T-SPOT®.TB test and clinical risk scoring for diagnosis of latent tuberculosis infection among Thai healthcare workers

Challenges and the Way forward in Diagnosis and Treatment of Tuberculosis Infection

Globally, it is estimated that one-quarter of the world's population is latently infected with Mycobacterium tuberculosis (Mtb), also known as latent tuberculosis infection (LTBI). Recently, this condition has been referred to as tuberculosis infection (TBI), considering the dynamic spectrum of the infection, as 5-10% of the latently infected population will develop active TB (ATB). The chances of TBI development increase due to close contact with index TB patients. The emergence of multidrug-resistant TB (MDR-TB) and the risk of development of latent MDR-TB has further complicated the situation. Detection of TBI is challenging as the infected individual does not present symptoms. Currently, there is no gold standard for TBI diagnosis, and the only screening tests are tuberculin skin test (TST) and interferon gamma release assays (IGRAs). However, these tests have several limitations, including the inability to differentiate between ATB and TBI, false-positive results in BCG-vaccinated individuals (only for TST), false-negative results in children, elderly, and immunocompromised patients, and the inability to predict the progression to ATB, among others. Thus, new host markers and Mtb-specific antigens are being tested to develop new diagnostic methods. Besides screening, TBI therapy is a key intervention for TB control. However, the long-course treatment and associated side effects result in non-adherence to the treatment. Additionally, the latent MDR strains are not susceptible to the current TBI treatments, which add an additional challenge. This review discusses the current situation of TBI, as well as the challenges and efforts involved in its control.

Risk factors of tuberculosis infection among health care workers: A meta-analysis

BACKGROUNDS

Health care workers (HCWs) are globally known to have high risk of tuberculosis (TB) infection while risk factors of TB infections among HCWs are still inconclusive.

OBJECTIVES

To perform a meta-analysis in effort to identify risk factors of TB infection among HCWs.

METHODS

A meta-analysis was conducted between February and July 2019. Papers were searched in Pubmed, Embase, Cochrane, and Web of science and information of interest were extracted. The correlation and effect estimation were analyzed using random or fixed effect model.

RESULTS

A total of 12 studies consisting of 2871 cases and 15,673 controls were included and six risk factors were available for meta-analysis. Cumulative calculation found that age, working duration, and types of job were significant risk factor of TB infection while gender, active TB contact, and types of workplace were not associated significantly with TB infection among HCWs. Our pooled data revealed that decreased risk of TB infection was observed in age less than 30 years (age < 30 years vs. age ≥ 30 years) and working duration less than five years (working duration < 5 years vs. ≥5 years). Being more than 40 years, working more than 10 years, and being physicians increased the risk of TB infection significantly compared to age ≤40 years, working duration ≤10 years, and other job types, respectively.

CONCLUSIONS

Our meta-analysis has identified the significant risk factors of TB infection among HCWs. Our results may be useful for establishing future TB prevention program among HCWs.