repeated every 5 years if the coverage of drug susceptibility testing is not sufficient. Population-representative surveys and surveillance collected between 2000
to 2018 were used to compare the OR of MDR/RR-TB among children (<15 years) and adults (≥15 years) with TB. Likelihood ratio test was used to assess for an interaction between age group and year at various levels of confidence. ORs less than 1 meant MDR/RR-TB was positively associated with age of at least 15 years; ORs greater than 1 meant MDR/RR-TB was positively associated with age less than 15 years.
Results suggest that in most settings, the odds of drug resistance are the same for children and adults with TB. Of the 212 countries/territories that reported TB data to WHO, 55 countries had good quality, age-disaggregated data for MDR/RR-TB. Of these 55 countries, 16 countries recorded pediatric MDR/RR-TB cases in both 2000-2011 and 2012-2018; 39 had data reported for one period and not the other, and 19 countries relied on periodic surveys.
Of the 55 included countries, there was strong evidence of ORs less than 1 in Germany, Kazakhstan, Lithuania, Peru, Tajikistan, and Uzbekistan and strong evidence of ORs greater than 1 in United Kingdom and Poland. Weak evidence of ORs greater than 1 were found in Finland and Luxembourg. Data from the 16 countries that recorded data in both time periods suggest strong evidence for decreases in the OR in children when compared to adults in Germany (1.64 [95% CI, 1.12-2.39] in 2000-2011 to 0.26 [95% CI, 0.07-1.07]), Kazakhstan (1.03 [95% CI, 0.71-1.5] to 0.38 [95% CI, 0.31-0.45]), and United States (2.34 [95% CI, 1.45-3.80] to 0.63 [95% CI, 0.28-1.42]), but weak evidence for decrease in Belarus, Namibia, and Uzbekistan.
Lack of statistical significance may not be an indication of a similar force of infection in children and adults, but may reflect limitations and lack of available data. The TB diagnostic algorithm changed over time, resulting in variations in case detection.
Overall, the study authors concluded that “[t]here are important gaps in detection, recording and reporting of drug resistance among pediatric TB cases, limiting our understanding of transmission risks and measures needed to combat the global TB epidemic.”
McQuaid CF, Cohen T, Dean AS, et al. Ongoing challenges to understanding multidrug and rifampicin-resistant tuberculosis in children vs adults, Published online September 17, 2020. Eur Respir J. doi:10.1183/13993003.02504-2020