Comparison of control and transmission of COVID-19 across epidemic waves in Hong Kong: an observational study (preprint)

Background: Hong Kong contained COVID-19 for two years, but experienced a large epidemic of Omicron BA.2 in early 2022 and endemic transmission of Omicron subvariants thereafter. Methods: We examined the use and impact of pandemic controls in Hong Kong by analysing data on more than 1.7 million confirmed COVID-19 cases and characterizing non-pharmaceutical and pharmaceutical interventions implemented from January 2020 through to 30 December 2022. We estimated the daily effective reproductive number (Rt) to track changes in transmissibility and effectiveness of community-based measures against infection over time. We examined the temporal changes of pharmaceutical interventions, mortality rate and case-fatality risks (CFRs), particularly among older adults. Findings: Hong Kong experienced four local epidemic waves predominated by the ancestral strain in 2020 and early 2021 and prevented multiple SARS-CoV-2 variants from spreading in the community before 2022. Strict travel-related, case-based, and community-based measures were increasingly tightened in Hong Kong over the first two years of the pandemic. However, even very stringent measures were unable to contain the spread of Omicron BA.2 in Hong Kong. Despite high overall vaccination uptake (>70% with at least two doses), high mortality was observed during the Omicron BA.2 wave due to lower vaccine coverage (42%) among adults [≥]65 years of age. Increases in antiviral usage and vaccination uptake over time through 2022 was associated with decreased case fatality risks. Interpretation: Integrated strict measures were able to reduce importation risks and interrupt local transmission to contain COVID-19 transmission and disease burden while awaiting vaccine development and rollout. Increasing coverage of pharmaceutical interventions among high-risk groups reduced infection-related mortality and mitigated the adverse health impact of the pandemic.

Empirical study on improving international dry port competitiveness based on logistics supply chain integration: evidence from China

Purpose>The importance of international dry port integration in the supply chain has received a great deal of attention and been widely discussed in the literature. This study empirically examines the relationship among dry port logistics supply chain integration (DPLSCI), its operational performance (OP) and dry port competitiveness (DPC) in the context of China.Design/methodology/approach>The authors developed a structured questionnaire based on the supply chain integration (SCI) theory and resource-based view, and collected data from the dry port operation enterprises and their stakeholders in central and western China. A structural equation model (SEM) is used to test the research hypotheses.Findings>The results demonstrate that DPLSCI has a positive effect on logistics cost performance (LCP) and service quality performance (SQP), which further improves DPC. Meanwhile, OP (LCP and SQP) is a full mediator between DPLSCI and DPC.Practical implications>This paper provides guidelines for dry port operators and their stakeholders to integrate supply chain resources and develop the OP for improving the overall competitiveness of an international dry port. The government could also invest in physical infrastructure and system platform to strengthen the OP of a dry port and further enhance its competitiveness.Originality/value>The authors emphasise that the international dry port is a proactive and integrated system in providing a supply chain logistics service. This study fills up a research gap in the extant literature on theoretically proposing and empirically testing a new theoretical model. It also contributes to dry port stakeholders by providing useful guidelines to enhance OP and dry port competitiveness.

Modes of contact and risk of transmission in COVID-19 among close contacts (preprint)

Background Rapid spread of SARS-CoV-2 in Wuhan prompted heightened surveillance in Guangzhou and elsewhere in China. Modes of contact and risk of transmission among close contacts have not been well estimated. Methods We included 4950 closes contacts from Guangzhou, and extracted data including modes of contact, laboratory testing, clinical characteristics of confirmed cases and source cases. We used logistic regression analysis to explore the risk factors associated with infection of close contacts. Results Among 4950 closes contacts, the median age was 38.0 years, and males accounted for 50.2% (2484). During quarantine period, 129 cases (2.6%) were diagnosed, with 8 asymptomatic (6.2%), 49 mild (38.0%), and 5 (3.9%) severe to critical cases. The sensitivity of throat swab was 71.32% and 92.19% at first to second PCR test. Among different modes of contact, household contacts were the most dangerous in catching with infection of COVID-19, with an incidence of 10.2%. As the increase of age for close contacts and severity of source cases, the incidence of COVID-19 presented an increasing trend from 1.8% (0-17 years) to 4.2% (60 or over years), and from 0.33% for asymptomatic, 3.3% for mild, to 6.2% for severe and critical source cases, respectively. Manifestation of expectoration in source cases was also highly associated with an increased risk of infection in their close contacts (13.6%). Secondary cases were in general clinically milder and were less likely to have common symptoms than those of source cases. Conclusions In conclusion, the proportion of asymptomatic and mild infections account for almost half of the confirmed cases among close contacts. The household contacts were the main transmission mode, and clinically more severe cases were more likely to pass the infection to their close contacts. Generally, the secondary cases were clinically milder than those of source cases.