Prevalence of persistent symptoms in children during the COVID-19 pandemic: evidence from a household cohort study in England and Wales

Using data from 4678 children participating in VirusWatch, a household cohort study, we estimated the prevalence of persistent symptoms lasting [≥]4 weeks as 1.7%, and 4.6% in children with a history of SARS-CoV-2 infection. Persistent symptom prevalence was higher in girls, teenagers and children with long-term conditions.

Occupation, Work-Related Contact, and SARS-CoV-2 Anti-Nucleocapsid Serological Status: Findings from the Virus Watch prospective cohort study

BackgroundWorkers differ in their risk of acquiring SARS-CoV-2 infection according to their occupation; however, few studies have been able to control for multiple confounders or investigate the work-related factors that drive differences in occupational risk. Using data from the Virus Watch community cohort study in England and Wales, we set out to estimate the total effect of occupation on SARS-CoV-2 serological status, whether this is mediated by frequency of close contact within the workplace, and how exposure to poorly ventilated workplaces varied across occupations. MethodsWe used data from a sub-cohort (n =3761) of adults ([≥]18) tested for SARS-CoV-2 anti-nucleocapsid antibodies between 01 February-28 April 2021 and responded to a questionnaire about work during the pandemic. Anti-nucleocapsid antibodies were used as a proxy of prior natural infection with COVID-19. We used logistic decomposition to estimate the total and direct effect of occupation and indirect effect of workplace contact frequency on odds of seropositivity, adjusting for age, sex, household income and region. We investigated the relationship between occupation and exposure to poorly-ventilated workplace environments using ordinal logistic regression. ResultsSeropositivity was 16.0% (113/707) amongst workers with daily close contact, compared to 12.9% (120/933) for those with intermediate-frequency contact and 9.6% (203/2121) for those with no work-related close contact. Healthcare (OR= 2.14, 95% CI 1.47,3.12), indoor trade, process and plant (2.09, 1.31,3.33), leisure and personal service (1.96, 1.004,3.84), and transport and mobile machine (2.17, 1.12,4.18) workers had elevated total odds of SARS-CoV-2 seropositivity compared to other professional and associate occupations. Frequency of workplace contact accounted for a variable part of the increased odds in different occupational groups (OR range 1.04 [1.0004,1.07] - 1.22 [1.07, 1.38]). Healthcare workers and indoor trades and process plant workers continued to have raised odds of infection after accounting for work-related contact, and also had had greater odds of frequent exposure to poorly-ventilated workplaces (respectively 2.15 [1.66, 2.79] and (1.51, [1.12, 2.04]). DiscussionMarked variations in occupational odds of seropositivity remain after accounting for age, sex, region, and household income. Close contact in the workplace appears to contribute substantially to this variation. Reducing frequency of workplace contact is a critical part of COVID-19 control measures.

Symptom profiles and accuracy of clinical definitions for COVID-19 in the community. Results of the Virus Watch community cohort.

BackgroundUnderstanding the symptomatology and accuracy of clinical case definitions for COVID-19 in the community is important for the initiation of Test, Trace and Isolate (TTI) and may, in future, be important for early prescription of antivirals. MethodsVirus Watch is a large community cohort with prospective daily recording of a wide range of symptoms and self-reporting of swab results (mainly undertaken through the UK TTI system). We compared frequency, severity, timing, and duration of symptoms in test positive and test negative cases. We compared the test performance of the current UK case definition used by TTI (any one of: new continuous cough, high temperature, or loss of or altered sense of smell or taste) with a wider definition that also included muscle aches, chills, headache, or loss of appetite. FindingsWe included results from 8213 swabbed illnesses, 944 of which tested positive for SARS-CoV-2. All symptoms were more common in test positive than test negative illnesses and symptoms were also more severe and of longer duration. Common symptoms such as cough, headache, fatigue, muscle aches, and loss of appetite occurred early in the course of illness but were also very common in test-negative illnesses. In contrast, high temperature and loss of or altered sense of smell or taste were less frequently identified in swab positive illnesses but were markedly more common than in swab negative illnesses. The current UK definition had a sensitivity and specificity of 81% and 47% respectively for symptomatic COVID-19 compared to 93% and 26% for the broader definition. On average, cases met the broader case definition 0.3 days earlier than the current definition. 1.7-fold more illnesses met the broader definition than the current case definition. InterpretationCOVID-19 is difficult to distinguish from other respiratory infections and common ailments on the basis of symptoms. Broadening the list of symptoms used to encourage engagement with TTI could moderately increase the number of infections identified and shorten delays to isolation, but with a large increase in the number of tests needed and the number of unwell individuals and contacts who are advised to self-isolate whilst awaiting results, and subsequently test negative for SARS-CoV-2.

Serial interval of COVID-19 and the effect of Variant B.1.1.7: analyses from a prospective community cohort study (Virus Watch).

IntroductionIncreased transmissibility of B.1.17 variant of concern (VOC) in the UK may explain its rapid emergence and global spread. We analysed data from putative household infector - infectee pairs in the Virus Watch Community cohort study to assess the serial interval of COVID-19 and whether this was affected by emergence of the B.1.17 variant. MethodsThe Virus Watch study is an online, prospective, community cohort study following up entire households in England and Wales during the COVID-19 pandemic. Putative household infector-infectee pairs were identified where more than one person in the household had a positive swab matched to an illness episode. Data on whether individual infections were caused by the B.1.1.7 variant were not available. We therefore developed a classification system based on the percentage of cases estimated to be due to B.1.17 in national surveillance data for different English regions and study weeks. ResultsOut of 24,887 illnesses reported, 915 tested positive for SARS-CoV-2 and 186 likely infector-infectee pairs in 186 households amongst 372 individuals were identified. The mean COVID-19 serial interval was 3.18 (95%CI: 2.55 - 3.81) days. There was no significant difference (p=0.267) between the mean serial interval for Variants of Concern (VOC) hotspots (mean = 3.64 days, (95%CI: 2.55 - 4.73)) days and non-VOC hotspots, (mean = 2.72 days, (95%CI: 1.48 - 3.96)). ConclusionsOur estimates of the average serial interval of COVID-19 are broadly similar to estimates from previous studies and we find no evidence that B.1.1.7 is associated with a change in serial intervals. Alternative explanations such as increased viral load, longer period of viral shedding or improved receptor binding may instead explain the increased transmissibility and rapid spread and should undergo further investigation.

Deprivation and Exposure to Public Activities during the COVID-19 Pandemic in England and Wales

BackgroundDifferential exposure to public activities and non-household contacts may contribute to stark deprivation-related inequalities in SARS-CoV-2 infection and outcomes, but has not been directly investigated. We set out to investigate whether participants in Virus Watch - a large community cohort study based in England and Wales - reported different levels of exposure to public activities and non-household contacts during the Autumn-Winter phase of the COVID-19 pandemic according to postcode-level socioeconomic deprivation. MethodsParticipants (n=20120-25228 across surveys) reported their daily activities during three weekly periods in late November 2020, late December 2020, and mid-February 2021. Deprivation was quantified based on participants postcode of residence using English or Welsh Indices of Multiple Deprivation quintiles. We used Poisson mixed effect models with robust standard errors to estimate the relationship between deprivation and risk of exposure to public activities during each survey period. ResultsRelative to participants in the least deprived areas, participants in the most deprived areas persistently exhibited elevated risk of exposure to vehicle sharing (aRR range across time points 1.73-8.52), public transport (aRR 3.13-5.73), work or education outside of the household (aRR 1.09-1.21), essential shops (aRR 1.09-1.13) and non-household contacts (aRR 1.15-1.19) across multiple survey periods. ConclusionDifferential exposure to essential public activities in deprived communities is likely to contribute to inequalities in infection risk and outcomes during the COVID-19 pandemic. Public health interventions to reduce exposure during essential activities and financial and practical support to enable low-paid workers to stay at home during periods of intense transmission may reduce COVID-related inequalities.

Trends, patterns and psychological influences on COVID-19 vaccination intention: findings from a large prospective community cohort study in England and Wales (Virus Watch)

ObjectivesTo assess trends in intention to accept a COVID-19 vaccine between 1 December 2020 and 25 February 2021, explore associations between socio-demographic factors and vaccination intention and investigate how COVID-19 vaccine- and illness-related attitudes, beliefs and emotions influence vaccination intention. DesignProspective household community cohort study of COVID-19 infection (Virus Watch). SettinOnline survey of Virus Watch study participants in the community across England and Wales. ParticipantsIndividuals could enrol in Virus Watch if all household members agreed to participate and at least one household member had access to the internet, an email address, and could read English. All Virus Watch participants aged 16 years and over who responded to questions relating to COVID-19 vaccine intention in questionnaires between December 2020 and February 2021 were included in this analysis. Main outcome measuresVaccination intention was measured by individual participant responses to Would you accept a COVID-19 vaccine if offered?, collected between 1-14 December 2020 and 17-25 February 2021. Possible responses were Yes, No and Unsure (December 2020 &February 2021) and Already had a COVID-19 vaccine (February 2021 only). Responses to a 13-item questionnaire collected between 4-11 January 2021 were analysed using factor analysis to investigate psychological influences (attitudes, beliefs and emotions) on vaccination intention. ResultsSurvey response rate was 56% (20,792/36,998) in December 2020 and 52% (20,284/38,727) in February 2021, with 14,713 adults reporting across both time points. Of participants reporting across both timepoints, 13,281 (90%) answered Yes and 1,432 (10%) responded No or Unsure in December 2020. Of those answering No or Unsure in December 2020, 1,233 (86%) went on to answer Yes or Already had a COVID-19 vaccine in February 2021. The magnitude of this shift was consistent across all ethnic groups measured and all levels of social deprivation. Age was most strongly associated with vaccination intention, with 16-24-year-olds more likely to respond "No" or "Unsure" than those aged 75+ in December 2020 (RR: 4.32, 95% CI: 2.40-7.78 &2.93 95% CI: 2.19-3.92, respectively) and February 2021 (RR: 5.30 95% CI: 1.39-20.20 &20.21 95%CI: 7.19-56.78). The association between ethnicity and vaccination intention has weakened, but not disappeared, over time. Both vaccine- and illness-related psychological factors were shown to influence vaccination intention. ConclusionsOver four in five adults (86%) who were reluctant or intending to refuse a COVID-19 vaccine in December 2020 had changed their mind in February 2021 and planned on accepting, or had already accepted, a vaccine.