Benjamin J Cowling

Benjamin J Cowling
The University of Hong Kong | HKU · School of Public Health

BSc, PhD

About

885
Publications
161,784
Reads
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48,980
Citations
Additional affiliations
September 2004 - present
The University of Hong Kong
September 2003 - August 2004
Imperial College London
Education
September 2000 - August 2003
The University of Warwick
Field of study
  • Medical Statistics
September 1997 - July 2000
The University of Warwick
Field of study
  • MORSE (Mathematics, Operational Research, Statistics, Economics)

Publications

Publications (885)
Article
This cohort study investigates the association between relaxation of public health and social measures and daily cases of SARS-CoV-2 Omicron variant infection in South Korea.
Article
Background: Understanding the trend of global antifungal agent consumption could assist with identification of global healthcare policy inadequacies and promote accessibility and availability of antifungal agents. Methods: Using pharmaceutical sales data from the IQVIA-multinational integrated data analysis system database, we assessed use of sy...
Article
Background Influenza circulated at historically-low levels during 2020 and 2021 due to COVID-19 pandemic travel restrictions. In Australia, international arrivals to Australia were required to undertake 14 days hotel quarantine to limit new introduction of SARS-CoV-2 virus. Methods We used routine testing data for travellers arriving on repatriati...
Preprint
Background The generation time distribution, reflecting the time between successive infections in transmission chains, is one of the fundamental epidemiological parameters for describing COVID-19 transmission dynamics. However, because exact infection times are rarely known, it is often approximated by the serial interval distribution, reflecting t...
Article
Our analysis of data collected from multiple epidemics in Hong Kong indicated a shorter serial interval and generation time of infections with the SARS-CoV-2 Omicron variant. The age-specific case-fatality risk for Omicron BA.2.2 case-patients without complete primary vaccination was comparable to that of persons infected with ancestral strains in...
Article
To model estimated deaths averted by COVID-19 vaccines, we used state-of-the-art mathematical modeling, likelihood-based inference, and reported COVID-19 death and vaccination data. We estimated that >1.5 million deaths were averted in 12 countries. Our model can help assess effectiveness of the vaccination program, which is crucial for curbing the...
Preprint
Monkeypox, a fast-spreading viral zoonosis outside of Africa in May 2022, has scientists on alert. We estimated the reproduction number is estimated to be 1.29 (95% CrI: 1.26, 1.33) by aggregating all cases in 70 countries as of July 22, 2022.
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Background The protective effect of T cell-mediated immunity against influenza virus infections in natural settings remains unclear, especially in seasonal epidemics. Methods To explore the potential of such protection, we analyzed the blood samples collected longitudinally in a community-based study and covered the first wave of pandemic H1N1 (pH...
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We conducted a scoping review of the epidemiological literature from the past 50 years to document the contribution of influenza virus infection to extrapulmonary clinical outcomes. We identified 99 publications reporting 243 associations using many study designs, exposure and outcome definitions and methods. Laboratory confirmation of influenza wa...
Preprint
Introduction Third doses of COVID-19 vaccination provide an important boost to immunity, reducing the risk of symptomatic infection and the risk of severe disease. Third doses have been particularly important for improving protection against variants. However, waning of clinical protection particularly against Omicron has been noted after receipt o...
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China experienced a resurgence of seasonal influenza activity throughout 2021 despite intermittent control measures and prolonged international border closure. We show genomic evidence for multiple A(H3N2), A(H1N1), and B/Victoria transmission lineages circulating over three years, with the 2021 resurgence mainly driven by two B/Victoria clades. Ph...
Article
Superspreading, or overdispersion in transmission, is a feature of SARS‐CoV‐2 transmission which results in surging epidemics and large clusters of infection. The dispersion parameter is a statistical parameter used to characterize and quantify heterogeneity. In the context of measuring transmissibility, it is analogous to measures of superspreadin...
Article
Background Hong Kong maintained low circulation of SARS-CoV-2 until a major community epidemic of the omicron (B.1.1.529) sublineage BA.2 began in January 2022. Both mRNA (BNT162b2 [Fosun Pharma-BioNTech]) and inactivated CoronaVac (Sinovac, Beijing, China) vaccines are widely available; however, vaccination coverage has been low, particularly in o...
Article
Within‐host model specified by viral dynamic parameters is a mainstream tool to understand SARS‐CoV‐2 replication cycle in infected patients. The parameter uncertainty further affects the output of the model, such as the efficacy of potential antiviral drugs. However, gathering empirical data on these parameters is challenging. Here, we aim to cond...
Article
For better monitoring and controlling influenza, WHO has launched FluNet (recently integrated to FluMART) to provide a unified platform for participating countries to routinely collect influenza-related syndromic, epidemiological and virological data. However, the reported data were incomplete.We propose a novel surveillance system based on data fr...
Preprint
Background: On-arrival quarantine has been one of the primary measures used to prevent the introduction of COVID-19 into Hong Kong since the start of the pandemic. Most on-arrival quarantines have been done in hotels, with the duration of quarantine and testing frequency during quarantine varying throughout the pandemic for various reasons. However...
Article
Omicron, a fast-spreading SARS-CoV-2 variant of concern reported to the World Health Organization on November 24, 2021, has raised international alarm. We estimated there is at least 50% chance that Omicron had been introduced by travellers from South Africa into 11 of the 14 countries studied by November 28, 2021.
Article
Background: Limited data exist on antibody responses to mixed vaccination strategies involving inactivated COVID-19 vaccines, particularly in the context of emerging variants. Methods: We conducted an open label trial of a third vaccine dose of an mRNA vaccine (BNT162b2, Fosun Pharma/BioNTech) in adults aged ≥30 years who had previously received...
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Background COVID-19 vaccine hesitancy can lead to reduced vaccine uptake and hinder the safe relaxation of other public health measures. This study aims to explore the factors associated with vaccine hesitancy and uptake among adults before and after the implementation of the COVID-19 vaccination program in Hong Kong. Methods Cross-sectional telep...
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LINKED CONTENT This article is linked to Wong et al papers. To view these articles, visit https://doi.org/10.1111/apt.16894 and https://doi.org/10.1111/apt.16921
Article
We studied 2780 adults in Hong Kong who received CoronaVac inactivated virus vaccine (Sinovac) and BNT162b2 mRNA vaccine (“Comirnaty”, BioNTech/Fosun Pharma). We compared rates of antibody waning over time using an enzyme-linked immunosorbent assay for spike receptor binding domain and a surrogate virus neutralization test. We found stronger and mo...
Preprint
Background Evidence evaluating real-world effectiveness of oral antivirals against Omicron variants is lacking. Methods An unselected, territory-wide cohort of all initially non-hospitalized patients with an officially registered diagnosis of SARS-CoV-2 infection between 26th February and 3rd May 2022 during the Omicron BA.2.2 wave in Hong Kong, w...
Preprint
Background Real-world evidence on the effectiveness of oral antivirals in mild-to-moderate COVID-19 patients is urgently needed. This retrospective cohort study aims to evaluate the clinical and virologic outcomes associated with molnupiravir and nirmatrelvir/ritonavir use in COVID-19 patients during a pandemic wave dominated by the Omicron BA.2 va...
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Importance: COVID-19 has required universities to rapidly develop vaccination policies for students and staff, yet little is known about the preferences of these individuals toward vaccination. Objective: To quantify student and staff preferences for COVID-19 vaccination at a university in Hong Kong. Design, setting, and participants: A cross-...
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Given global Coronavirus Disease 2019 (COVID-19) vaccine shortages and inequity of vaccine distributions, fractionation of vaccine doses might be an effective strategy for reducing public health and economic burden, notwithstanding the emergence of new variants of concern. In this study, we developed a multi-scale model incorporating population-lev...
Article
Zoonotic influenza infections continue to threaten human health. Ongoing surveillance and risk assessment of animal viruses are needed for pandemic preparedness, and population immunity is an important component of risk assessment. We determined age-stratified hemagglutinin inhibition seroprevalence against 5 swine influenza viruses circulating in...
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Objectives: This retrospective cohort study aims to explore head-to-head clinical outcomes and complications associated with tocilizumab or baricitinib initiation among hospitalized COVID-19 patients receiving dexamethasone. Methods: Among 10,445 COVID-19 patients hospitalized between January 21st 2020 and January 31st 2021 in Hong Kong, patients w...
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Influenza virus infections can lead to a number of secondary complications, including sepsis. We applied linear regression models to mortality and hospital admission data coded for septicaemia from 1998 to 2019 in Hong Kong, and estimated that septicaemia was associated with an annual average excess mortality rate of 0.23 (95% CI 0.04–0.40) per 100...
Article
https://academic.oup.com/jtm/advance-article/doi/10.1093/jtm/taac052/6571349?searchresult=1
Article
Objectives: There was initially insufficient understanding regarding suitable pharmacological treatment for pediatric Coronavirus Disease 2019 (COVID-19) patients. Lopinavir-ritonavir (LPV/r) was originally used for the treatment of Human Immunodeficiency Virus-1 (HIV-1) infection. It was also used in patients with severe acute respiratory syndrom...
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COVID-19 remains a persistent threat, especially with the predominant Omicron variant emerging in early 2022, presenting with high transmissibility, immune escape, and waning. There is a need to rapidly ramp up global vaccine coverage while enhancing public health and social measures. Timely and reliable estimation of the reproduction number throug...
Article
Targeting surveillance resources towards individuals at high risk of early infection can accelerate the detection of emerging outbreaks. However, it is unclear which individuals are at high risk without detailed data on interpersonal and physical contacts. We propose a data-driven COVID-19 surveillance strategy using Electronic Health Record (EHR)...
Preprint
Hong Kong reported 12,631 confirmed COVID-19 cases and 213 deaths in the first two years of the pandemic but experienced a major wave predominantly of Omicron BA.2.2 in early 2022 with over 1.1 million reported SARS-CoV-2 infections and more than 7900 deaths. Our data indicated a shorter incubation period, serial interval, and generation time of in...
Article
We explored the potential for a biphasic pattern in waning of antibody titers after influenza vaccination. We collected blood samples in a randomized controlled trial of influenza vaccination in children, and tested them with hemagglutination inhibition (HAI) assays for influenza A(H3N2) and influenza B/Victoria lineage. Using piecewise log-linear...
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Background As SARS-CoV-2 vaccines are administered worldwide, the COVID-19 pandemic continues to exact significant human and economic costs. Mass testing of unvaccinated individuals followed by isolation of positive cases can substantially mitigate risks and be tailored to local epidemiological conditions to ensure cost effectiveness. Methods Usin...
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Background Several countries have implemented control measures to limit SARS-CoV-2 spread, including digital contact tracing, digital monitoring of quarantined individuals and testing of travelers. These raise ethical issues around privacy, personal freedoms and equity. However, little is known regarding public acceptability of these measures. Met...
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Annual epidemics of seasonal influenza cause hundreds of thousands of deaths, high levels of morbidity, and substantial economic loss. Yet, global influenza circulation has been heavily suppressed by public health measures and travel restrictions since the onset of the COVID-19 pandemic. Notably, the influenza B/Yamagata lineage has not been conclu...
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For >70 years, a 4-fold or greater rise in antibody titer has been used to confirm influenza virus infections in paired sera, despite recognition that this heuristic can lack sensitivity. Here we analyze with a novel Bayesian model a large cohort of 2353 individuals followed for up to 5 years in Hong Kong to characterize influenza antibody dynamics...
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Background The Delta variant of SARS-CoV-2 had become predominant globally by November 2021. Aim We evaluated transmission dynamics and epidemiological characteristics of the Delta variant in an outbreak in southern China. Methods Data on confirmed COVID-19 cases and their close contacts were retrospectively collected from the outbreak that occur...
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Given the worldwide pandemic of the novel coronavirus disease 2019 (COVID-19) and its continuing threat brought by the emergence of virus variants, there are great demands for accurate surveillance and monitoring of outbreaks. A valuable metric for assessing the current risk posed by an outbreak is the time-varying reproduction number (Rt). Several...
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Many locations around the world have used real-time estimates of the time-varying effective reproductive number (Rt) of COVID-19 to provide evidence of transmission intensity to inform control strategies. Estimates of Rt are typically based on statistical models applied to case counts and typically suffer lags of more than a week because of the lat...
Article
Controlling transmission in restaurants is an important component of public health and social measures for coronavirus disease. We examined the effects of restaurant measures in Hong Kong. Our findings indicate that shortening operating hours did not have an effect on time-varying effective reproduction number when capacity was already reduced.
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AimThis study was conducted in order to evaluate the association between metformin use and clinical outcomes in type 2 diabetes mellitus (T2DM) patients hospitalized with coronavirus disease 2019 (COVID-19).Methods Patients with T2DM with confirmed diagnosis of COVID-19 and admitted between January 21, 2020, and January 31, 2021 in Hong Kong were i...
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Background Understanding the relative transmissibility of SARS-CoV-2 virus across different contact settings and the possibility of superspreading events is important for prioritizing disease control. Such assessment requires proper consideration of individual level exposure history, which is made possible by contact tracing. Methods The case-asce...
Article
The COVID-19 pandemic continues to pose substantial risks to public health, worsened by the emergence of SARS-CoV-2 variants which may have a higher transmissibility and reduce vaccine effectiveness. We conducted a systematic review and meta-analysis on reproduction numbers of SARS-CoV-2 variants and provided pooled estimates for each variant.
Preprint
We studied 2864 adults in Hong Kong who received CoronaVac inactivated virus vaccine (Sinovac) and BNT162b2 mRNA vaccine (Comirnaty, BioNTech/Fosun Pharma). We found stronger and more durable antibody responses to two doses of the mRNA vaccine, and slightly stronger initial antibody responses to each vaccine in younger adults and women.
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Hong Kong employed a strategy of intermittent public health and social measures alongside increasingly stringent travel regulations to eliminate domestic SARS-CoV-2 transmission. By analyzing 1899 genome sequences (>18% of confirmed cases) from 23-January-2020 to 26-January-2021, we reveal the effects of fluctuating control measures on the evolutio...
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We present an R package developed to quantify coronavirus disease 2019 (COVID-19) importation risk. Quantifying and visualizing the importation risk of COVID-19 from inbound travelers is urgent and imperative to trigger public health responses, especially in the early stages of the COVID-19 pandemic and emergence of new SARS-CoV-2 variants. We prov...
Article
This study aims to provide evidence on how the COVID-19 pandemic has impacted chronic disease care in diverse settings across Asia. Cross-sectional surveys were conducted to assess the health, social, and economic consequences of the pandemic in India, China, Hong Kong, Korea, and Vietnam using standardized questionnaires. Overall, 5672 participant...
Preprint
Limited data exist on antibody responses to mixed vaccination strategies involving inactivated COVID-19 vaccines, particularly in the context of emerging variants. We conducted an open label trial and administered a third vaccine dose of an mRNA vaccine (BNT162b2, BioNTech/Fosun Pharma) in adults aged ≥30 years who had previously received two doses...
Article
Vaccine hesitancy can be heightened due to increasing negative reports about vaccines. Emphasizing the social benefits of vaccination may shift individual attention from individual to social benefit of vaccination and hence promote prosocial vaccination. In six rounds of a population-based survey conducted over one major community epidemic of coron...
Article
To determine the effects of nonpharmaceutical interventions (NPIs) for coronavirus disease on pediatric hospitalizations for infection with respiratory viruses other than severe acute respiratory syndrome coronavirus 2, we analyzed hospital data for 2017-2021. Compared with 2017-2019, age-specific hospitalization rates associated with respiratory v...
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We estimated mean serial interval and superspreading potential for the Delta variant of severe acute respiratory syndrome coronavirus 2 in South Korea. Intervals were similar for the first (3.7 days) and second (3.5 days) study periods. Risk for superspreading events was also similar; 23% and 25% of cases, respectively, seeded 80% of transmissions.
Preprint
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Superspreading in transmission is a feature of SARS-CoV-2 transmission. We conducted a systematic review and meta-analysis on globally reported dispersion parameters of SARS-CoV-2. The pooled estimate was 0.55 (95% CI: 0.30, 0.79). The study location and method were found to be important drivers for its diversity.
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Omicron, a fast-spreading SARS-CoV-2 variant of concern reported to the World Health Organization on November 24, 2021, has raised international alarm. We estimated there is at least 50% chance that Omicron had been introduced by travelers from South Africa into all of the 30 countries studied by November 27, 2021.
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Full-text available
We report detection of severe acute respiratory syndrome coronavirus 2 Omicron variant (B.1.1.529) in an asymptomatic, fully vaccinated traveler in a quarantine hotel in Hong Kong, China. The Omicron variant was also detected in a fully vaccinated traveler staying in a room across the corridor from the index patient, suggesting transmission despite...
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Background and objectives Type 2 diabetes mellitus (T2DM) patients with Coronavirus Disease 2019 (COVID-19) have poorer prognosis. Inconclusive evidence suggested dipeptidyl peptidase-4 inhibitors (DPP4i) might reduce inflammation and prevent Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) entry hence further evaluation on DPP4i is nee...
Article
The number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to increase worldwide, but despite extensive research, there remains significant uncertainty about the predominant routes of SARS-CoV-2 transmission. We conducted a mechanistic modeling and calculated the exposure dose and infection risk of eac...
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Objectives This study aims to explore the attenuated impact of reported avoidance behaviours adherence on the transmission of COVID-19 through cross-sectional surveys in Hong Kong, in order to make up for the lack of research on avoidance behaviours fatigue. Design 40 cross-sectional telephone surveys. Setting All districts in Hong Kong. Partici...
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Monitoring community psychological and behavioural responses to coronavirus disease 2019 (COVID-19) is important for informing policy making and risk communication to sustain public compliance with challenging precautionary behaviours and mitigating the psychological impacts. Monthly telephone-based cross-sectional surveys in January–April 2020 and...
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The methods to ascertain cases of an emerging infectious disease are typically biased toward cases with more severe disease, which can bias the average infection-severity profile. Here, we conducted a systematic review to extract information on disease severity among index cases and secondary cases identified by contact tracing of index cases for C...