Should medical students be routinely offered BCG vaccination?

Healthy, safe and effective international medical student electives: a systematic review and recommendations for program coordinators

Background

Thousands of medical students undertake international medical electives each year. These students face potentially substantial health and safety risks as well as educational and ethical challenges and therefore should undertake their electives within well-structured and coordinated programs.

Methods

We conducted a qualitative systematic review based on a pre-determined protocol. Relevant publications and guidelines relating to international medical electives were identified through a review of the literature using on-line search engines, principally PubMed. We then conducted a systematic qualitative synthesis to extract relevant publications. Finally, the literature was organized according to themes, with the aim of developing a structured set of Recommendations for Implementation for program coordinators.

Results

A wide range of important issues were identified which were categorized into seven themes upon which recommendations were made principally for the benefit of program coordinators: Responsibilities; General policies; Travel advisories; Occupational risk assessment; Funding & finances, Pre-departure training programs; and Post-return debriefing and screening.

Conclusions

Recommendations for program coordinators on the health and safety of medical students while on international medical electives have been sourced from existing guidelines and relevant publications. There was considerable consensus from the literature and as such these synthesised recommendations could form the basis for internationally accepted standards for elective placement program coordinators.

Electronic supplementary material

The online version of this article (10.1186/s40794-019-0081-0) contains supplementary material, which is available to authorized users.

Comparison of QuantiFERON-TB Gold In-Tube Test and Tuberculin Skin Test for Identification of LatentMycobacterium tuberculosisInfection in Healthcare Staff and Association Between Positive Test Results and Known Risk Factors for Infection

Objective.

We compared a whole-blood interferon-γ release assay (QuantiFERON-TB Gold In-Tube test, hereafter “QFT-in tube test”) with a tuberculin skin test (TST) to determine which test more accurately identified latentMycobacterium tuberculosisinfection in healthcare staff.

Methods.

A total of 481 hospital staff members were recruited from 5 hospitals in Melbourne, Australia. They provided information about demographic variables and tuberculosis (TB) risk factors (ie, birth or travel in a country with a high prevalence of TB, working in an occupation likely to involve contact withM. tuberculosisor individuals with TB, or being a household contact of an individual with a proven case of pulmonary TB). The QFT-in tube test and the TST were administered in accordance with standardized protocols. Concordance between the test results and positive risk factors was analyzed using theкstatistic, the McNemar test, and logistic regression.

Results.

A total of 358 participants had both a TST result and a QFT-in tube test result available for comparison. There were fewer positive QFT-in tube test results than positive TST results (6.7% vs. 33.0%;P< .001). Agreement between the tests was poor (71%;к= 0.16). A positive QFT-in tube test result was associated with birth in a country with a high prevalence of TB, the number of years an individual had lived in a country with a high prevalence of TB (ie, the effect of each additional year, treated as a continuous variable), and high-risk occupational contact. A positive TST result was associated with older age, receipt of bacille Calmette-Guérin (BCG) vaccination, and working in an occupation that involved patient contact. Receipt of BCG vaccination was most strongly associated with discordant results in instances in which the TST result was positive and the QFT-in tube test result was negative.

Conclusion.

In a population of healthcare staff with a low prevalence of TB and a significant rate of BCG vaccination, a positive QFT-in tube test result was associated with the presence of known risk factors for TB exposure, whereas a positive TST result was more strongly associated with a prior history of BCG vaccination.

Whole blood interferon-gamma assay for baseline tuberculosis screening among Japanese healthcare students

BACKGROUND

The whole blood interferon-gamma assay (QuantiFERON-TB-2G; QFT) has not been fully evaluated as a baseline tuberculosis screening test in Japanese healthcare students commencing clinical contact. The aim of this study was to compare the results from the QFT with those from the tuberculin skin test (TST) in a population deemed to be at a low risk for infection with Mycobacterium tuberculosis.

METHODOLOGY/PRINCIPAL FINDINGS

Healthcare students recruited at Okayama University received both the TST and the QFT to assess the level of agreement between these two tests. The interleukin-10 levels before and after exposure to M tuberculosis-specific antigens (early-secreted antigenic target 6-kDa protein [ESAT-6] and culture filtrate protein 10 [CFP-10]) were also measured. Of the 536 healthcare students, most of whom had been vaccinated with bacillus-Calmette-Guérin (BCG), 207 (56%) were enrolled in this study. The agreement between the QFT and the TST results was poor, with positive result rates of 1.4% vs. 27.5%, respectively. A multivariate analysis also revealed that the induration diameter of the TST was not affected by the interferon-gamma concentration after exposure to either of the antigens but was influenced by the number of BCG needle scars (p = 0.046). The whole blood interleukin-10 assay revealed that after antigen exposure, the median increases in interleukin-10 concentration was higher in the subgroup with the small increase in interferon-gamma concentration than in the subgroup with the large increase in interferon-gamma concentration (0.3 vs. 0 pg/mL; p = 0.004).

CONCLUSIONS/SIGNIFICANCE

As a baseline screening test for low-risk Japanese healthcare students at their course entry, QFT yielded quite discordant results, compared with the TST, probably because of the low specificity of the TST results in the BCG-vaccinated population. We also found, for the first time, that the change in the interleukin-10 level after exposure to specific antigens was inversely associated with that in the interferon-gamma level in a low-risk population.