Prevalence of latent tuberculosis infection and its risk factors among senior students from four primary schools in Shanghai / 中华传染病杂志

ABSTRACT

Objective To investigate the prevalence of latent tuberculosis infection(LTBI),and to identify the risk factors in primary schoolchildren from Shanghai through the population-based field investigation combined with the tuberculosis infection enzyme-linked immunospot assay(T-SPOT.TB)assay.Methods The children in grade 4 and 5 were enrolled from four primary schools in Pudong new district and Yangpu district of Shanghai.Questionnaire interview was applied to investigate the soeiodemographic and clinical information related to LTBI.The T-SPOT.TB assay was used to detect LTBI in the enrolled subjects.Univaitate and multivariate analyses were used to identify the risk factors associated with LTBI among the primary schoolchildren.Results Totally 472 schoolchildren were enrolled in the present study,with 439(93.0%)being vaccinated with bacillus calmette-guerin (BCG) and ten (2.1%) having contact history with tuberculosis (TB) patients.Among the 472 eligible subjects,16(3.4%) children were T-SPOT.TB positive,who had no clinical symptoms andsigns relevant to TB and were defined as LTBI.The LTBI prevalence in BCG vaccinated and unvaccinated children were 2.7% and 12.1%,respectively (OR6.972;95%CI1.834-26.500);those in TB contacts and children without TB contact history were 30.0% and 2.8%, respectively (OR 16. 38; 95% CI 3. 692-72. 700). Conclusions The prevalence of LTBI among senior schoolchildren in Shanghai is 3.4%. BCG vaccination is protective for children from LTBI, while daily contacts with TB patients increases the risk of LTBI in schoolchildren.