ABSTRACT
Background: Vaccine hesitancy has seriously compromised the COVID-19 vaccine roll-out across the Western Pacific; nevertheless, evidence-based recommendations that account for the heterogeneity of vaccine-hesitant populations in this region remain lacking. To help design customized vaccine communication strategies, we sought to investigate the profile of the vaccine-hesitant populations in Cambodia, Japan, Lao PDR, Malaysia, Mongolia, Papua New Guinea, Philippines, Republic of Korea, and Viet Nam. Methods: Using 16,408 survey responses from an international survey distributed in 2021 and 2022, we identified hidden subgroups by conducting latent class analysis (LCA) and examined their vaccine acceptance and booster uptake by using Ordinary Least Square (OLS) regressions. Findings: Our LCA approach identified six classes: college students, distrusters of health care providers (HCPs), stay-at-home mothers, the elderly, compliant pragmatists, and general working population. Booster uptake were significantly low in two groups: college students [13 percentage points; 95% CI -0.21 to -0.05] and HCP distrusters [8 percentage points; 95% CI -0.15 to -0.01]; these groups’ acceptance were also similarly low. Stay-at-home mothers’ acceptance and uptake were comparable, but this group took a large portion of vaccine-hesitant people in the Philippines. The profiles of the vaccine-hesitant populations in each country were compared and categorized into four groups, depending on the composition of classes that account for the unvaccination population. Interpretation: The results of this study suggest that drivers of vaccine hesitancy may vary by country and indicate that each country needs a customized strategy that reflects the profile of its vaccine-hesitant population. The proposed recommendations for each country can identify the target population for designing effective vaccine communication strategies.
Subject(s)
COVID-19ABSTRACT
Background: Emerging respiratory infections threaten the global population, especially as we are experiencing the COVID-19 Pandemic. Such novel respiratory infections usually target the young adult population. In Malawi, the national surveillance system is in place, but no evidence to know if we can capture their incidents at the community level. Little is known about adults' acute respiratory illness (ARI) health-seeking behaviour in Malawi and Africa, as it is usually the presented symptom when these novel respiratory pathogens attack young adults. Our study was to fill the knowledge gap to understand the adult's health-seeking behaviour and pathway to guide future surveillance system enhancement. Methods: This was a qualitative study in which we applied a focus ethnographical methodology with a grounded approach to collect data from formal health service providers from the facility and community level, general adults from the community and traditional healers to triangulate the study aims. The study was conducted in a rural area of northern Malawi during 2016-2018. We used Colvin's model as the initial framework for data analysis to understand the adult ARI health-seeking behaviour process and the roles of different social actors along the path. Results: After the analysis, we considered that self-cognition and constant evaluation of the severity is a constant process determining an adult's decision to access formal services. Homemade remedies, especially herbal medicines, were widely used by adults as the immediate response to the illness. Among the other two processes, surrounding social actors played a role when negotiating support for accessing formal biomedical service, while the "middle layer" was the main process patient used prior to accessing services at facilities. The ARI incidents and mortality surveillance gaps exist at community and facility levels. Conclusions: Health surveillance assistants could fulfil their community surveillance function by expanding their care and treatment capacity. Furthermore, future surveillance system enhancement shall consider engaging drug vendors and traditional healers inclusively to become an essential event-based surveillance data source from the community. The ongoing development of the digital health systems in the country shall also provide its readiness for emerging respiratory infection surveillance.
Subject(s)
COVID-19 , Respiratory Tract Infections , Respiratory InsufficiencyABSTRACT
We tracked the effective reproduction number Rt of Omicron BF.7 in Beijing in November - December 2022 by fitting a transmission dynamic model parameterized with real-time mobility data to (i) the daily number of new symptomatic cases on November 1-11 (when the zero-covid interventions were still strictly enforced) and (ii) the proportion of individuals who participated in online polls on December 10-14 and self-reported to have been previously test-positive. After the announcement of "20 measures", we estimated that Rt increased to 3.42 (95% CrI: 2.79 - 4.17) on November 18. Infection incidence peaked on December 10, and the cumulative infection attack rate was 42.5% (95% CrI: 20.3 - 63.9) on December 14. Surveillance programmes should be rapidly set up to monitor the evolving epidemiology and evolution of SARS-CoV-2 across China.
ABSTRACT
We tracked the effective reproduction number Rt of Omicron BF.7 in Beijing in November – December 2022 by fitting a transmission dynamic model parameterized with real-time mobility data to (i) the daily number of new symptomatic cases on November 1–11 (when the zero-covid interventions were still strictly enforced) and (ii) the proportion of individuals who participated in online polls on December 10–14 and self-reported to have been previously test-positive. After the announcement of “20 measures”, we estimated that Rt increased to 3.42 (95% CrI: 2.79–4.17) on November 18. Infection incidence peaked on December 10, and the cumulative infection attack rate was 42.5% (95% CrI: 20.3–63.9) on December 14. Surveillance programmes should be rapidly set up to monitor the evolving epidemiology and evolution of SARS-CoV-2 across China.
ABSTRACT
Background Since the initial Wuhan outbreak, China has been containing COVID-19 outbreaks through its "dynamic zero-COVID" policy. Striking a balance between sustainability and cost-benefit, China has recently begun to adjust its COVID-19 response strategies, e.g. by announcing the "20 measures" on 11 November and further the "10 measures" on 7 December 2022. Strategies for safely exiting from dynamic zero-COVID (i.e. without catastrophically overburdening health systems and/or incurring unacceptably excessive morbidity and mortality) are urgently needed. Methods We use simulations to assess the respective and combined effectiveness of fourth-dose heterologous boosting, large-scale antiviral treatment and public health and social measures (PHSMs) that might allow China to further adjust COVID-19 response and exit from zero-COVID safely after 7 December 2022. We also assess whether local health systems can cope with the surge of COVID-19 cases posed by reopening, given that chunyun, a 40-day period with extremely high mobility across China associated with Spring Festival, will begin on 7 January 2023. Findings Reopening against Omicron transmission should be supported by the following interventions: 1) fourth-dose heterologous boosting 30-60 days before reopening by vaccinating 4-8% of the population per week with [≥]85% uptake across all ages; 2) timely antiviral treatment with [≥]60% coverage; 3) moderate PHSMs to reduce transmissibility by 47-69%. With fourth-dose vaccination coverage of 85% and antiviral coverage of 60%, the cumulative mortality burden would be reduced by 26-35% to 448-503 per million, compared with reopening without any of these interventions. Simultaneously reopening all provinces under current PHSMs would still lead to hospitalization demand that are 1.5-2.5 times of surge hospital capacity (2.2 per 10,000 population per day). Interpretation Although the surge of disease burden posed by reopening in December 2022-January 2023 would likely overload many local health systems across the country, the combined effect of vaccination, antiviral treatment and PHSMs could substantially reduce COVID-19 morbidity and mortality as China transits from dynamic-zero to normality. Planning for such a nationwide, coordinated reopening should be an urgent priority as part of the global exit from the acute phase of the COVID-19 pandemic.
Subject(s)
COVID-19ABSTRACT
Massive sequencing of SARS-CoV-2 genomes has led to a great demand for adding new samples to a reference phylogeny instead of building the tree from scratch. To address such challenge, we proposed an algorithm ‘TIPars’ by integrating parsimony analysis with pre-computed ancestral sequences. Compared to four state-of-the-art methods on four benchmark datasets (SARS-CoV-2, Influenza virus, Newcastle disease virus and 16S rRNA genes), TIPars achieved the best performance in most tests. It took only 21 seconds to insert 100 SARS-CoV-2 genomes to a 100k-taxa reference tree using near 1.4 gigabytes of memory. Its efficient and accurate phylogenetic placements and incrementation for phylogenies with highly similar and divergent sequences suggest that it will be useful in a wide range of studies including pathogen molecular epidemiology, microbiome diversity and systematics.
Subject(s)
Newcastle DiseaseABSTRACT
Both inactivated vaccine (CoronaVac; Sinovac) and mRNA vaccine (Comirnaty/BNT162b2; Fosun-Pharma/BioNTech) are available in Hong Kong’s COVID-19 Vaccination Programme. We reported waning antibody levels by enzyme-linked immunosorbent assays (ELISA) and surrogate virus neutralization test (sVNT) among 850 fully vaccinated blood donors (i.e., received two doses). The BNT162b2 group’s antibody levels remain over the 50% protection threshold within six months, and the CoronaVac’s group’s median antibody levels begin to fall below the 50% protection threshold two months after vaccination.
Subject(s)
COVID-19ABSTRACT
Background We aimed to evaluate the impact of various allocation strategies of COVID-19 vaccines and antiviral such that the pandemic exit strategy could be tailored to risks and preferences of jurisdictions in the East Asia and Pacific region (EAP) to improve its efficiency and effectiveness. Methods Vaccine efficacies were estimated from the titre distributions of 50% plaque reduction neutralization test (PRNT50), assuming that PRNT50 titres of primary vaccination decreased by 2-10 folds due to antibody waning and emergence of VOCs, and an additional dose of vaccine would increase PRNT50 titres by 3- or 9-fold. We then used an existing SARS-CoV-2 transmission model to assess the outcomes of vaccine allocation strategies with and without the use of antivirals for symptomatic patients in Japan, Hong Kong and Vietnam. Findings Increasing primary vaccination coverage was the most important contributing factor in reducing the total and peak number of COVID-19 hospitalizations, especially when population vaccine coverage or vaccine uptake among older adults was low. Providing antivirals to 50% of symptomatic infections only further reduced total and peak hospitalizations by 10-13%. The effectiveness of an additional dose of vaccine was highly dependent on the immune escape potential of VOCs and antibody waning, but less dependent on the boosting efficacy of the additional dose. Interpretation Increasing primary vaccination coverage should be prioritised in the design of allocation strategies of COVID-19 vaccines and antivirals in the EAP region. Heterologous vaccination with any available vaccine as the additional dose could be considered when planning pandemic exit strategies tailored to the circumstances of EAP jurisdictions. Funding Health and Medical Research Fund, General Research Fund, AIR@InnoHK
Subject(s)
COVID-19ABSTRACT
Background Transmission of respiratory pathogens such as SARS-CoV-2 depends on patterns of contact and mixing across populations. Understanding this is crucial to predict pathogen spread and the effectiveness of control efforts. Most analyses of contact patterns to date have focussed on high-income settings. Methods Here, we conduct a systematic review and individual-participant meta-analysis of surveys carried out in low- and middle-income countries and compare patterns of contact in these settings to surveys previously carried out in high-income countries. Using individual-level data from 28,503 participants and 413,069 contacts across 27 surveys we explored how contact characteristics (number, location, duration and whether physical) vary across income settings. Results Contact rates declined with age in high- and upper-middle-income settings, but not in low-income settings, where adults aged 65+ made similar numbers of contacts as younger individuals and mixed with all age-groups. Across all settings, increasing household size was a key determinant of contact frequency and characteristics, but low-income settings were characterised by the largest, most intergenerational households. A higher proportion of contacts were made at home in low-income settings, and work/school contacts were more frequent in high-income strata. We also observed contrasting effects of gender across income-strata on the frequency, duration and type of contacts individuals made. Conclusions These differences in contact patterns between settings have material consequences for both spread of respiratory pathogens, as well as the effectiveness of different non-pharmaceutical interventions. Funding This work is primarily being funded by joint Centre funding from the UK Medical Research Council and DFID (MR/R015600/1).
Subject(s)
Communicable DiseasesABSTRACT
As of February 13, 2020, there have been 59,863 laboratory-confirmed cases of COVID-19 infections in mainland China, including 1,367 deaths. A key public health priority during the emergence of a novel pathogen is estimating clinical severity. Here we estimated the symptomatic case-fatality risk (sCFR; the probability of dying from the infection after developing symptoms) of COVID-19 in Wuhan using public and published information. We estimated that sCFR was 0.5% (0.1%-1.3%), 0.5% (0.2%-1.1%) and 2.7% (1.5%-4.7%) for those aged 15-44, 45-64 and >64 years. The overall sCFR among those aged ≥15 years was 1.4% (0.8%-2.0%). Authors Joseph T Wu and Kathy Leung contributed equally to this work