ABSTRACT
PurposeThe Gamma variant of SARS-CoV-2, first detected in travellers from Brazil, was found to have high transmissibility and virulence; following this finding, this paper aims to describe the epidemiology of Gamma cases in England from its first detection on 12 February 2021 to 31 August 2021. MethodsThe demographic analysis of Gamma cases was stratified by travel exposure. Travel-associated cases were further analysed by countries travelled from, stratified by categories set in place by the Red (highest risk countries), Amber, Green (lowest risk countries) travel policy, which was implemented from May to October 2021. ResultsThere were 251 confirmed Gamma cases detected in England in the study period. 35.1% were imported, 5.6% were secondary, and 29.5% were not travel associated. Early cases were predominantly travel-associated, with later cases likely obtained through community transmission. 51.0% of travel-related cases were travellers from Amber countries, and 40.2% had at least one Red country in their journey. ConclusionThe Gamma variant has not seen the same expansion as other variants such as Delta, most likely due to Delta out-competing community transmission of Gamma. Findings indicate the travel policy requiring quarantine for Red and Amber list travellers may have also contributed to preventing onward transmission of Gamma.
ABSTRACT
BackgroundThe SARS-CoV-2 Omicron variant (B.1.1.529) has rapidly replaced the Delta variant (B.1.617.2) to become dominant in England. This epidemiological study assessed differences in transmissibility between the Omicron and Delta using two methods and data sources. MethodsOmicron and Delta cases were identified through genomic sequencing, genotyping and S-gene target failure in England from 5-11 December 2021. Secondary attack rates for Omicron and Delta using named contacts and household clustering were calculated using national surveillance and contact tracing data. We used multivariable logistic regression was used to control for factors associated with transmission. FindingsAnalysis of contact tracing data identified elevated secondary attack rates for Omicron vs Delta in household (15.0% vs 10.8%) and non-household (8.2% vs 3.7%) settings. The proportion of index cases resulting in residential clustering was twice as high for Omicron (16.1%) compared to Delta (7.3%). Transmission was significantly less likely from cases, or in named contacts, in receipt of three compared to two vaccine doses in household settings, but less pronounced for Omicron (aRR 0.78 and 0.88) compared to Delta (aRR 0.62 and 0.68). In non-household settings, a similar reduction was observed for Delta cases and contacts (aRR 0.84 and 0.51) but only for Omicron contacts (aRR 0.76, 95% CI: 0.58-0.93) and not cases in receipt of three vs two doses (aRR 0.95, 0.77-1.16). InterpretationOur study identified increased risk of onward transmission of Omicron, consistent with its successful global displacement of Delta. We identified a reduced effectiveness of vaccination in lowering risk of transmission, a likely contributor for the rapid propagation of Omicron. FundingStudy funded by the UK Health Security Agency.
ABSTRACT
We describe gender-based differences in a community-wide TB screening programme in Karachi, Pakistan, in which 311 732 individuals were screened in mobile camps using symptom questionnaires and van-mounted digital chest X-ray, between 1 January 2018 and 31 December 2019. Only 22.4% (69 869) of camp attendees were women. Female attendees were less likely to have sputum collected and tested (31.5% (95% CI 30.4% to 32.7%) vs 38.5% (95% CI 37.6% to 39.1%)) or to initiate TB treatment (75.9% (95% CI 68.1% to 82.6%) vs 82.8% (95% CI 78.9% to 86.2%)), when indicated. Among the participants, the age-standardised prevalence of active TB was higher among women (prevalence ratio 1.4, 95% CI 1.1 to 1.7). These findings underscore the importance of integrating gender into the design and monitoring of TB screening programmes to ensure that women and men benefit equally from this important intervention.
Subject(s)
Mycobacterium tuberculosis , Tuberculosis, Pulmonary , Female , Humans , Male , Mass Screening , Pakistan/epidemiology , Prevalence , Sputum , Tuberculosis, Pulmonary/diagnosis , Tuberculosis, Pulmonary/epidemiologyABSTRACT
BackgroundHousehold transmission has been demonstrated to be an important factor in the population-level growth of COVID-19. UK Health Security Agency (UKHSA) maintains data on positive tests for COVID-19 and the residential addresses of cases. We sought to use this information to characterise clusters of COVID-19 in multi-generational households in England. MethodsUsing cross-sectional design, cases of COVID-19 were assigned to clusters if they occurred in the same residential property in a 14-day rolling window. Patient demographic data were supplemented with reference to the ONS index of multiple deprivation and population density. Multi-generational households were defined as a cluster with at least three people, with one case in a person who was 0-16 years old and one case in a person who was [≥] 60 years old, with at least 16 years between two members of each age group. ResultsA total of 3,647,063 COVID-19 cases were reported between 01 April 2020 and 20 May 2021. Of these, 1,980,527 (54.3 %) occurred in residential clusters. Multi-generational households formed 1.5 % of clusters, with these more likely to occur in areas of higher population density and higher relative deprivation. Multi-generational clusters were more common among households of non-White ethnicity and formed larger clusters than non-multi-generational clusters (median cluster size 6, IQR 4-11 vs 3, IQR 3-4, respectively). ConclusionMulti-generational clusters were not highly prevalent in England during the study period, however were more common in certain populations. BOX TEXTO_ST_ABSWhat is already known on this subjectC_ST_ABSGreater risk of infection with SARS-CoV-2 in England is associated with being of non-White ethnicity, residence in an area of greater deprivation and higher population density. What is less clear is the role of household composition in the risk of COVID-19 transmission. It has been hypothesised that multi-generational housing (in which at least three different generations are resident in the same property) accounted for a substantial proportion of COVID-19 cases. We sought to test this hypothesis. What this study addsThis study provides descriptive evidence around the role of multi-generational households in the COVID-19 pandemic in England between April 2020 and March 2021. It does not support the hypothesis that this period (a period of low incidence in England), a substantial proportion of COVID-19 cases occurred in multi-generational households.
