Household clustering of SARS-CoV-2 variant of concern B.1.1.7 (VOC-202012–01) in England

Chudasama, Dimple; Flannagan, Joe; Collin, Simon M.; Charlett, André; Twohig, Katherine A.; Lamagni, Theresa; Dabrera, Gavin

doi:10.1016/j.jinf.2021.04.029

Cited by 16 publications

(21 citation statements)

References 4 publications

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“…Cases who were able to effectively isolate may have avoided transmitting the infection to other household members, as previous studies have suggested [29], but were more likely to be re-exposed to SARS-CoV-2 at a later point. Increased odds of quarantine were also observed as the year progressed, supporting earlier ndings of increased transmissibility of the Alpha variant, rst detected in the UK in November 2020 and the predominant lineage by February 2021 [31,32].…”

Section: Discussionsupporting

confidence: 77%

Differential Impact of Quarantine Policies for Recovered COVID-19 Cases in England: A Case Cohort Study of Surveillance Data, June to December 2020

Merrick¹,

Chudasama²,

Flannagan³

et al. 2022

Preprint

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Background From 12th March 2020, individuals in England were advised to quarantine in their home if a household member tested positive for SARS-CoV-2. A mandatory isolation period of 10 days was introduced on 28th September 2020 and applied to all individuals with COVID-19. We assessed the frequency, timing, and characteristics of recovered COVID-19 cases requiring subsequent quarantine episodes due to household re-exposure. Methods In this case cohort study, all laboratory-confirmed COVID-19 cases notified in England (29th June to 28th December 2020) were analysed to identify consecutive household case(s). Multivariable logistic regression was used to determine associations between case characteristics and need to quarantine following recent infection (within 28 days of diagnosis). Results Among 1,651,550 cases resident in private dwellings and Houses of Multiple Occupancy (HMOs), 56,179 (3.4%) were succeeded by further household cases diagnosed within 11–28 days of their diagnosis. Of 1,641,412 cases arising in private homes, the likelihood of further household cases was highest for Bangladeshi (aOR = 2.20, 95% CI = 2.10–2.31) and Pakistani (aOR = 2.15, 95% CI = 2.08–2.22) individuals compared to White British, as well as among young people (17-24y vs. 25-64y; aOR = 1.19, 95% CI = 1.16–1.22), men (vs. women; aOR = 1.06, 95% CI = 1.04–1.08), London residents (vs. Yorkshire and Humber; aOR = 1.57, 95% CI = 1.52–1.63) and areas of high deprivation (IMD 1 vs. 10; aOR = 1.13, 95% CI = 1.09–1.19). Conclusions Policies requiring quarantine on re-exposure of recently recovered cases differentially impact some of the most disadvantaged populations. Quarantine exemption for individuals recently (< 28 days) recovered from COVID-19 could mitigate the socioeconomic impact of the pandemic.

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Section: Discussionsupporting

confidence: 77%

Differential Impact of Quarantine Policies for Recovered COVID-19 Cases in England: A Case Cohort Study of Surveillance Data, June to December 2020

Merrick¹,

Chudasama²,

Flannagan³

et al. 2022

Preprint

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“…Previous emerging SARS-CoV-2 variants, Alpha and Delta, resulted in surges in incidence in England, with increased household clustering observed for both these variants. 9-11 In contrast, Beta and Gamma variants had lesser impact on case numbers after their emergence. 8…”

Section: Introductionmentioning

confidence: 93%

“…8 Previous emerging SARS-CoV-2 variants, Alpha and Delta, resulted in surges in incidence in England, with increased household clustering observed for both these variants. [9][10][11] In contrast, Beta and Gamma variants had lesser impact on case numbers after their emergence. 8 We applied two different methods (secondary attack rate estimates, household clustering) to assess the transmissibility of the emerging SARS-CoV-2 Omicron variant compared to the Delta variant at a time when both variants were circulating in England.…”

Section: Introductionmentioning

confidence: 94%

Comparative transmission of SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants and the impact of vaccination: national cohort study, England

Allen¹,

Tessier²,

Turner³

et al. 2022

Preprint

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Background The 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. Methods Omicron 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. Logistic regression was used to control for factors associated with transmission. Findings Analysis 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). Interpretation Our 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.

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“…A total of 37 studies reporting on public health measures in relation to VOC were included after screening. The majority of included studies reported on the Alpha VOC (n=32) 24–54. The majority of studies were conducted in Europe (n=12),24 29 30 34 35 39 40 44 47 51 53 55 followed by the UK (n=9),26 28 32 33 36 42 45 50 56 USA (n=9),25 37 38 41 43 48 49 54 57 Brazil (n=3),58–60 Canada (n=1),31 South Africa (n=1),27 Israel (n=1)46 and Japan (n=1)52 (figure 2).…”

Section: Resultsmentioning

confidence: 99%

“…The majority of included studies reported on the Alpha VOC (n=32) 24–54. The majority of studies were conducted in Europe (n=12),24 29 30 34 35 39 40 44 47 51 53 55 followed by the UK (n=9),26 28 32 33 36 42 45 50 56 USA (n=9),25 37 38 41 43 48 49 54 57 Brazil (n=3),58–60 Canada (n=1),31 South Africa (n=1),27 Israel (n=1)46 and Japan (n=1)52 (figure 2). Additional details of each study can be found in the online supplemental material 2.…”

Section: Resultsmentioning

confidence: 99%

Public health implications of SARS-CoV-2 variants of concern: a rapid scoping review

et al. 2021

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ObjectivesThe four SARS-CoV-2 variants of concern (VOC; Alpha, Beta, Gamma and Delta) identified by May 2021 are highly transmissible, yet little is known about their impact on public health measures. We aimed to synthesise evidence related to public health measures and VOC.DesignA rapid scoping review.Data sourcesOn 11 May 2021, seven databases (MEDLINE, Embase, the Cochrane Database of Systematic Reviews, Central Register of Controlled Trials, Epistemonikos’ L-OVE on COVID-19, medRxiv, bioRxiv) were searched for terms related to VOC, public health measures, transmission and health systems. No limit was placed on date of publication.Eligibility criteriaStudies were included if they reported on any of the four VOCs and public health measures, and were available in English. Only studies reporting on data collected after October 2020, when the first VOC was reported, were included.Data extraction and synthesisTitles, abstracts and full-text articles were screened by two independent reviewers. Data extraction was completed by two independent reviewers using a standardised form. Data synthesis and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines.ResultsOf the 37 included studies, the majority assessed the impact of Alpha (n=32) and were conducted in Europe (n=12) or the UK (n=9). Most were modelling studies (n=28) and preprints (n=28). The majority of studies reported on infection control measures (n=17), followed by modifying approaches to vaccines (n=13), physical distancing (n=6) and either mask wearing, testing or hand washing (n=2). Findings suggest an accelerated vaccine rollout is needed to mitigate the spread of VOC.ConclusionsThe increased severity of VOC requires proactive public health measures to control their spread. Further research is needed to strengthen the evidence for continued implementation of public health measures in conjunction with vaccine rollout. With no studies reporting on Delta, there is a need for further research on this and other emerging VOC on public health measures.

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Household clustering of SARS-CoV-2 variant of concern B.1.1.7 (VOC-202012–01) in England

Cited by 16 publications

References 4 publications

Differential Impact of Quarantine Policies for Recovered COVID-19 Cases in England: A Case Cohort Study of Surveillance Data, June to December 2020

Differential Impact of Quarantine Policies for Recovered COVID-19 Cases in England: A Case Cohort Study of Surveillance Data, June to December 2020

Comparative transmission of SARS-CoV-2 Omicron (B.1.1.529) and Delta (B.1.617.2) variants and the impact of vaccination: national cohort study, England

Public health implications of SARS-CoV-2 variants of concern: a rapid scoping review

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