Epidemiology of the koch phenomenon of infants after bacillus calmette-Guerin vaccination by interferon-γ release assay status, Japan, 2013-2019 by Masaki Ota

Int J Mycobacteriol. 2023 Jan-Mar;12(1):43-48. doi: 10.4103/ijmy.ijmy_203_22.

ABSTRACT

BACKGROUND: The epidemiology of infants who exhibited the Koch-like phenomenon after Bacillus Calmette-Guérin vaccination and who subsequently tested positive in interferon-γ release assay (IGRA) was compared to that of those who tested negative. The reports of pediatricians on the phenomenon to the health authorities of Japan were retrieved and analyzed.

METHODS: In 2013-2019, 790 infants with such events were reported with IGRA test results available, of whom 81 (10.3%) tested positive and 709 (89.7%) negative.

RESULTS: The infants who were IGRA positive did not show an increasing trend (P = 0.06, P = 0.60), whereas those who were IGRA negative showed a significantly increasing trend (P = 0.42, P = 0.0002). The infants who were IGRA positive did not exhibit seasonality, whereas those who were IGRA negative had a higher number of cases in winter than in summer. The rates of infants who were IGRA positive per 10 million live births showed a significant correlation with the tuberculosis (TB) notification rates by prefecture (P = 0.41, P = 0.004), whereas those who were IGRA negative did not (P = 0.04, P = 0.78).

CONCLUSION: The IGRA-positive infants were distributed quite differently from those who were IGRA negative and appeared more likely to be infected with TB. Reports of pediatricians on the Koch-like phenomenon should continuously be collected as the reports reflect a risk of TB infection including TB outbreaks among infants in Japan. The reports should include IGRA test results as IGRA is more specific than tuberculin skin testing. Infants with IGRA-positive results should be followed up for 2-3 years to determine their final outcomes.

PMID:36926762 | DOI:10.4103/ijmy.ijmy_203_22