Modelo matemático para la estimación del riesgo anual de infección por Mycobacterium tuberculosis considerando la reversión de la prueba cutánea de la tuberculina

Antecedentes: Se estima que una cuarta parte de la población mundial está infectada con Mycobacterium tuberculosis. El riesgo anual de infección (ARI) se calcula con la prevalencia de M.tuberculosis utilizando la prueba inmunorreactiva cutánea de la tuberculina (TST). Sin embargo, el ARI generalmente se estima asumiendo que la inmunorreactividad es persistente. Métodos: estudio de modelado matemático basado en un ejercicio teórico por Sutherland, que explora el efecto de los niveles variables de reversión de TST en la estimación del ARI. El modelo se amplió mediante el uso de tasas empíricas de reversión por edad. Luego, se aplicó el modelo para volver a estimar las ARI de encuestas publicadas, ajustando la positividad de TST observada. Resultados: Las tasas constantes de reversión de TST de más del 1% tuvieron un efecto significativo en la prevalencia de inmunorreactividad, disminuyendo la prevalencia en un 9%; tasas de reversión del 10% redujeron la prevalencia en un 55% a los 19 años. Cuando se ajustó con la reversión, el modelo mostró que las ARI reestimadas eran entre 50-450% más altas que las derivadas de las encuestas de TST. Conclusiones: La estimación de ARI sin tener en cuenta la reversión subestimará sistemáticamente el riesgo de infección verdadero.Background: Over one quarter of the global population is estimated to be infected with Mycobacterium tuberculosis. One of the key metrics is the Annual Risk of Infection (ARI), derived from M. tuberculosis prevalence data from surveys using the immunoreactive Tuberculin Skin Test (TST). However, the ARI is generally estimated using the dual assumptions of lifelong viable infection as well as persistent immunoreactivity, both of which have been challenged. The study will explore the implications of TST-reversion on ARI estimates. Methods: This mathematical modelling study is building upon an existing theoretical exercise by Ian Sutherland, exploring the effect of the varying levels of TSTreversion on the estimate of the ARI. The model was expanded by using empirically estimated age-specific TST-reversion rates, daily timesteps and cubic spline interpolation. Uncertainty was estimated by determining confidence intervals for the TST-reversion proportion. The model was then applied to manually re-estimate ARIs from published TST surveys in Vietnam (Hoa et al.) and South Africa (Wood et al.), by manually fitting observed TST-positivity. Sensitivity analyses included multiple TST-reversion rates and the use of linear interpolation for the ascertainment of TST-positive estimates. Results: Constant TST-reversion rates of over 1% had a significant effect on TST-positive prevalence decreasing prevalence by 9%; TST-reversion rates of 10% decreased prevalence by 55% by age 19. When fitted with reversion, the model showed that re-estimated ARIs were 50% to 450% higher than those derived in the TST surveys. Sensitivity analyses also produced similar results. Conclusions: Estimation of ARI from TST data without accounting for reversion will consistently underestimate the risk of infection. If we are to understand transmission, we will need to incorporate reversion into our estimates of ARI to facilitate insights into the population at-risk and cost-benefit applications

The COVID-19 Pandemic in Peru: What Went Wrong?

Despite the early adoption of a national lockdown and other restrictions, Peru has been severely impacted by the COVID-19 pandemic. Having reached a milestone of more than 1,200 deaths per one million inhabitants by February 2021, important messages can be learned from how the pandemic was handled. Possible explanations for poor outcomes are a fragmented and already overwhelmed public health sector, lack of infrastructure and specialized personnel to tackle the pandemic, and deficient leadership from health authorities

COVID-19 in Latin America and the Caribbean: Two years of the pandemic.

Worldwide, nations have struggled during the coronavirus disease 2019 (COVID-19) pandemic. However, Latin America and the Caribbean faced an unmatched catastrophic toll. As of March 2022, the region has reported approximately 15% of cases and 28% of deaths worldwide. Considering the relatively late arrival of SARS-CoV-2, several factors in the region were determinants of the humanitarian crisis that ensued. Pandemic unpreparedness, fragile healthcare systems, forthright inequalities, and poor governmental support facilitated the spread of the virus throughout the region. Moreover, reliance on repurposed and ineffective drugs such as hydroxychloroquine and ivermectin-to treat or prevent COVID-19-was publicised through misinformation and created a false sense of security and poor adherence to social distancing measures. While there were hopes that herd immunity could be achieved after the region's disastrous first peak, the emergence of the Gamma, Lambda, and Mu variants made this unattainable. This review explores how Latin America and the Caribbean fared during the first 2 years of the pandemic, and how, despite all the challenges, the region became a global leader in COVID-19 vaccination, with 63% of its population fully vaccinated

Adherence to standards of care and mortality in the management of Staphylococcus aureus bacteraemia in Peru: A prospective cohort study.

BACKGROUND: Despite high mortality rates, physicians can alter the course of the Staphylococcus aureus bacteraemia (SAB) by following recommended standards of care. We aim to assess the adherence of these guidelines and their impact on mortality. METHODS: Substudy from a prospective cohort of hospitalized patients with SAB from three hospitals from Peru. Hazard ratios were calculated using Cox proportional regression to evaluate the association between 30-day mortality and the performance of standards of care: removal of central venous catheters (CVC), follow-up blood cultures, echocardiography, correct duration, and appropriate definitive antibiotic therapy. RESULTS: 150 cases of SAB were evaluated; 61.33% were MRSA. 30-day attributable mortality was 22.39%. CVC removal was done in 42.86% of patients. Follow-up blood cultures and echocardiograms were performed in 8% and 29.33% of cases, respectively. 81.33% of cases had appropriate empirical treatment, however, only 22.41% of MSSA cases were given appropriate definitive treatment, compared to 93.47% of MRSA. The adjusted regression for all-cause mortality found a substantial decrease in hazards when removing CVC (aHR 0.28, 95% CI: 0.10 - 0.74) and instituting appropriate definitive treatment (aHR 0.27, 95% CI: 0.08 - 0.86), while adjusting for standards of care, qPitt bacteraemia score, comorbidities, and methicillin susceptibility; similar results were found in the attributable mortality model (aHR 0.24, 95% CI: 0.08 - 0.70 and aHR 0.21, 95% CI: 0.06 - 0.71, respectively). CONCLUSIONS: Deficient adherence to standards of care was observed, especially definitive treatment for MSSA. CVC removal and the use of appropriate definitive antibiotic therapy reduced the hazard mortality of SAB

Spatio-temporal co-occurrence of hotspots of tuberculosis, poverty and air pollution in Lima, Peru.

Growing evidence suggests pollution and other environmental factors have a role in the development of tuberculosis (TB), however, such studies have never been conducted in Peru. Considering the association between air pollution and specific geographic areas, our objective was to determine the spatial distribution and clustering of TB incident cases in Lima and their co-occurrence with clusters of fine particulate matter (PM2.5) and poverty. We found co-occurrences of clusters of elevated concentrations of air pollutants such as PM2.5, high poverty indexes, and high TB incidence in Lima. These findings suggest an interplay of socio-economic and environmental in driving TB incidence

Association between tuberculosis and depression on negative outcomes of tuberculosis treatment: A systematic review and meta-analysis.

BACKGROUND: Depression is a common comorbidity of tuberculosis (TB) and is associated with poor adherence to treatment of multiple disorders. We conducted a systematic review to synthesize the existing evidence on the relationship between depression and negative outcomes of TB treatment. METHODS: We systematically reviewed studies that evaluated depressive symptoms (DS) directly or indirectly through psychological distress (PD) and measured negative treatment outcomes of drug-sensitive pulmonary TB, defined as death, loss to follow-up, or non-adherence. Sources included PubMed, Global Health Library, Embase, Scopus and Web of Science from inception to August 2019. RESULTS: Of the 2,970 studies initially identified, eight articles were eligible for inclusion and two were used for the primary outcome meta-analysis. We found a strong association between DS and negative TB treatment outcomes (OR = 4.26; CI95%:2.33-7.79; I2 = 0%). DS were also associated with loss to follow-up (OR = 8.70; CI95%:6.50-11.64; I2 = 0%) and death (OR = 2.85; CI95%:1.52-5.36; I2 = 0%). Non-adherence was not associated with DS and PD (OR = 1.34; CI95%:0.70-2.72; I2 = 94.36) or PD alone (OR = 0.92; CI95%:0.81-1.05; I2 = 0%). CONCLUSIONS: DS are associated with the negative TB treatment outcomes of death and loss to follow-up. Considerable heterogeneity exists in the definition of depression and outcomes such as non-adherence across the limited number of studies on this topic