Objectives: : Interferon-gamma release assays (IGRAs) are widely used in public health practice to diagnose latent tuberculosis. During the coronavirus disease (COVID-19) pandemic and rollout of COVID-19 vaccination, it has remained unclear whether COVID-19 vaccines interfere with IGRA readouts. Methods: : We prospectively recruited healthcare workers during their annual occupational health examinations in 2021. Baseline IGRA readouts were compared with follow-up data after the participants had received two doses of COVID-19 vaccination. Results: : A total of 134 baseline IGRA-negative cases (92 with ChAdOx1 vaccine, 27 with mRNA-1273 vaccine, and 15 with heterologous vaccination) and seven baseline IGRA-positive cases were analysed. Among the baseline IGRA-negative cases, there were decreased interferon-γ concentrations over the Nil (p = 0.005) and increased Mitogen-Nil (p < 0.001) values post-vaccination. For TB2-Nil value, there was a similar trend (p = 0.057) of increase observed. Compared with the 0.35 IU/mL threshold, the baseline and follow-up readout differences were less than |±0.10| IU/mL over the TB1-Nil and TB2-Nil values in >90% baseline IGRA-negative cases. No significant readout difference was observed among baseline IGRA-positive cases. Conclusions: : COVID-19 vaccination did not change IGRA interpretation in most cases. Cases showing conversion/borderline IGRA readouts should be given special consideration.

Fuente: International Journal of Infectious Diseases
Available online 1 July 2022