Burden of multidrug-resistant tuberculosis in England: a focus on prevalent cases.

The incidence of multidrug-resistant tuberculosis (MDR-TB) is routinely reported by the Public Health England, UK, but prevalence better represents burden. To estimate MDR-TB prevalence, and identify the factors associated with acquired resistance and unsuccessful outcomes in people managed by the health services. We included notified MDR-TB cases prevalent between 2010 and 2014. Multivariable logistic regression was used to identify the factors associated with acquisition of resistance and unsuccessful outcomes. The social risk factors (SRFs) recorded were alcohol, drug misuse, homelessness and incarceration. Between 2010 and 2014, there were 2.3-3.1 times more prevalent than incident cases each year, with an increasing prevalence-to-incidence ratio over time; 86% of prevalent cases were foreign-born, and 15% had an SRF. Overall, 11% of MDR-TB cases acquired resistance, including 18% of those with SRFs and 22% of UK-born MDR-TB cases acquired resistance. Half of the cases completed treatment by 24 months; those with SRFs, extensive drug resistance or acquired resistance were less likely to complete treatment. The number of prevalent cases is higher than incident cases, and increases over time, so a focus on prevalent cases enables better planning for services to support patients. We recommend that additional support be provided for those at risk of acquiring resistance, including those with SRFs. .

Public health outcome of Tuberculosis Cluster Investigations, England 2010-2013.

OBJECTIVES: Tuberculosis (TB) is a serious re-emergent public health problem in the UK. In response to rising case incidence a National TB Strain-Typing Service based on molecular strain-typing was established. This facilitates early detection and investigation of clusters, targeted public health action, and prevention of further transmission. We review the added public health value of investigating molecular TB strain-typed (ST) clusters. METHODS: A structured questionnaire for each ST cluster investigated in England between 1 January 2010 and 30 June 2013 was completed. Questions related to epidemiological links and public health action and the perceived benefits of ST cluster investigation. RESULTS: There were 278 ST cluster investigations (CIs) involving 1882 TB cases. Cluster size ranged from 2 to 92. CIs identified new epidemiological links in 36% of clusters; in 18% STs were discordant refuting transmission thought to have occurred. Additional public health action was taken following 23% of CI. CONCLUSIONS: We found positive benefits of TB molecular ST and CI, in identifying new epidemiological links between cases and taking public health action and in refuting transmission and saving resources. This needs to be translated to a decrease in transmission to provide evidence of public health value in this low prevalence high resource setting.

Delay from symptom onset to treatment start among tuberculosis patients in England, 2012-2015.

Improving access to tuberculosis (TB) care and ensuring early diagnosis are two major aims of the WHO End TB strategy and the Collaborative TB Strategy for England. This study describes risk factors associated with diagnostic delay among TB cases in England. We conducted a retrospective cohort study of TB cases notified to the Enhanced TB Surveillance System in England between 2012 and 2015. Diagnostic delay was defined as more than 4 months between symptom onset and treatment start date. Multivariable logistic regression was used to identify demographic and clinical factors associated with diagnostic delay. Between 2012 and 2015, 22 422 TB cases were notified in England and included in the study. A third (7612) of TB cases had a diagnostic delay of more than 4 months. Being female, aged 45 years and older, residing outside of London and having extra-pulmonary TB disease were significantly associated with a diagnostic delay in the multivariable model (aOR = 1.2, 1.2, 1.2, 1.3, 1.8, respectively). This study identifies demographic and clinical factors associated with diagnostic delay, which will inform targeted interventions to improve access to care and early diagnosis among these groups, with the ultimate aim of helping reduce transmission and improve treatment outcomes for TB cases in England.

The challenge of estimating tuberculosis mortality accurately in England and Wales.

BACKGROUND: Accurate estimates of tuberculosis (TB) mortality are required to monitor progress towards the World Health Organization End TB goal of reducing TB deaths by 95% by 2035. We compared TB death data for England and Wales from the national surveillance system (Enhanced Tuberculosis Surveillance System [ETS]) and the vital registration system from the Office for National Statistics (ONS). METHODS: TB cases notified in ETS were matched to deaths in ONS (dONS) with International Classification of Diseases, Tenth Revision (ICD-10) codes indicating that TB caused/contributed to the death (A15-A19). Deaths captured in one but not both systems were assessed to identify if ONS captured all TB deaths and if there was under-notification of TB in ETS. We stratified deaths into active TB, TB sequelae, incidental deaths and not TB. RESULTS: Between 2005 and 2015, there were fewer deaths in ETS (dETS) than dONS with ICD-10 codes A15-A19 (n = 4207 vs. n = 6560); 57% of dETS were recorded as dONS and 53% of dONS were notified to ETS. A total of 9289 deaths were identified from dETS and dONS: 64% were due to active TB, 23% were TB sequelae, 6% were incidental and 7% were not TB. CONCLUSIONS: TB deaths in ETS and ONS differ substantially. Almost one third of TB deaths recorded by ONS are not due to active TB; this can be amended through coding changes.

Investigating a tuberculosis cluster among Filipino health care workers in a low-incidence country.

SETTING: Nearly 8% of adult tuberculosis (TB) cases in England, Wales and Northern Ireland (EW&NI) occur among health care workers (HCWs), the majority of whom are from high TB incidence countries. OBJECTIVES: To determine if a TB cluster containing multiple HCWs was due to nosocomial transmission. METHODS: A cluster of TB cases notified in EW&NI from 2009 to 2014, with indistinguishable 24-locus mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) profiles, was identified through routine national cluster review. Cases were investigated to identify epidemiological links, and occupational health (OH) information was collected for HCW cases. To further discriminate strains, typing of eight additional loci was conducted. RESULTS: Of the 53 cases identified, 22 were HCWs. The majority (n = 43), including 21 HCWs, were born in the Philippines. Additional typing split the cluster into three subclusters and seven unique strains. No epidemiological links were identified beyond one household and a common residential area. HCWs in this cluster received no or inadequate OH assessment. CONCLUSIONS: The MIRU-VNTR profile of this cluster probably reflects common endemic strains circulating in the Philippines, with reactivation occurring in the UK. Furthermore, 32-locus typing showed that 24-locus MIRU-VNTR failed to distinguish strain diversity. The lack of OH assessment indicates that latent tuberculous infection could have been identified and treated, thereby preventing active cases from occurring.