Low secondary attack rate after prolonged exposure to sputum smear positive miliary tuberculosis in a neonatal unit.

BACKGROUND: Several neonatal intensive care units (NICU) have reported exposure to sputum smear positive tuberculosis (TB). NICE guidelines give support regarding investigation and treatment intervention, but not for contact definitions. Data regarding the reliability of any interferon gamma release assay (IGRA) in infants as a screening test for TB infection is scarce. We report an investigation and management strategy and evaluated the viability of IGRA (T-Spot) in infants and its concordance to the tuberculin skin test (TST). METHODS: We performed an outbreak investigation of incident TB infection in a NICU after prolonged exposure to sputum smear positive miliary TB by an infant's mother. We defined individual contact definitions and interventions and assessed secondary attack rates. In addition, we evaluated the technical performance of T-Spot in infants and compared the results with the TST at baseline investigation. RESULTS: Overall, 72 of 90 (80%) exposed infants were investigated at baseline, in 51 (56.7%) of 54 (60%) infants, follow-up TST at the age of 6 months was performed. No infant in our cohort showed a positive TST or T-Spot at baseline. All blood samples from infants except one responded to phytohemagglutinin (PHA), which was used as a positive control of the T-Spot, demonstrating that cells are viable and react upon stimulation. 149 of 160 (93.1%) exposed health care workers (HCW) were investigated. 1 HCW was tested positive, having no other reason than this exposure for latent TB infection. 5 of 92 (5.5%) exposed primary contacts were tested positive, all coming from countries with high TB incidences. In total, 1 of 342 exposed contacts was newly diagnosed with latent TB infection. The secondary attack rate in this study including pediatric and adult contacts was 0.29%. CONCLUSION: This investigation highlighted the low transmission rate of sputum smear positive miliary TB in a particularly highly susceptible population as infants. Our expert definitions and interventions proved to be helpful in terms of the feasibility of a thorough outbreak investigation. Furthermore, we demonstrated concordance of T-Spot and TST. Based on our findings, we assume that T-Spot could be considered a reliable investigation tool to rule out TB infection in infants.

Health-seeking behaviour and treatment delay in patients with pulmonary tuberculosis in Switzerland: some slip through the net.

AIMS OF THE STUDY: To assess the health-seeking behaviour, the patient delay (onset of symptoms to first consultation) and the health system delay (first consultation to start of tuberculosis treatment) among patients with pulmonary tuberculosis (TB) diagnosed in Switzerland, and to assess the predictors of the various types of delay. METHODS: A survey among pulmonary TB patients was carried out in six cantons, covering 42% of all pulmonary adult TB cases notified in Switzerland. Data were collected by collaborators of the cantonal lung associations in charge of the follow-up of TB patients to investigate treatment seeking behaviour and to establish various delays and its predictors. Predictors of percentiles of delay (median and 75th percentile) were assessed using quantile regression. RESULTS: Among 252 eligible patients, 162 patients could be interviewed. Of these, 20.4% were born in Switzerland. Cough as a symptom was mentioned by 76% of the interviewed patients. Almost half of the 162 patients (46%) consulted first a general practitioner in an ambulatory care setting and 26% approached a hospital first. The median delay between symptom onset and first healthcare contact (patient delay) was 5.2 weeks, which is slightly longer than findings in other low prevalence countries. The interquartile range was 1.6 to 14.2 weeks. The median delay between first consultation in Switzerland and the start of TB treatment (health system delay) was 2 weeks. The interquartile range was 0.6 to 7.1 weeks. There were no clear predictors of patient delay. The main predictors of a longer median health system delay were the presence of fever (1.6 weeks, 95% confidence interval [CI] 0.5 to 2.6 weeks), having visited first a general practitioner or a paediatrician (1 week, 95% CI 0.1 to 1.9 weeks) and having seen three or four doctors before beginning TB treatment (2.9 weeks, 95% CI 0.7 to 5.1 weeks). A clear predictor of a shorter median health system delay was having undergone an X-ray at the first consultation (-2.9 weeks, 95% CI -4.8 to -0.9 weeks). Marginally significant for shorter delay was male sex (-2.6 weeks, 95% CI -5.4 to 0.1 weeks). CONCLUSIONS: No predictor of patient delay was found among the variables collected. For one fourth of the patients, the health system delay was longer than 7 weeks. General practitioners are commonly approached first, and they have to consider TB, also for patients not considered at high-risk for TB.

Unrecognized pediatric adult-type tuberculosis puts school contacts at risk.

Adolescents with an immigrant background who are from tuberculosis high-incidence regions were at highest risk to develop adult-type tuberculosis disease in a low-incidence region during a 20-year period. If diagnosis and treatment were delayed up to 6 months, latent tuberculosis infection was detected in almost half of the affected individuals' school contacts.