Decline of Tuberculosis Burden in Vietnam Measured by Consecutive National Surveys, 2007-2017

Multi-drug resistance and compensatory mutations in Mycobacterium tuberculosis in Vietnam

BACKGROUND

Vietnam is a hotspot for the emergence and spread of multidrug-resistant Mycobacterium tuberculosis. This study aimed to perform a retrospective study on the compensatory evolution in multidrug-resistant M. tuberculosis strains and the association with drug-resistant mutations and M. tuberculosis genotypes.

METHODS

Hundred and seventy-three strains resistant to rifampicin (n = 126) and/or isoniazid (n = 170) (multidrug-resistant = 123) were selected according to different drug-resistant patterns and genotypes. The genes/promoter regions including rpoA, rpoB, rpoC, katG, inhA, inhA promoter, ahpC, ahpC promoter, gyrA, gyrB, and rrs were sequenced for each strain.

RESULTS

Frequency of rifampicin- and isoniazid-resistant mutations in multidrug-resistant strains was 99.2% and 97.0%, respectively. Mutations associated with low -high levels of drug resistance with low- or no-fitness costs compared to the wild type, including rpoB_Ser450Leu, katG_Ser315Thr, inhA-15(A-T), gyrA_Asp94Gly, and rrs_A1401GA, accounted for 46.3%, 76.4%, 16.2%, 8.9%, and 11.4%, respectively, in the multidrug-resistant strains. Beijing and Euro-American genotype strains were associated with high-level drug-resistant mutations, rpoB_Ser450Leu, katG_Ser315Thr, and gyrA_Asp94Gly, while East African-Indian genotype strains were associated with low to high-level drug-resistant mutations, rpoB_His445Asp, rpoB_His445Tyr, inhA-15(C-T) and rrs_A1401G. Multidrug-resistant strains (19.5%) harboured compensatory mutations linked to rifampicin resistance in rpoA, rpoB, or rpoC. Notably, the frequency of compensatory mutations in Beijing genotypes was significantly higher than in East African-Indian genotypes (21.1% vs. 3.3%, OR = 7.7; 95% CI = 1.0 to 61.2, p = 0.03). The proportion of multidrug-resistant strains with rpoB_Ser450Leu mutations carrying rpoA-rpoC mutations was higher than that of strains with other rpoB mutations (OR = 5.4; 95% CI = 1.4 to 21.1, p = 0.02) and was associated with Beijing strains. Only 1.2% (2/170) isoniazid-resistant strains carried aphC-52(C-T) mutation in the promoter region of the ahpC gene, which was hypothesised to be the compensatory mutation in isoniazid-resistant strains. Meanwhile, 11 isoniazid-resistant strains carried a katG mutation combined with either inhA-8(T-C) or inhA-15(A-T) mutations and were associated with East African-Indian strains.

CONCLUSIONS

Mutations associated with high levels of drug resistance without/with low fitness costs (rpoB_Ser450Leu and katG_Ser315Thr) along with compensatory mutations linked to rifampicin resistance were strongly associated with multidrug-resistant M. tuberculosis Beijing strains in Vietnam.

Persistently high TB prevalence in Nairobi County neighbourhoods, 2015-2022

National and sub-national population-based surveys, when performed at intervals, may assess important changes in TB prevalence. In 2022 we re-surveyed nine Nairobi County neighbourhoods that were previously surveyed in 2015. We aimed to determine pulmonary TB prevalence, compare prevalence to 2015 estimates, and evaluate changes in risk groups. Participants who reported cough of any duration and/or whose chest x-ray suggested TB submitted sputum for smear microscopy, Xpert Ultra, and liquid culture. We defined prevalent TB as Mycobacterium tuberculosis detection by sputum Xpert or culture, excepting individuals who were only trace positive. Our methods differed from 2015, which used solid media, Xpert MTB/RIF, and cough duration >2 weeks. We calculated TB prevalence using random-effects logistic regression models with missing value imputations and inverse probability weighting. In 2022 among 6369 participants, 1582 submitted ≥1 sputum sample, among whom 42 (2.7%) had TB, a weighted TB prevalence of 806/100,000 (95% confidence interval (CI), 518-1096). An additional 31 (2.0%) participants tested Ultra trace-positive/culture-negative. For comparison to 2015, we excluded 2022 participants (n = 2) whose only criterion for sputum was cough <2 weeks. There was no evidence for a decline in overall TB prevalence from 2015 to 2022. TB prevalence among men was high (1301/100,000) and remained high compared to 2015 (p-value <0.05). The age group with the highest estimated prevalence remained people ages 45-54 years. Among people with prevalent TB who reported cough, 76% had not sought health care. Dissimilar from other serial surveys that showed declines in TB prevalence, we found persistently high TB prevalence over a 7-year period in Nairobi County. Limitations of this study include changes in methodology between the two surveys and complex effects of the COVID-19 pandemic.

Temporal pattern and effect of COVID-19 on the trend of TB, DRTB, paediatrics TB and TB with HIV Coinfection: A decadal trend analysis

Background

India shares 2/3 of global TB burden. MDR and HIV coinfections are the main obstacle in achieving the successful TB control because it decrease the therapy effect.

Objective

To analyze the long-term trends of incidence of tuberculosis cases and identify any differences between actual and projected cases after the COVID-19 pandemic.

Methodology

A retrolective study was conducted in SMS medical college, Jaipur, and data were extracted from state TB cell and annual report published by central TB division. A multiplicative model was used for conducting time series analysis. The projected yearly number of cases were estimated using the line of best fit based on the least square method.

Result

An increasing trend in the incidence of TB was observed, rising from 1,517,363 in 2008 to 2,404,815 in 2019. Similarly, DRTB also showed an increasing trend from 10,267 (0.67% of total new cases) in 2011 to 66,255 (2.75%) in 2019. The new cases of DRTB in 2020 were significantly lower than the projected number. The trend of HIV coinfection in TB cases fluctuated over the past decade.

Conclusion

The findings reveal a concerning upward trajectory in TB incidence and DRTB cases over the decade. The fluctuating trend in HIV coinfection in TB cases emphasizes the complexity of addressing these interconnected health challenges.

Performing national independence through medical diplomacy: tuberculosis control and socialist internationalism in Cold War Vietnam

This article explores medical diplomacy as a means of navigating distinct but related nation-building and internationalist projects during the Cold War. It examines how medical professionals from the Democratic Republic of Vietnam (DRV) utilized their expertise to bolster foreign relations and assert national independence. This article focuses on how three tuberculosis (TB) specialists - Đặng Đức Trạch, Phạm Ngọc Thạch and Phạm Khắc Quảng - adopted, adapted and circulated techniques of TB control, including a modified version of bacillus Calmette-Guérin (BCG) vaccine. Amidst these endeavours, these medical-doctors-cum-diplomats navigated various forms of internationalism while soliciting medical assistance. Their roles within the DRV's state apparatus were prominently showcased from the 1950s to the 1970s, particularly at international gatherings such as the conferences of Ministers of Health of the Socialist Countries (MOHOSC). Because of the political complexities inherent in socialist internationalism, these conferences provided a crucial platform for dialogue among socialist nations when other avenues were limited. Consequently, the DRV's medical experts cultivated goodwill and garnered political support, despite encountering mixed results in their TB control initiatives.

Laparoscopic surgery for the diagnosis of abdominal effusion in the modern era of imaging - a retrospective study in a low-to-middle-income country

Intraperitoneal ascites is a consequence or combination of many different underlying diseases. Laparoscopy with peritoneal biopsy is a tool for rapid and accurate diagnosis.

Methods

We retrospectively identified patients who could not be diagnosed by clinical examination, laboratory investigations, and imaging tests.

Results

A total of 103 (55 male and 48 female) patients were selected. The median age of the study group was 54 years (range 38-64 years). Typical clinical symptoms included fever (58.2%), abdominal pain (56.3%), and digestive disorders (62.1%). Fever and digestive disorders were higher in the peritoneal tuberculosis (TB) group than in the metastatic cancer group [(62.1% vs. 12.5%, P=0.009) and (66.3% vs. 12.5%, P=0.004)]. Abdominal pain was more common in the metastatic cancer group than in the other groups (100% vs. 55.8%, P=0.020). Patients in the TB and chronic inflammation groups had lower red blood cell counts and blood albumin (41 vs. 42, P=0.039) than those in the metastatic cancer group, respectively. The rate of intestinal wall thickening on ultrasound and peritoneal thickening on computed tomography was higher in the cancer group than in the benign group (87.5% vs. 7.4%, P=0.000) (75% vs. 23.2%, P=0.005), respectively. There was no difference in the median peritoneal fluid volume between the two groups (390 vs. 340, P=0.058). Pathological results showed 88.3%, 7.8%, and 3.9% of peritoneal TB, metastatic cancer, and chronic inflammatory lesions, respectively. The median hospital stay did not differ between the two groups (4 vs. 3 days, P=0.051). Both groups of patients had no morbidity or mortality.

Conclusion

Unidentified ascites and peritonitis must be difficult for making diagnose by conventional methods. Laparoscopy might be supportive of making a rapid diagnosis and starting early treatment.

A geospatial platform to support visualization, analysis, and prediction of tuberculosis notification in space and time

Background

Tuberculosis has caused significant public health and economic burdens in Vietnam over the years. The Vietnam National Tuberculosis Program is facing considerable challenges in its goal to eliminate tuberculosis by 2030, with the COVID-19 pandemic having negatively impacted routine tuberculosis services at all administrative levels. While the turnaround time of tuberculosis infection may delay disease detection, high transportation frequency could potentially mislead epidemiological studies. This study was conducted to develop an online geospatial platform to support healthcare workers in performing data visualization and promoting the active case surveillance in community as well as predicting the TB incidence in space and time.

Method

This geospatial platform was developed using tuberculosis notification data managed by The Vietnam National Tuberculosis Program. The platform allows case distribution to be visualized by administrative level and time. Users can retrieve epidemiological measurements from the platform, which are calculated and visualized both temporally and spatially. The prediction model was developed to predict the TB incidence in space and time.

Results

An online geospatial platform was developed, which presented the prediction model providing estimates of case detection. There were 400,370 TB cases with bacterial evidence to be included in the study. We estimated that the prevalence of TB in Vietnam was at 414.67 cases per 100.000 population. Ha Noi, Da Nang, and Ho Chi Minh City were predicted as three likely epidemiological hotspots in the near future.

Conclusion

Our findings indicate that increased efforts should be undertaken to control tuberculosis transmission in these hotspots.

Social determinants of the changing tuberculosis prevalence in Việt Nam: Analysis of population-level cross-sectional studies

BACKGROUND

An ecological relationship between economic development and reduction in tuberculosis prevalence has been observed. Between 2007 and 2017, Việt Nam experienced rapid economic development with equitable distribution of resources and a 37% reduction in tuberculosis prevalence. Analysing consecutive prevalence surveys, we examined how the reduction in tuberculosis (and subclinical tuberculosis) prevalence was concentrated between socioeconomic groups.

METHODS AND FINDINGS

We combined data from 2 nationally representative Việt Nam tuberculosis prevalence surveys with provincial-level measures of poverty. Data from 94,156 (2007) and 61,763 (2017) individuals were included. Of people with microbiologically confirmed tuberculosis, 21.6% (47/218) in 2007 and 29.0% (36/124) in 2017 had subclinical disease. We constructed an asset index using principal component analysis of consumption data. An illness concentration index was estimated to measure socioeconomic position inequality in tuberculosis prevalence. The illness concentration index changed from -0.10 (95% CI -0.08, -0.16; p = 0.003) in 2007 to 0.07 (95% CI 0.06, 0.18; p = 0.158) in 2017, indicating that tuberculosis was concentrated among the poorest households in 2007, with a shift towards more equal distribution between rich and poor households in 2017. This finding was similar for subclinical tuberculosis. We fitted multilevel models to investigate relationships between change in tuberculosis prevalence, individual risks, household socioeconomic position, and neighbourhood poverty. Controlling for provincial poverty level reduced the difference in prevalence, suggesting that changes in neighbourhood poverty contribute to the explanation of change in tuberculosis prevalence. A limitation of our study is that while tuberculosis prevalence surveys are valuable for understanding socioeconomic differences in tuberculosis prevalence in countries, given that tuberculosis is a relatively rare disease in the population studied, there is limited power to explore socioeconomic drivers. However, combining repeated cross-sectional surveys with provincial deprivation estimates during a period of remarkable economic growth provides valuable insights into the dynamics of the relationship between tuberculosis and economic development in Việt Nam.

CONCLUSIONS

We found that with equitable economic growth and a reduction in tuberculosis burden, tuberculosis became less concentrated among the poor in Việt Nam.