Haowei Wang

Bio: Haowei Wang is an academic researcher from Imperial College London. The author has contributed to research in topics: Population & Mainland China. The author has an hindex of 7, co-authored 13 publications receiving 123 citations.

Resurgence of SARS-CoV-2: Detection by community viral surveillance.

Abstract: Surveillance of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has mainly relied on case reporting, which is biased by health service performance, test availability, and test-seeking behaviors. We report a community-wide national representative surveillance program in England based on self-administered swab results from ~594,000 individuals tested for SARS-CoV-2, regardless of symptoms, between May and the beginning of September 2020. The epidemic declined between May and July 2020 but then increased gradually from mid-August, accelerating into early September 2020 at the start of the second wave. When compared with cases detected through routine surveillance, we report here a longer period of decline and a younger age distribution. Representative community sampling for SARS-CoV-2 can substantially improve situational awareness and feed into the public health response even at low prevalence.

Resurgence of SARS-CoV-2 in England: detection by community antigen surveillance

Abstract: Summary Background Based on cases and deaths, transmission of SARS-CoV-2 in England peaked in late March and early April 2020 and then declined until the end of June. Since the start of July, cases have increased, while deaths have continued to decrease. Methods We report results from 594,000 swabs tested for SARS-CoV-2 virus obtained from a representative sample of people in England over four rounds collected regardless of symptoms, starting in May 2020 and finishing at the beginning of September 2020. Swabs for the most recent two rounds were taken between 24th July and 11th August and for round 4 between 22nd August and 7th September. We estimate weighted overall prevalence, doubling times between and within rounds and associated reproduction numbers. We obtained unweighted prevalence estimates by sub-groups: age, sex, region, ethnicity, key worker status, household size, for which we also estimated odds of infection. We identified clusters of swab-positive participants who were closer, on average, to other swab-positive participants than would be expected. Findings Over all four rounds of the study, we found that 72% (67%, 76%) of swab-positive individuals were asymptomatic at the time of swab and in the week prior. The epidemic declined between rounds 1 and 2, and rounds 2 and 3. However, the epidemic was increasing between rounds 3 and 4, with a doubling time of 17 (13, 23) days corresponding to an R value of 1.3 (1.2, 1.4). When analysing round 3 alone, we found that the epidemic had started to grow again with 93% probability. Using only the most recent round 4 data, we estimated a doubling time of 7.7 (5.5, 12.7) days, corresponding to an R value of 1.7 (1.4, 2.0). Cycle threshold values were lower (viral loads were higher) for rounds 1 and 4 than they were for rounds 2 and 3. In round 4, we observed the highest prevalence in participants aged 18 to 24 years at 0.25% (0.16%, 0.41%), increasing from 0.08% (0.04%, 0.18%) in round 3. We observed the lowest prevalence in those aged 65 and older at 0.04% (0.02%, 0.06%) which was stable compared with round 3. Participants of Asian ethnicity had elevated odds of infection. We identified clusters in and around London, transient clusters in the Midlands, and an expanding area of clustering in the North West and more recently in Yorkshire and the Humber. Interpretation Although low levels of transmission persisted in England through to mid-summer 2020, the prevalence of SARS-CoV-2 is now increasing. We found evidence of accelerating transmission at the end of August and beginning of September. Representative community antigen sampling can increase situational awareness and help improve public health decision making even at low prevalence.

REACT-1 round 6 updated report: high prevalence of SARS-CoV-2 swab positivity with reduced rate of growth in England at the start of November 2020

Abstract: Background England is now in the midst of its second wave of the COVID-19 pandemic. Multiple regions of the country are at high infection prevalence and all areas experienced rapid recent growth of the epidemic during October 2020. Methods REACT-1 is a series of community surveys of SARS-CoV-2 RT-PCR swab-positivity in England designed to monitor the spread of the epidemic and thus increase situational awareness. Round 6 of REACT-1 commenced swab-collection on 16th October. A prior interim report included data from 16th to 25th October for 85,971 participants. Here, we report data for the entire round on 160,175 participants with swab results obtained up to 2nd November 2020. Results Overall weighted prevalence of infection in the community in England was 1.3% or 130 people per 10,000 infected, up from 60 people per 10,000 in the round 5 report (18th September to 5th October 2020), doubling every 24 days on average since the prior round. The corresponding R number was estimated to be 1.2. Prevalence of infection was highest in North West (2.4%, up from 1.2%), followed by Yorkshire and The Humber (2.3% up from 0.84%), West Midlands (1.6% up from 0.60%), North East (1.5% up from 1.1%), East Midlands (1.3% up from 0.56%), London (0.97%, up from 0.54%), South West (0.80% up from 0.33%), South East (0.69% up from 0.29%), and East of England (0.69% up from 0.30%). Rapid growth in the South observed in the first half of round 6 was no longer apparent in the second half of round 6. We also observed a decline in prevalence in Yorkshire and The Humber during this period. Comparing the first and second halves of round 6, there was a suggestion of decline in weighted prevalence in participants aged 5 to 12 years and in those aged 25 to 44 years. While prevalence remained high, in the second half of round 6 there was suggestion of a slight fall then rise that was seen nationally and also separately in both the North and the South. Conclusion The impact of the second national lockdown in England is not yet known. We provide here a detailed description of swab-positivity patterns at national, regional and local scales for the period immediately preceding lockdown, against which future trends in prevalence can be evaluated.

REACT-1 round 8 final report: high average prevalence with regional heterogeneity of trends in SARS-CoV-2 infection in the community in England during January 2021

Abstract: In early January 2021, England entered its third national lockdown of the COVID-19 pandemic to reduce numbers of deaths and pressure on healthcare services, while rapidly rolling out vaccination to healthcare workers and those most at risk of severe disease and death. REACT-1 is a survey of SARS-CoV-2 prevalence in the community in England, based on repeated cross-sectional samples of the population. Between 6th and 22nd January 2021, out of 167,642 results, 2,282 were positive giving a weighted national prevalence of infection of 1.57% (95% CI, 1.49%, 1.66%). The R number nationally over this period was estimated at 0.98 (0.92, 1.04). Prevalence remained high throughout, but with suggestion of a decline at the end of the study period. The average national trend masked regional heterogeneity, with robustly decreasing prevalence in one region (South West) and increasing prevalence in another (East Midlands). Overall prevalence at regional level was highest in London at 2.83% (2.53%, 3.16%). Although prevalence nationally was highest in the low-risk 18 to 24 year old group at 2.44% (1.96%, 3.03%), it was also high in those over 65 years who are most at risk, at 0.93% (0.82%, 1.05%). Large household size, living in a deprived neighbourhood, and Black and Asian ethnicity were all associated with higher levels of infections compared to smaller households, less deprived neighbourhoods and other ethnicities. Healthcare and care home workers, and other key workers, were more likely to test positive compared to other workers. If sustained lower prevalence is not achieved rapidly in England, pressure on healthcare services and numbers of COVID-19 deaths will remain unacceptably high.

Assessing transmissibility of SARS-CoV-2 lineage B.1.1.7 in England.

Abstract: The SARS-CoV-2 lineage B.1.1.7, designated variant of concern (VOC) 202012/01 by Public Health England1, was first identified in the UK in late summer to early autumn 20202. Whole-genome SARS-CoV-2 sequence data collected from community-based diagnostic testing for COVID-19 show an extremely rapid expansion of the B.1.1.7 lineage during autumn 2020, suggesting that it has a selective advantage. Here we show that changes in VOC frequency inferred from genetic data correspond closely to changes inferred by S gene target failures (SGTF) in community-based diagnostic PCR testing. Analysis of trends in SGTF and non-SGTF case numbers in local areas across England shows that B.1.1.7 has higher transmissibility than non-VOC lineages, even if it has a different latent period or generation time. The SGTF data indicate a transient shift in the age composition of reported cases, with cases of B.1.1.7 including a larger share of under 20-year-olds than non-VOC cases. We estimated time-varying reproduction numbers for B.1.1.7 and co-circulating lineages using SGTF and genomic data. The best-supported models did not indicate a substantial difference in VOC transmissibility among different age groups, but all analyses agreed that B.1.1.7 has a substantial transmission advantage over other lineages, with a 50% to 100% higher reproduction number.

The State Council of the People's Republic of China Order No. 321

Abstract: (2011). The State Council of the People's Republic of China Order No. 321. Chinese Law & Government: Vol. 44, No. 4, pp. 42-48.

Persistent COVID-19 symptoms in a community study of 606,434 people in England

Abstract: Abstract Long COVID remains a broadly defined syndrome, with estimates of prevalence and duration varying widely. We use data from rounds 3–5 of the REACT-2 study ( n = 508,707; September 2020 – February 2021), a representative community survey of adults in England, and replication data from round 6 ( n = 97,717; May 2021) to estimate the prevalence and identify predictors of persistent symptoms lasting 12 weeks or more; and unsupervised learning to cluster individuals by reported symptoms. At 12 weeks in rounds 3–5, 37.7% experienced at least one symptom, falling to 21.6% in round 6. Female sex, increasing age, obesity, smoking, vaping, hospitalisation with COVID-19, deprivation, and being a healthcare worker are associated with higher probability of persistent symptoms in rounds 3–5, and Asian ethnicity with lower probability. Clustering analysis identifies a subset of participants with predominantly respiratory symptoms. Managing the long-term sequelae of COVID-19 will remain a major challenge for affected individuals and their families and for health services.

Adherence to the test, trace, and isolate system in the UK: results from 37 nationally representative surveys.

Abstract: Objective To investigate rates of adherence to the UK’s test, trace, and isolate system over the initial 11 months of the covid-19 pandemic. Design Series of cross sectional online surveys. Setting 37 nationally representative surveys in the UK, 2 March 2020 to 27 January 2021. Participants 74 697 responses from 53 880 people living in the UK, aged 16 years or older (37 survey waves, about 2000 participants in each wave). Main outcome measures Identification of the main symptoms of covid-19 (cough, high temperature or fever, and loss of sense of smell or taste), self-reported adherence to self-isolation if symptoms were present and intention to self-isolate if symptoms were to develop, requesting a test for covid-19 if symptoms were present and intention to request a test if symptoms were to develop, and intention to share details of close contacts. Results Only 51.5% of participants (95% confidence interval 51.0% to 51.9%, n=26 030/50 570) identified the main symptoms of covid-19; the corresponding values in the most recent wave of data collection (25-27 January 2021) were 50.8% (48.6% to 53.0%, n=1019/2007). Across all waves, duration adjusted adherence to full self-isolation was 42.5% (95% confidence interval 39.7% to 45.2%, n=515/1213); in the most recent wave of data collection (25-27 January 2021), it was 51.8% (40.8% to 62.8%, n=43/83). Across all waves, requesting a test for covid-19 was 18.0% (95% confidence interval 16.6% to 19.3%, n=552/3068), increasing to 22.2% (14.6% to 29.9%, n=26/117) from 25 to 27 January. Across all waves, intention to share details of close contacts was 79.1% (95% confidence interval 78.8% to 79.5%, n=36 145/45 680), increasing to 81.9% (80.1% to 83.6%, n=1547/1890) from 25 to 27 January. Non-adherence was associated with being male, younger age, having a dependent child in the household, lower socioeconomic grade, greater financial hardship during the pandemic, and working in a key sector. Conclusions Levels of adherence to test, trace, and isolate are low, although some improvement has occurred over time. Practical support and financial reimbursement are likely to improve adherence. Targeting messaging and policies to men, younger age groups, and key workers might also be necessary.

Spatiotemporal invasion dynamics of SARS-CoV-2 lineage B.1.1.7 emergence.

Abstract: Understanding the causes and consequences of the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern is crucial to pandemic control yet difficult to achieve because they arise in the context of variable human behavior and immunity. We investigated the spatial invasion dynamics of lineage B.1.1.7 by jointly analyzing UK human mobility, virus genomes, and community-based polymerase chain reaction data. We identified a multistage spatial invasion process in which early B.1.1.7 growth rates were associated with mobility and asymmetric lineage export from a dominant source location, enhancing the effects of B.1.1.7's increased intrinsic transmissibility. We further explored how B.1.1.7 spread was shaped by nonpharmaceutical interventions and spatial variation in previous attack rates. Our findings show that careful accounting of the behavioral and epidemiological context within which variants of concern emerge is necessary to interpret correctly their observed relative growth rates.