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1.
Epidemiol Infect ; 150: e109, 2022 May 24.
Article in English | MEDLINE | ID: covidwho-1860261

ABSTRACT

The duration of immunity after first severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the extent to which prior immunity prevents reinfection is uncertain and remains an important question within the context of new variants. This is a retrospective population-based matched observational study where we identified the first polymerase chain reaction (PCR) positive of primary SARS-CoV-2 infection case tests between 1 March 2020 and 30 September 2020. Each case was matched by age, sex, upper tier local authority of residence and testing route to one individual testing negative in the same week (controls) by PCR. After a 90-day pre-follow-up period for cases and controls, any subsequent positive tests up to 31 December 2020 and deaths within 28 days of testing positive were identified, this encompassed an essentially vaccine-free period. We used a conditional logistic regression to analyse the results. There were 517 870 individuals in the matched cohort with 2815 reinfection cases and 12 098 first infections. The protective effect of a prior SARS-CoV-2 PCR-positive episode was 78% (odds ratio (OR) 0.22, 0.21-0.23). Protection rose to 82% (OR 0.18, 0.17-0.19) after a sensitivity analysis excluded 933 individuals with a first test between March and May and a subsequent positive test between June and September 2020. Amongst individuals testing positive by PCR during follow-up, reinfection cases had 77% lower odds of symptoms at the second episode (adjusted OR 0.23, 0.20-0.26) and 45% lower odds of dying in the 28 days after reinfection (adjusted OR 0.55, 0.42-0.71). Prior SARS-CoV-2 infection offered protection against reinfection in this population. There was some evidence that reinfections increased with the alpha variant compared to the wild-type SARS-CoV-2 variant highlighting the importance of continued monitoring as new variants emerge.


Subject(s)
COVID-19 , Reinfection , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , Cohort Studies , Humans , Polymerase Chain Reaction , Reinfection/epidemiology , Reinfection/prevention & control , Retrospective Studies , SARS-CoV-2/genetics
2.
Sex Transm Infect ; 2021 Jun 30.
Article in English | MEDLINE | ID: covidwho-1854399

ABSTRACT

OBJECTIVES: Although hepatitis B virus (HBV) vaccination for high-risk groups including gay, bisexual and other men who have sex with men (MSM) is recommended in the UK, data on HBV immunisation coverage are limited. This study aimed to understand the prevalence of HBV infection, susceptibility and immunity due to immunisation among a high-risk population of MSM and heterosexuals who are less likely to attend sexual health services. METHODS: Residual HIV-negative serology samples archived from a national HIV self-sampling service in 2016 were tested for HBV markers using an unlinked anonymous approach. Prevalence of HBV infection, evidence of immunisation and susceptibility were calculated and stratified by individuals' characteristics. Multinomial logistic regression was used to estimate relative risk ratios (RRRs) associated with covariates. RESULTS: Of 2172 samples tested, 1497 (68.9%) were from MSM and 657 (30.2%) were from heterosexuals. Susceptibility to HBV infection was 66.1% among MSM and 77.0% among heterosexuals. Only 29.9% of MSM and 17.4% of heterosexuals had serological evidence of immunisation. Current infection was 1.1% in heterosexuals and 0.2% in MSM. Adjusted analysis showed evidence of immunisation was lower among heterosexuals (RRR 0.66, 95% CI 0.50 to 0.86) and those with no previous HIV test (RRR 0.41, 95% CI 0.31 to 0.54), and higher in those of other white or other ethnicity. CONCLUSIONS: Among MSM and heterosexual users of a self-sampling HIV service, evidence of immunisation to HBV infection was low and susceptibility to infection was comparatively high, suggesting suboptimal delivery of HBV immunisation in sexual health services.

3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-333008

ABSTRACT

Importance Predictive models can help identify SARS-CoV-2 patients at greatest risk of post-COVID sequelae and direct them towards appropriate care. Objective To develop and internally validate a model to predict children and young people most likely to experience at least one impairing physical symptom 3 months after a SARS-CoV-2 PCR-test and to determine whether the impact of these predictors differed by SARS-CoV-2 infection status. Design Potential pre-specified predictors included: SARS-CoV-2 status, sex, age, ethnicity, deprivation, quality of life/functioning (5 EQ-5D-Y items), physical and mental health, and loneliness (all prior to SARS-CoV-2 testing), and number of physical symptoms at testing. Logistic regression was used to develop the model. Model performance was assessed using calibration and discrimination measures;internal validation was performed via bootstrapping;the final model was adjusted for overfitting. Setting National cohort study of SARS-CoV-2 PCR-positive and PCR-negative participants matched according to age, sex, and geographical area. Participants Children and young people aged 11-17 years who were tested for SARS-CoV-2 infection in England, January to March 2021. Main outcome measure one or more physical symptom 3 months after initial PCR-testing which affected physical, mental or social well-being and interfered with daily living. Results A total of 50,836 children and young people were approached;7,096 (3,227 test-positives, 3,869 test-negatives) who completed a questionnaire 3 months after their PCR-test were included. 39.6% (1,279/3,227) of SAR-CoV-2 PCR-positives and 30.6% (1,184/3,869) of SAR-CoV-2 PCR-negatives had at least one impairing physical symptom 3 months post-test. The final model contained predictors: SARS-COV-2 status, number of symptoms at testing, sex, age, ethnicity, self-rated physical and mental health, feelings of loneliness and four EQ-5D-Y items before testing. Internal validation showed minimal overfitting with excellent calibration and discrimination measures (optimism adjusted calibration slope:0.97527;C-statistic:0.83640). Conclusions and relevance We developed a risk prediction equation to identify those most at risk of experiencing at least one impairing physical symptom 3 months after a SARS-CoV-2 PCR-test which could serve as a useful triage and management tool for children and young people during the ongoing pandemic. External validation is required before large-scale implementation. Key Points Question Which children have impairing physical symptoms during the COVID-19 pandemic? Findings Using data from a large national matched cohort study in children and young people (CYP) aged 11-17 years (N=7,096), we developed a prediction model for experiencing at least one impairing physical symptom 3 months after testing for SARS-COV-2. Our model had excellent predictive ability, calibration and discrimination;we used it to produce a risk estimation calculator. Meaning Our developed risk calculator could serve as a useful tool in the early identification and management of CYP at risk of persisting physical symptoms in the context of the COVID-19 pandemic.

4.
Lancet Child Adolesc Health ; 6(6): 384-392, 2022 06.
Article in English | MEDLINE | ID: covidwho-1764066

ABSTRACT

BACKGROUND: Reinfection after primary SARS-CoV-2 infection is uncommon in adults, but little is known about the risks, characteristics, severity, or outcomes of reinfection in children. We aimed to assess the risk of SARS-CoV-2 reinfection in children and compare this with the risk in adults, by analysis of national testing data for England. METHODS: In our prospective, national surveillance study to assess reinfection of SARS-CoV-2 in children in England, we used national SARS-CoV-2 testing data to estimate the risk of reinfection at least 90 days after primary infection from Jan 27, 2020, to July, 31, 2021, which encompassed the alpha (B.1.1.7) and delta (B.1.617.2) variant waves in England. Data from children up to age 16 years who met the criteria for reinfection were included. Disease severity was assessed by linking reinfection cases to national hospital admission data, intensive care admission, and death registration datasets. FINDINGS: Reinfection rates closely followed community infection rates, with a small peak during the alpha wave and a larger peak during the delta wave. In children aged 16 years and younger, 688 418 primary infections and 2343 reinfections were identified. The overall reinfection rate was 66·88 per 100 000 population, which was higher in adults (72·53 per 100 000) than children (21·53 per 100 000). The reinfection rate after primary infection was 0·68% overall, 0·73% in adults compared with 0·18% in children age younger than 5 years, 0·24% in those aged 5-11 years, and 0·49% in those aged 12-16 years. Of the 109 children admitted to hospital with reinfection, 78 (72%) had comorbidities. Hospital admission rates were similar for the first (64 [2·7%] of 2343) and second episode (57 [2·4%] of 2343) and intensive care admissions were rare (seven children for the first episode and four for reinfections). There were 44 deaths within 28 days after primary infection (0·01%) and none after reinfection. INTERPRETATION: The risk of SARS-CoV-2 reinfection is strongly related to exposure due to community infection rates, especially during the delta variant wave. Children had a lower risk of reinfection than did adults, but reinfections were not associated with more severe disease or fatal outcomes. FUNDING: UK Health Security Agency.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , COVID-19/epidemiology , COVID-19 Testing , Child , England/epidemiology , Humans , Prospective Studies , Reinfection
5.
Emerg Infect Dis ; 28(3): 739-742, 2022 03.
Article in English | MEDLINE | ID: covidwho-1703458

ABSTRACT

Since the coronavirus disease pandemic response began in March 2020, tests, vaccinations, diagnoses, and treatment initiations for sexual health, HIV, and viral hepatitis in England have declined. The shift towards online and outreach services happened rapidly during 2020 and highlights the need to evaluate the effects of these strategies on health inequalities.


Subject(s)
COVID-19 , HIV Infections , Hepatitis, Viral, Human , Sexually Transmitted Diseases , England/epidemiology , HIV Infections/diagnosis , HIV Infections/epidemiology , Hepatitis, Viral, Human/epidemiology , Hepatitis, Viral, Human/therapy , Humans , Pandemics/prevention & control , SARS-CoV-2 , Sexually Transmitted Diseases/epidemiology
6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-322075

ABSTRACT

Introduction: We describe post-COVID symptomatology in a national sample of 11-17-year-old children and young people (CYP) with PCR-confirmed SARS-CoV-2 infection compared to test-negative controls. Methods: and analysis: A cohort study of test-positive (n=3,065) and age-, sex- and geographically-matched test-negative CYP (n=3,739) completed detailed questionnaires 3 months post-test. Results: At PCR-testing, 35.4% of test-positives and 8.3% of test-negatives had any symptoms whilst 30.6% and 6.2%, respectively, had 3+ symptoms. At 3 months post-testing, 66.5% of test-positives and 53.3% of test-negatives had any symptoms, whilst 30.3% and 16.2%, respectively, had 3+ symptoms. Latent class analysis identified two classes, characterised by “few” or “multiple” symptoms. This latter class was more frequent among test-positives, females, older CYP and those with worse pre-test physical and mental health. Discussion: Test-positive CYP had a similar symptom profile to test-negative CYP but with higher prevalence of single and, particularly, multiple symptoms at PCR-testing and 3 months later.

7.
J Infect ; 84(4): 542-550, 2022 04.
Article in English | MEDLINE | ID: covidwho-1683338

ABSTRACT

OBJECTIVE: We aimed to look at the burden of disease caused by SARS-COV-2 reinfections and identified potential risk factors for disease severity. METHODS: We used national surveillance data to collect information on all SARS-CoV-2 primary infection and suspected reinfection cases between January 2020 until early May 2021. Reinfection cases were positive COVID-19 PCR or antigen test, 90 days after their first COVID-19 positive test. We collected information on case demographics, hospital and ICU admission, immunisation status and if individuals were at risk of complication for COVID-19. RESULTS: Deaths reported within 28 days of testing positive were 61% (95% confidence interval: 56% to 65%) lower in suspected COVID-19 reinfection than primary infection cases. In the unvaccinated cohort, reinfections were associated with 49% (37% to 58%) lower odds of hospital admission in cases aged 50 to 65 years in the population not identified at risk of complication for COVID-19, and 34% (17% to 48%) in those at risk. ICU admission at reinfection compared to primary infection decreased 76% (55% to 87%). Individuals at risk and those aged below 50 years, who received at least 1 dose of vaccine against COVID-19, were 62% (39% to 74%) and 58% (24% to 77%) less likely to get admitted to hospital at reinfection, respectively. CONCLUSION: Prior SARS-CoV-2 infection was associated with lower odds of dying, and both prior infection and immunisation showed a protective effect against severe disease in selected populations. Older age, sex and underlying comorbidities appeared as principal risk factors for illness severity at reinfection. FUNDING: PHE/UKHSA.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , COVID-19 Vaccines , Humans , Reinfection/epidemiology , Severity of Illness Index
8.
Lancet Child Adolesc Health ; 6(4): 230-239, 2022 04.
Article in English | MEDLINE | ID: covidwho-1671374

ABSTRACT

BACKGROUND: We describe post-COVID symptomatology in a non-hospitalised, national sample of adolescents aged 11-17 years with PCR-confirmed SARS-CoV-2 infection compared with matched adolescents with negative PCR status. METHODS: In this national cohort study, adolescents aged 11-17 years from the Public Health England database who tested positive for SARS-CoV-2 between January and March, 2021, were matched by month of test, age, sex, and geographical region to adolescents who tested negative. 3 months after testing, a subsample of adolescents were contacted to complete a detailed questionnaire, which collected data on demographics and their physical and mental health at the time of PCR testing (retrospectively) and at the time of completing the questionnaire (prospectively). We compared symptoms between the test-postive and test-negative groups, and used latent class analysis to assess whether and how physical symptoms at baseline and at 3 months clustered among participants. This study is registered with the ISRCTN registry (ISRCTN 34804192). FINDINGS: 23 048 adolescents who tested positive and 27 798 adolescents who tested negative between Jan 1, 2021, and March 31, 2021, were contacted, and 6804 adolescents (3065 who tested positive and 3739 who tested negative) completed the questionnaire (response rate 13·4%). At PCR testing, 1084 (35·4%) who tested positive and 309 (8·3%) who tested negative were symptomatic and 936 (30·5%) from the test-positive group and 231 (6·2%) from the test-negative group had three or more symptoms. 3 months after testing, 2038 (66·5%) who tested positive and 1993 (53·3%) who tested negative had any symptoms, and 928 (30·3%) from the test-positive group and 603 (16·2%) from the test-negative group had three or more symptoms. At 3 months after testing, the most common symptoms among the test-positive group were tiredness (1196 [39·0%]), headache (710 [23·2%]), and shortness of breath (717 [23·4%]), and among the test-negative group were tiredness (911 [24·4%]), headache (530 [14·2%]), and other (unspecified; 590 [15·8%]). Latent class analysis identified two classes, characterised by few or multiple symptoms. The estimated probability of being in the multiple symptom class was 29·6% (95% CI 27·4-31·7) for the test-positive group and 19·3% (17·7-21·0) for the test-negative group (risk ratio 1·53; 95% CI 1·35-1·70). The multiple symptoms class was more frequent among those with positive PCR results than negative results, in girls than boys, in adolescents aged 15-17 years than those aged 11-14 years, and in those with lower pretest physical and mental health. INTERPRETATION: Adolescents who tested positive for SARS-CoV-2 had similar symptoms to those who tested negative, but had a higher prevalence of single and, particularly, multiple symptoms at the time of PCR testing and 3 months later. Clinicians should consider multiple symptoms that affect functioning and recognise different clusters of symptoms. The multiple and varied symptoms show that a multicomponent intervention will be required, and that mental and physical health symptoms occur concurrently, reflecting their close relationship. FUNDING: UK Department of Health and Social Care, in their capacity as the National Institute for Health Research, and UK Research and Innovation.


Subject(s)
COVID-19/complications , COVID-19/diagnosis , COVID-19/epidemiology , Adolescent , COVID-19/pathology , COVID-19/psychology , COVID-19 Testing , Child , Cohort Studies , England/epidemiology , Female , Humans , Male , Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Surveys and Questionnaires
9.
J Infect ; 84(5): 692-700, 2022 05.
Article in English | MEDLINE | ID: covidwho-1665191

ABSTRACT

BACKGROUND: There are limited data on immune responses to heterologous COVID-19 immunisation schedules, especially following an extended ≥12-week interval between doses. METHODS: SARS-CoV-2 infection-naïve and previously-infected adults receiving ChAd-BNT (ChAdOx1 nCoV-19, AstraZeneca followed by BNT162b2, Pfizer-BioNTech) or BNT-ChAd as part of the UK national immunisation programme provided blood samples at 30 days and 12 weeks after their second dose. Geometric mean concentrations (GMC) of anti-SARS-CoV-2 spike (S-antibody) and nucleoprotein (N-antibody) IgG antibodies and geometric mean ratios (GMR) were compared with a contemporaneous cohort receiving homologous ChAd-ChAd or BNT-BNT. RESULTS: During March-October 2021, 75,827 individuals were identified as having received heterologous vaccination, 9,489 invited to participate, 1,836 responded (19.3%) and 656 were eligible. In previously-uninfected adults, S-antibody GMC at 30 days post-second dose were lowest for ChAd-ChAd (862 [95% CI, 694 - 1069]) and significantly higher for ChAd-BNT (6233 [5522-7035]; GMR 6.29; [5.04-7.85]; p<0.001), BNT-ChAd (4776 [4066-5610]; GMR 4.55 [3.56-5.81]; p<0.001) and BNT-BNT (5377 [4596-6289]; GMR 5.66 [4.49-7.15]; p<0.001). By 12 weeks after dose two, S-antibody GMC had declined in all groups and remained significantly lower for ChAd-ChAd compared to ChAd-BNT (GMR 5.12 [3.79-6.92]; p<0.001), BNT-ChAd (GMR 4.1 [2.96-5.69]; p<0.001) and BNT-BNT (GMR 6.06 [4.32-8.50]; p<0.001). Previously infected adults had higher S-antibody GMC compared to infection-naïve adults at all time-points and with all vaccine schedules. CONCLUSIONS: These real-world findings demonstrate heterologous schedules with adenoviral-vector and mRNA vaccines are highly immunogenic and may be recommended after a serious adverse reaction to one vaccine product, or to increase programmatic flexibility where vaccine supplies are constrained.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibody Formation , COVID-19/prevention & control , COVID-19 Vaccines , England , Humans , Immunoglobulin G , Vaccination
10.
N Engl J Med ; 386(4): 340-350, 2022 01 27.
Article in English | MEDLINE | ID: covidwho-1621313

ABSTRACT

BACKGROUND: Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), have been used since December 2020 in the United Kingdom. Real-world data have shown the vaccines to be highly effective against Covid-19 and related severe disease and death. Vaccine effectiveness may wane over time since the receipt of the second dose of the ChAdOx1-S (ChAdOx1 nCoV-19) and BNT162b2 vaccines. METHODS: We used a test-negative case-control design to estimate vaccine effectiveness against symptomatic Covid-19 and related hospitalization and death in England. Effectiveness of the ChAdOx1-S and BNT162b2 vaccines was assessed according to participant age and status with regard to coexisting conditions and over time since receipt of the second vaccine dose to investigate waning of effectiveness separately for the B.1.1.7 (alpha) and B.1.617.2 (delta) variants. RESULTS: Vaccine effectiveness against symptomatic Covid-19 with the delta variant peaked in the early weeks after receipt of the second dose and then decreased by 20 weeks to 44.3% (95% confidence interval [CI], 43.2 to 45.4) with the ChAdOx1-S vaccine and to 66.3% (95% CI, 65.7 to 66.9) with the BNT162b2 vaccine. Waning of vaccine effectiveness was greater in persons 65 years of age or older than in those 40 to 64 years of age. At 20 weeks or more after vaccination, vaccine effectiveness decreased less against both hospitalization, to 80.0% (95% CI, 76.8 to 82.7) with the ChAdOx1-S vaccine and 91.7% (95% CI, 90.2 to 93.0) with the BNT162b2 vaccine, and death, to 84.8% (95% CI, 76.2 to 90.3) and 91.9% (95% CI, 88.5 to 94.3), respectively. Greater waning in vaccine effectiveness against hospitalization was observed in persons 65 years of age or older in a clinically extremely vulnerable group and in persons 40 to 64 years of age with underlying medical conditions than in healthy adults. CONCLUSIONS: We observed limited waning in vaccine effectiveness against Covid-19-related hospitalization and death at 20 weeks or more after vaccination with two doses of the ChAdOx1-S or BNT162b2 vaccine. Waning was greater in older adults and in those in a clinical risk group.


Subject(s)
COVID-19/prevention & control , Adolescent , Adult , Age Factors , Aged , COVID-19/mortality , COVID-19/virology , Case-Control Studies , Female , Hospitalization/statistics & numerical data , Humans , Immunization, Secondary , Immunogenicity, Vaccine , Male , Middle Aged , Patient Acuity , Risk Factors , SARS-CoV-2 , Time Factors , United Kingdom/epidemiology
11.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-297070

ABSTRACT

Background: There are limited data on immune responses to heterologous COVID–19 immunisation schedules, especially following an extended ≥12–week interval between doses. Methods: SARS–CoV–2 infection–naïve and previously–infected adults receiving ChAd–BNT (ChAdOx1 nCoV–19, AstraZeneca followed by BNT162b2, Pfizer–BioNTech) or BNT–ChAd as part of the UK national immunisation programme provided blood samples at 30 days and 12 weeks after their second dose. Geometric mean concentrations (GMC) of anti–SARS–CoV–2 spike (S-antibody) and nucleoprotein (N-antibody) IgG antibodies and geometric mean ratios (GMR) were compared with a contemporaneous cohort receiving homologous ChAd–ChAd or BNT–BNT. Results: During March–October 2021, 75,827 individuals were identified as having received heterologous vaccination, 9,489 invited to participate, 1,836 responded (19.3%) and 656 were eligible. In previously–uninfected adults, S–antibody GMC at 30 days post–second dose were lowest for ChAd–ChAd (862 (95%CI, 694– 1069)) and significantly higher for ChAd–BNT (6233 (5522– 7035);GMR 6.29;(5.04– 7.85);p<0.001), BNT-ChAd (4776 (4066– 5610);GMR 4.55 (3.56– 5.81);p<0.001) and BNT–BNT (5377 (4596– 6289);GMR 5.66 (4.49– 7.15);p<0.001). By 12 weeks after dose two, S–antibody GMC had declined in all groups and remained significantly lower for ChAd–ChAd compared to ChAd–BNT (GMR 5.12 (3.79– 6.92);p<0.001), BNT–ChAd (GMR 4.1 (2.96– 5.69);p<0.001) and BNT–BNT (GMR 6.06 (4.32– 8.50);p<0.001). Previously infected adults had higher S–antibody GMC compared to infection–naïve adults at all time–points and with all vaccine schedules. Conclusions: These real–world findings demonstrate heterologous schedules with adenoviral–vector and mRNA vaccines are highly immunogenic and may be recommended after a serious adverse reaction to one vaccine product, or to increase programmatic flexibility where vaccine supplies are constrained.

12.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296846

ABSTRACT

Background Reinfection after primary SARS-CoV-2 infection is uncommon in adults, but little is known about the risks, characteristics, severity or outcomes of reinfection in children. Methods We used national SARS-CoV-2 testing data in England to estimate the risk of reinfection ≥90 days after primary infection from 01 January 2020 to 31 July 2021, which encompassed both the Alpha and Delta waves in England. Disease severity was assessed by linking reinfection cases to national hospitalisation, intensive care admission and death registrations datasets. Findings Reinfection rates closely followed community infection rates, with a small peak during the Alpha wave and a larger peak during the Delta wave. In children aged ≤16 years, there were 688,418 primary infections and 2,343 reinfections. The overall reinfection rate was 66·88/100,000 population, being higher in adults (72.53/100,000) than in children (21·53/100,000). Reinfection rates after primary infection were 0·68% overall, 0·73% in adults and 0·34% in children. Of the 109 reinfections in children admitted to hospital, 78 (72%) had underlying comorbidities. Hospitalisation rates were similar for the first (64/2343, 2·73%) and second episode (57/2343, 2·43%). Intensive care admission was rare after primary infection (n=7) or reinfection (n=4), mainly in children with comorbidities. 44 deaths occurred after primary infection within 28 days of diagnosis (44/688,418, 0·01%), none after possible reinfections. Interpretation The risk of SARS-CoV-2 reinfection is strongly related to exposure due to community infection rates, especially during the Delta variant wave. Children had a lower risk of reinfection than adults, but reinfections were not associated with more severe disease or fatal outcomes. Funding PHE/UKHSA Research in Context Evidence Before this study We searched PubMed with the terms “COVID-19” or “SARS-CoV-2” with “reinfection” to identify publications relating to SARS-CoV-2 reinfections from 01 January until 15 November 2021. There were few publications relating to SARS-CoV-2 reinfections, and these primarily related to adults. Published studies reported very low rates of reinfection during the first few months after primary infection in adults. COVID-19 vaccines provide effective immune protection against SARS-CoV-2 infection, but recent studies have reported increasing risk of breakthrough infection with time since primary vaccination due to waning immunity. Several SARS-CoV-2 variants, including the beta, gamma and delta variants have been shown to partially evade immunity after natural infection and vaccination, potentially increasing the risk of reinfections and breakthrough infections, respectively. Data on reinfections in children are lacking and restricted mainly to case reports in immunocompromised children. Added Value of This Study We used national SARS-CoV-2 testing data during the first 19 months of the pandemic to estimate the risk of reinfection in children compared to adults during a period that encompassed both the Alpha and the Delta variant waves in England. We found that the risk of reinfection correlated with the risk of SARS-CoV-2 exposure and therefore, closely reflected community infection rates, with most reinfections occurring during the Delta variant wave. Whilst acknowledging the limitation of using national testing data, we found that children had a lower risk of reinfection compared to adults and that the risk of reinfection in children increased with age. Reinfections were not associated with severe disease in terms of hospitalization or intensive care admission and there were no fatalities within 28 days of the reinfection episode in children. Implications of all the Available Evidence SARS-CoV-2 reinfections are rare in children, especially younger children, and occurred mainly during the Delta wave in England. Reinfections were not associated with more severe disease or fatal outcomes in children. COVID-19 vaccinati n will provide further protection against primary infections and reinfections in children.

13.
BMJ Open ; 11(8): e052838, 2021 08 26.
Article in English | MEDLINE | ID: covidwho-1376511

ABSTRACT

INTRODUCTION: There is uncertainty surrounding the diagnosis, prevalence, phenotype, duration and treatment of Long COVID. This study aims to (A) describe the clinical phenotype of post-COVID symptomatology in children and young people (CYP) with laboratory-confirmed SARS-CoV-2 infection compared with test-negative controls, (B) produce an operational definition of Long COVID in CYP, and (C) establish its prevalence in CYP. METHODS AND ANALYSIS: A cohort study of SARS-CoV-2-positive CYP aged 11-17 years compared with age, sex and geographically matched SARS-CoV-2 test-negative CYP. CYP aged 11-17 testing positive and negative for SARS-CoV-2 infection will be identified and contacted 3, 6, 12 and 24 months after the test date. Consenting CYP will complete an online questionnaire. We initially planned to recruit 3000 test positives and 3000 test negatives but have since extended our target. Data visualisation techniques will be used to examine trajectories over time for symptoms and variables measured repeatedly, separately by original test status. Summary measures of fatigue and mental health dimensions will be generated using dimension reduction methods such as latent variables/latent class/principal component analysis methods. Cross-tabulation of collected and derived variables against test status and discriminant analysis will help operationalise preliminary definitions of Long COVID. ETHICS AND DISSEMINATION: Research Ethics Committee approval granted. Data will be stored in secure Public Health England servers or University College London's Data Safe Haven. Risks of harm will be minimised by providing information on where to seek support. Results will be published on a preprint server followed by journal publication, with reuse of articles under a CC BY licence. Data will be published with protection against identification when there are small frequencies involved. TRIAL REGISTRATION NUMBER: ISRCTN34804192; Pre-results.


Subject(s)
COVID-19 , Adolescent , COVID-19/complications , Child , Cohort Studies , Humans , Prevalence , SARS-CoV-2
14.
N Engl J Med ; 385(7): 585-594, 2021 08 12.
Article in English | MEDLINE | ID: covidwho-1319062

ABSTRACT

BACKGROUND: The B.1.617.2 (delta) variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), has contributed to a surge in cases in India and has now been detected across the globe, including a notable increase in cases in the United Kingdom. The effectiveness of the BNT162b2 and ChAdOx1 nCoV-19 vaccines against this variant has been unclear. METHODS: We used a test-negative case-control design to estimate the effectiveness of vaccination against symptomatic disease caused by the delta variant or the predominant strain (B.1.1.7, or alpha variant) over the period that the delta variant began circulating. Variants were identified with the use of sequencing and on the basis of the spike (S) gene status. Data on all symptomatic sequenced cases of Covid-19 in England were used to estimate the proportion of cases with either variant according to the patients' vaccination status. RESULTS: Effectiveness after one dose of vaccine (BNT162b2 or ChAdOx1 nCoV-19) was notably lower among persons with the delta variant (30.7%; 95% confidence interval [CI], 25.2 to 35.7) than among those with the alpha variant (48.7%; 95% CI, 45.5 to 51.7); the results were similar for both vaccines. With the BNT162b2 vaccine, the effectiveness of two doses was 93.7% (95% CI, 91.6 to 95.3) among persons with the alpha variant and 88.0% (95% CI, 85.3 to 90.1) among those with the delta variant. With the ChAdOx1 nCoV-19 vaccine, the effectiveness of two doses was 74.5% (95% CI, 68.4 to 79.4) among persons with the alpha variant and 67.0% (95% CI, 61.3 to 71.8) among those with the delta variant. CONCLUSIONS: Only modest differences in vaccine effectiveness were noted with the delta variant as compared with the alpha variant after the receipt of two vaccine doses. Absolute differences in vaccine effectiveness were more marked after the receipt of the first dose. This finding would support efforts to maximize vaccine uptake with two doses among vulnerable populations. (Funded by Public Health England.).


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunogenicity, Vaccine , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/epidemiology , COVID-19/virology , Case-Control Studies , Female , Humans , Male , Middle Aged , Treatment Outcome , United Kingdom/epidemiology , Vaccine Potency , Young Adult
15.
Euro Surveill ; 26(28)2021 07.
Article in English | MEDLINE | ID: covidwho-1315940

ABSTRACT

Adults receiving heterologous COVID-19 immunisation with mRNA (Comirnaty) or adenoviral-vector (Vaxzevria) vaccines had higher reactogenicity rates and sought medical attention more often after two doses than homologous schedules. Reactogenicity was higher among ≤ 50 than > 50 year-olds, women and those with prior symptomatic/confirmed COVID-19. Adults receiving heterologous schedules on clinical advice after severe first-dose reactions had lower reactogenicity after dose 2 following Vaxzevria/Comirnaty (93.4%; 95% confidence interval: 90.5-98.1 vs 48% (41.0-57.7) but not Comirnaty/Vaxzevria (91.7%; (77.5-98.2 vs 75.0% (57.8-87.9).


Subject(s)
COVID-19 Vaccines , COVID-19 , Adult , England/epidemiology , Female , Humans , SARS-CoV-2 , Vaccination
17.
BMJ ; 373: n1088, 2021 05 13.
Article in English | MEDLINE | ID: covidwho-1228861

ABSTRACT

OBJECTIVE: To estimate the real world effectiveness of the Pfizer-BioNTech BNT162b2 and Oxford-AstraZeneca ChAdOx1-S vaccines against confirmed covid-19 symptoms (including the UK variant of concern B.1.1.7), admissions to hospital, and deaths. DESIGN: Test negative case-control study. SETTING: Community testing for covid-19 in England. PARTICIPANTS: 156 930 adults aged 70 years and older who reported symptoms of covid-19 between 8 December 2020 and 19 February 2021 and were successfully linked to vaccination data in the National Immunisation Management System. INTERVENTIONS: Vaccination with BNT162b2 or ChAdOx1-S. MAIN OUTCOME MEASURES: Primary outcomes were polymerase chain reaction confirmed symptomatic SARS-CoV-2 infections, admissions to hospital for covid-19, and deaths with covid-19. RESULTS: Participants aged 80 years and older vaccinated with BNT162b2 before 4 January 2021 had a higher odds of testing positive for covid-19 in the first nine days after vaccination (odds ratio up to 1.48, 95% confidence interval 1.23 to 1.77), indicating that those initially targeted had a higher underlying risk of infection. Vaccine effectiveness was therefore compared with the baseline post-vaccination period. Vaccine effects were noted 10 to 13 days after vaccination, reaching a vaccine effectiveness of 70% (95% confidence interval 59% to 78%), then plateauing. From 14 days after the second dose a vaccination effectiveness of 89% (85% to 93%) was found compared with the increased baseline risk. Participants aged 70 years and older vaccinated from 4 January (when ChAdOx1-S delivery commenced) had a similar underlying risk of covid-19 to unvaccinated individuals. With BNT162b2, vaccine effectiveness reached 61% (51% to 69%) from 28 to 34 days after vaccination, then plateaued. With ChAdOx1-S, effects were seen from 14 to 20 days after vaccination, reaching an effectiveness of 60% (41% to 73%) from 28 to 34 days, increasing to 73% (27% to 90%) from day 35 onwards. On top of the protection against symptomatic disease, a further 43% (33% to 52%) reduced risk of emergency hospital admission and 51% (37% to 62%) reduced risk of death was observed in those who had received one dose of BNT162b2. Participants who had received one dose of ChAdOx1-S had a further 37% (3% to 59%) reduced risk of emergency hospital admission. Follow-up was insufficient to assess the effect of ChAdOx1-S on mortality. Combined with the effect against symptomatic disease, a single dose of either vaccine was about 80% effective at preventing admission to hospital with covid-19 and a single dose of BNT162b2 was 85% effective at preventing death with covid-19. CONCLUSION: Vaccination with either one dose of BNT162b2 or ChAdOx1-S was associated with a significant reduction in symptomatic covid-19 in older adults, and with further protection against severe disease. Both vaccines showed similar effects. Protection was maintained for the duration of follow-up (>6 weeks). A second dose of BNT162b2 was associated with further protection against symptomatic disease. A clear effect of the vaccines against the B.1.1.7 variant was found.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Hospitalization/statistics & numerical data , Vaccination/methods , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19/immunology , COVID-19/mortality , COVID-19 Testing/methods , COVID-19 Vaccines/immunology , Case-Control Studies , England/epidemiology , Female , Humans , Male , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Treatment Outcome , Vaccination/statistics & numerical data
18.
Euro Surveill ; 26(11)2021 03.
Article in English | MEDLINE | ID: covidwho-1181332

ABSTRACT

BackgroundA multi-tiered surveillance system based on influenza surveillance was adopted in the United Kingdom in the early stages of the coronavirus disease (COVID-19) epidemic to monitor different stages of the disease. Mandatory social and physical distancing measures (SPDM) were introduced on 23 March 2020 to attempt to limit transmission.AimTo describe the impact of SPDM on COVID-19 activity as detected through the different surveillance systems.MethodsData from national population surveys, web-based indicators, syndromic surveillance, sentinel swabbing, respiratory outbreaks, secondary care admissions and mortality indicators from the start of the epidemic to week 18 2020 were used to identify the timing of peaks in surveillance indicators relative to the introduction of SPDM. This timing was compared with median time from symptom onset to different stages of illness and levels of care or interactions with healthcare services.ResultsThe impact of SPDM was detected within 1 week through population surveys, web search indicators and sentinel swabbing reported by onset date. There were detectable impacts on syndromic surveillance indicators for difficulty breathing, influenza-like illness and COVID-19 coding at 2, 7 and 12 days respectively, hospitalisations and critical care admissions (both 12 days), laboratory positivity (14 days), deaths (17 days) and nursing home outbreaks (4 weeks).ConclusionThe impact of SPDM on COVID-19 activity was detectable within 1 week through community surveillance indicators, highlighting their importance in early detection of changes in activity. Community swabbing surveillance may be increasingly important as a specific indicator, should circulation of seasonal respiratory viruses increase.


Subject(s)
COVID-19/prevention & control , Epidemiological Monitoring , Physical Distancing , COVID-19/epidemiology , Humans , United Kingdom/epidemiology
19.
Lancet ; 397(10283): 1459-1469, 2021 04 17.
Article in English | MEDLINE | ID: covidwho-1174548

ABSTRACT

BACKGROUND: Increased understanding of whether individuals who have recovered from COVID-19 are protected from future SARS-CoV-2 infection is an urgent requirement. We aimed to investigate whether antibodies against SARS-CoV-2 were associated with a decreased risk of symptomatic and asymptomatic reinfection. METHODS: A large, multicentre, prospective cohort study was done, with participants recruited from publicly funded hospitals in all regions of England. All health-care workers, support staff, and administrative staff working at hospitals who could remain engaged in follow-up for 12 months were eligible to join The SARS-CoV-2 Immunity and Reinfection Evaluation study. Participants were excluded if they had no PCR tests after enrolment, enrolled after Dec 31, 2020, or had insufficient PCR and antibody data for cohort assignment. Participants attended regular SARS-CoV-2 PCR and antibody testing (every 2-4 weeks) and completed questionnaires every 2 weeks on symptoms and exposures. At enrolment, participants were assigned to either the positive cohort (antibody positive, or previous positive PCR or antibody test) or negative cohort (antibody negative, no previous positive PCR or antibody test). The primary outcome was a reinfection in the positive cohort or a primary infection in the negative cohort, determined by PCR tests. Potential reinfections were clinically reviewed and classified according to case definitions (confirmed, probable, or possible) and symptom-status, depending on the hierarchy of evidence. Primary infections in the negative cohort were defined as a first positive PCR test and seroconversions were excluded when not associated with a positive PCR test. A proportional hazards frailty model using a Poisson distribution was used to estimate incidence rate ratios (IRR) to compare infection rates in the two cohorts. FINDINGS: From June 18, 2020, to Dec 31, 2020, 30 625 participants were enrolled into the study. 51 participants withdrew from the study, 4913 were excluded, and 25 661 participants (with linked data on antibody and PCR testing) were included in the analysis. Data were extracted from all sources on Feb 5, 2021, and include data up to and including Jan 11, 2021. 155 infections were detected in the baseline positive cohort of 8278 participants, collectively contributing 2 047 113 person-days of follow-up. This compares with 1704 new PCR positive infections in the negative cohort of 17 383 participants, contributing 2 971 436 person-days of follow-up. The incidence density was 7·6 reinfections per 100 000 person-days in the positive cohort, compared with 57·3 primary infections per 100 000 person-days in the negative cohort, between June, 2020, and January, 2021. The adjusted IRR was 0·159 for all reinfections (95% CI 0·13-0·19) compared with PCR-confirmed primary infections. The median interval between primary infection and reinfection was more than 200 days. INTERPRETATION: A previous history of SARS-CoV-2 infection was associated with an 84% lower risk of infection, with median protective effect observed 7 months following primary infection. This time period is the minimum probable effect because seroconversions were not included. This study shows that previous infection with SARS-CoV-2 induces effective immunity to future infections in most individuals. FUNDING: Department of Health and Social Care of the UK Government, Public Health England, The National Institute for Health Research, with contributions from the Scottish, Welsh and Northern Irish governments.


Subject(s)
Antibodies, Viral/blood , COVID-19/epidemiology , COVID-19/immunology , Health Personnel , Adult , Asymptomatic Infections , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing , England , Female , Follow-Up Studies , Humans , Male , Middle Aged , Pandemics , Prospective Studies , Reinfection , Risk Factors , SARS-CoV-2
20.
J Infect ; 82(4): 67-74, 2021 04.
Article in English | MEDLINE | ID: covidwho-1101374

ABSTRACT

INTRODUCTION: The reopening of schools during the COVID-19 pandemic has raised concern for the safety of staff and students, their families and the wider community. We monitored SARS-CoV-2 infection rates in school-aged children and compared them with adult infection rates before and after schools reopened in England. METHODS: Public Health England receives daily electronic reports of all SARS-CoV-2 tests nationally. SARS-CoV-2 infection rates by school year from July to December 2020 were analysed, including the effect of a national month-long lockdown whilst keeping schools open in November 2020 RESULTS: SARS-CoV-2 infections rates were low during early summer but started increasing in mid-August, initially in young adults followed by secondary and then primary school-aged children prior to schools reopening in September 2020. Cases in school-aged children lagged behind and followed adult trends after schools reopened, with a strong age gradient in weekly infection rates. There was a strong (P<0.001) correlation in regional infection rates between adults and secondary (R2=0.96-0.98), primary (R2=0.93-0.94) and preschool-aged (R2=0.62-0.85) children. The November lockdown was associated with declines in adult infection rates, followed a week later, by declines in student cases. From 23 November 2020, cases in adults and children increased rapidly following the emergence of a more transmissible novel variant of concern (VOC-202,012/01; B.1.1.7). CONCLUSIONS: In school-aged children, SARS-CoV-2 infections followed the same trajectory as adult cases and only declined after national lockdown was implemented whilst keeping schools open. Maintaining low community infection rates is critical for keeping schools open during the pandemic.


Subject(s)
COVID-19 , SARS-CoV-2 , Child , Child, Preschool , Communicable Disease Control , England/epidemiology , Humans , Pandemics , Prospective Studies , Schools
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