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1.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-332878

ABSTRACT

Objective To examine if SARS-CoV-2 infections vary by vaccination status, if an individual had previously tested positive and by neighbourhood socioeconomic deprivation across the Delta and Omicron epidemic waves of SARS-CoV-2. Design Cohort study using electronic health records Setting Cheshire and Merseyside, England (3 rd June 2021 to 1 st March 2022) Participants 2.7M residents Main Outcome measure Registered positive test for SARS-CoV-2 Results Social inequalities in registered positive tests were dynamic during the study. Originally higher SARS-CoV-2 rates in the most socioeconomically deprived neighbourhoods changed to being higher in the least deprived neighbourhoods from the 1 st September 2021. While the introduction of Omicron initially reset inequalities, they continued to be dynamic and inconsistent. Individuals who were fully vaccinated (two doses) were associated with fewer registered positive tests (e.g., between 1 st September and 27 th November 2021: (i) individuals engaged in testing – Hazards Ratio (HR) = 0.48, 95% Confidence Intervals (CIs) = 0.47-0.50;(ii) individuals engaged with healthcare - HR = 0.34, 95% CIs = 0.33-0.34). Individuals with a previous registered positive test were also less likely to have a registered positive test (e.g., between 1 st September and 27 th November 2021: (i) individuals engaged in testing - HR = 0.16, 95% CIs = 0.15-0.18;(ii) individuals engaged with healthcare - HR = 0.14, 95% CIs = 0.13-0.16). However, Omicron is disrupting these associations due to immune escape resulting in smaller effect sizes for both measures. Conclusions Changing patterns of SARS-CoV-2 infections during the Delta and Omicron waves reveals a dynamic pandemic that continues to affect diverse communities in sometimes unexpected ways.

2.
BMC Infect Dis ; 22(1): 270, 2022 Mar 20.
Article in English | MEDLINE | ID: covidwho-1745481

ABSTRACT

BACKGROUND: From January to May 2021 the alpha variant (B.1.1.7) of SARS-CoV-2 was the most commonly detected variant in the UK. Following this, the Delta variant (B.1.617.2) then became the predominant variant. The UK COVID-19 vaccination programme started on 8th December 2020. Prior to the Delta variant, most vaccine effectiveness studies focused on the alpha variant. We therefore aimed to estimate the effectiveness of the BNT162b2 (Pfizer-BioNTech) and the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines in preventing symptomatic and asymptomatic infection with respect to the Delta variant in a UK setting. METHODS: We used anonymised public health record data linked to infection data (PCR) using the Combined Intelligence for Population Health Action resource. We then constructed an SIR epidemic model to explain SARS-CoV-2 infection data across the Cheshire and Merseyside region of the UK. Vaccines were assumed to be effective after 21 days for 1 dose and 14 days for 2 doses. RESULTS: We determined that the effectiveness of the Oxford-AstraZeneca vaccine in reducing susceptibility to infection is 39% (95% credible interval [34, 43]) and 64% (95% credible interval [61, 67]) for a single dose and a double dose respectively. For the Pfizer-BioNTech vaccine, the effectiveness is 20% (95% credible interval [10, 28]) and 84% (95% credible interval [82, 86]) for a single-dose and a double dose respectively. CONCLUSION: Vaccine effectiveness for reducing susceptibility to SARS-CoV-2 infection shows noticeable improvement after receiving two doses of either vaccine. Findings also suggest that a full course of the Pfizer-BioNTech provides the optimal protection against infection with the Delta variant. This reinforces the need to complete the full course programme to maximise individual protection and reduce transmission.


Subject(s)
COVID-19 , Viral Vaccines , COVID-19/prevention & control , COVID-19 Vaccines , Humans , SARS-CoV-2/genetics
3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-323234

ABSTRACT

Background: SARS-CoV-2 is frequently shed in the stool of patients hospitalised with COVID-19. The rate of faecal shedding of SARS-CoV-2 among individuals in the community, and its potential to contribute to spread of disease, is unknown. Methods: In this prospective, observational cohort study among households in Liverpool, UK, participants underwent weekly nasal/throat swabbing to detect SARS-CoV-2 virus, over a 12-week period from enrolment starting July 2020. Participants that tested positive for SARS-CoV-2 were asked to provide a stool sample three and 14 days later. In addition, in October and November 2020, during a period of high community transmission, stool sampling was undertaken to determine the prevalence of SARS-CoV-2 faecal shedding among all study participants. SARS-CoV-2 RNA was detected using Real-Time PCR. Findings: A total of 434 participants from 176 households were enrolled. Eighteen participants (4·2%: 95% confidence interval [CI] 2·5-6·5%) tested positive for SARS-CoV-2 virus on nasal/throat swabs and of these, 3/17 (18%: 95% CI 4-43%) had SARS-CoV-2 detected in stool. Two of three participants demonstrated ongoing faecal shedding of SARS-CoV-2 , without associated gastrointestinal symptoms, after testing negative for SARS-CoV-2 in respiratory samples. Among 165/434 participants without SARS-CoV-2 infection and who took part in the prevalence study, none had detectable SARS-CoV-2 in stool. There was no demonstrable household transmission of SARS-CoV-2 among households containing a participant with faecal shedding. Interpretation: Faecal shedding of SARS-CoV-2 occurred among participants in the community with confirmed SARS-CoV-2 infection. However, during a period of high community transmission, faecal shedding of SARS-CoV-2 was not detected among participants without SARS-CoV-2 infection. It is unlikely that the faecal-oral route plays a significant role in household and community transmission of SARS-CoV-2 . Funding: NIHR Health Protection Research Unit (HPRU) in Gastrointestinal Infections, NIHR HPRU in Emerging and Zoonotic Infections, Centre of Excellence in Infectious Disease Research, and Alder Hey Charity.Declaration of Interest: NF reports research grant support from the Alder Hey Charity. MIG reports other financial or non-financial interests in V-PLEX Th17 Panel 1 Human Kit. LT reports research grant support from NIHR HPRU in Emerging and Zoonotic Infections related to this study. Unrelated to this study LT also reports fees paid to University of Liverpool from Eisai for providing a lecture on COVID-19 and cancer. WS reports scholarship for doctoral study at the University of Liverpool from the Ministry of Finance, Republic of Indonesia through the Indonesia Endowment Fund for Education program. DH, NAC, ERA, TS, KS and NMV have nothing to disclose.Ethical Approval: The study has received approval from the NHS Research Ethics Committee;REC Reference: 20/HRA/2297, IRAS Number: 283464.

4.
PLoS One ; 16(11): e0250541, 2021.
Article in English | MEDLINE | ID: covidwho-1496343

ABSTRACT

BACKGROUND: A year following the onset of the COVID-19 pandemic, new infections and deaths continue to increase in Europe. Serological studies, through providing evidence of past infection, can aid understanding of the population dynamics of SARS-CoV-2 infection. OBJECTIVES: This systematic review of SARS-CoV-2 seroprevalence studies in Europe was undertaken to inform public health strategies including vaccination, that aim to accelerate population immunity. METHODS: We searched the databases Web of Science, MEDLINE, EMBASE, SCOPUS, Cochrane Database of Systematic Reviews and grey literature sources for studies reporting seroprevalence of SARS-CoV-2 antibodies in Europe published between 01/12/2019-30/09/20. We provide a narrative synthesis of included studies. Studies were categorized into subgroups including healthcare workers (HCWs), community, outbreaks, pregnancy and children/school. Due to heterogeneity in other subgroups, we only performed a random effects meta-analysis of the seroprevalence amongst HCWs stratified by their country. RESULTS: 115 studies were included spanning 17 European countries, that estimated the seroprevalence of SARS-CoV-2 from samples obtained between November 2019 -August 2020. A total of 54/115 studies included HCWs with a reported seroprevalence among HCWs ranging from 0.7% to 45.3%, which did not differ significantly by country. In community studies significant heterogeneity was reported in the seroprevalence between different age groups and the majority of studies reported there was no significant difference by gender. CONCLUSION: This review demonstrates a wide heterogeneity in reported seroprevalence of SARS-CoV-2 antibodies between populations. Continued evaluation of seroprevalence is required to understand the impact of public health measures and inform interventions including vaccination programmes.


Subject(s)
COVID-19/epidemiology , COVID-19/immunology , COVID-19/prevention & control , Europe/epidemiology , Humans , Pandemics , Public Health , Seroepidemiologic Studies
5.
BMJ : British Medical Journal (Online) ; 374, 2021.
Article in English | ProQuest Central | ID: covidwho-1495284

ABSTRACT

Rigorous studies of these vaccines in action are an urgent priority globally

6.
BMC Infect Dis ; 21(1): 784, 2021 Aug 09.
Article in English | MEDLINE | ID: covidwho-1350139

ABSTRACT

BACKGROUND: SARS-CoV-2 is frequently shed in the stool of patients hospitalised with COVID-19. The extent of faecal shedding of SARS-CoV-2 among individuals in the community, and its potential to contribute to spread of disease, is unknown. METHODS: In this prospective, observational cohort study among households in Liverpool, UK, participants underwent weekly nasal/throat swabbing to detect SARS-CoV-2 virus, over a 12-week period from enrolment starting July 2020. Participants that tested positive for SARS-CoV-2 were asked to provide a stool sample three and 14 days later. In addition, in October and November 2020, during a period of high community transmission, stool sampling was undertaken to determine the prevalence of SARS-CoV-2 faecal shedding among all study participants. SARS-CoV-2 RNA was detected using Real-Time PCR. RESULTS: A total of 434 participants from 176 households were enrolled. Eighteen participants (4.2%: 95% confidence interval [CI] 2.5-6.5%) tested positive for SARS-CoV-2 virus on nasal/throat swabs and of these, 3/17 (18%: 95% CI 4-43%) had SARS-CoV-2 detected in stool. Two of three participants demonstrated ongoing faecal shedding of SARS-CoV-2, without gastrointestinal symptoms, after testing negative for SARS-CoV-2 in respiratory samples. Among 165/434 participants without SARS-CoV-2 infection and who took part in the prevalence study, none had SARS-CoV-2 in stool. There was no demonstrable household transmission of SARS-CoV-2 among households containing a participant with faecal shedding. CONCLUSIONS: Faecal shedding of SARS-CoV-2 occurred among community participants with confirmed SARS-CoV-2 infection. However, during a period of high community transmission, faecal shedding of SARS-CoV-2 was not detected among participants without SARS-CoV-2 infection. It is unlikely that the faecal-oral route plays a significant role in household and community transmission of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Cohort Studies , Humans , Prospective Studies , RNA, Viral , United Kingdom/epidemiology , Virus Shedding
7.
BMJ Open ; 11(3): e048317, 2021 03 17.
Article in English | MEDLINE | ID: covidwho-1140339

ABSTRACT

INTRODUCTION: The emergence and rapid spread of COVID-19 have caused widespread and catastrophic public health and economic impact, requiring governments to restrict societal activity to reduce the spread of the disease. The role of household transmission in the population spread of SARS-CoV-2, and of host immunity in limiting transmission, is poorly understood. This paper describes a protocol for a prospective observational study of a cohort of households in Liverpool City Region, UK, which addresses the transmission of SARS-CoV-2 between household members and how immunological response to the infection changes over time. METHODS AND ANALYSIS: Households in the Liverpool City Region, in which members have not previously tested positive for SARS-CoV-2 with a nucleic acid amplification test, are followed up for an initial period of 12 weeks. Participants are asked to provide weekly self-throat and nasal swabs and record their activity and presence of symptoms. Incidence of infection and household secondary attack rates of COVID-19 are measured. Transmission of SARS-CoV-2 will be investigated against a range of demographic and behavioural variables. Blood and faecal samples are collected at several time points to evaluate immune responses to SARS-CoV-2 infection and prevalence and risk factors for faecal shedding of SARS-CoV-2, respectively. ETHICS AND DISSEMINATION: The study has received approval from the National Health Service Research Ethics Committee; REC Reference: 20/HRA/2297, IRAS Number: 283 464. Results will be disseminated through scientific conferences and peer-reviewed open access publications. A report of the findings will also be shared with participants. The study will quantify the scale and determinants of household transmission of SARS-CoV-2. Additionally, immunological responses before and during the different stages of infection will be analysed, adding to the understanding of the range of immunological response by infection severity.


Subject(s)
COVID-19/epidemiology , COVID-19/immunology , COVID-19/transmission , Humans , Observational Studies as Topic , Prospective Studies , Research Design , State Medicine , United Kingdom/epidemiology
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