SARS-CoV-2 Screening Test for Japanese Returnees From Wuhan, China, January 2020

Nationwide Descriptive Epidemiological Study of Patients with COVID-19 Evacuated from Wuhan, China to Japan from January to February, 2020

We investigated the epidemiological findings regarding the route of coronavirus disease 2019 (COVID-19) and infection prevention and control (IPC) measures among returnees in the emergency evacuation from Wuhan, China to Japan during the COVID-19 outbreak in 2020. A total of 12 of the 14 returnees (median age [range]: 49.5 years [29-65 years]; 9 men [75%]) had confirmed COVID-19. The proportion of returnees with COVID-19 was 12/566 (2.1%) in Flights 1-3 and 2/263 (0.8%) in Flights 4 and 5. Six patients were asymptomatic on admission, while 3 patients developed symptoms thereafter. None of the participants reported a specific history of contact with animals, going to seafood markets, or visiting medical facilities. Two patients were in contact with an individual who was confirmed or suspected of having COVID-19. Most patients resided in hotels in the center of Wuhan City, taking taxis and trains for commute. Patients relatively adhered to IPC measures such as wearing a mask and hand hygiene. However, emphasis on IPC measures such as universal masking and more rigorous avoidance of exposure risk might have been necessary to prevent infection. In addition, forced social distancing due to lockdown might have contributed to the lower infection rates in Flights 4 and 5, compared to Flights 1-3.

Association Between Air Pollution, Climate Change, and COVID-19 Pandemic: A Review of the Recent Scientific Evidence

Background: Recent studies indicated the possible relationship between climate change, environmental pollution, and Coronavirus Disease 2019 (COVID-19) pandemic. This study reviewed the effects of air pollution, climate parameters, and lockdown on the number of cases and deaths related to COVID-19. Methods: The present review was performed to determine the effects of weather and air pollution on the number of cases and deaths related to COVID-19 during the lockdown. Articles were collected by searching the existing online databases, such as PubMed, Science Direct, and Google Scholar, with no limitations on publication dates. Afterwards, this review focused on outdoor air pollution, including PM2.5, PM10, NO2, SO2, and O3, and weather conditions affecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)/COVID-19. Results: Most reviewed investigations in the present study showed that exposure to air pollutants, particularly PM2.5 and NO2, is positively related to COVID-19 patients and mortality. Moreover, these studies showed that air pollution could be essential in transmitting COVID-19. Local meteorology plays a vital role in coronavirus spread and mortality. Temperature and humidity variables are negatively correlated with virus transmission. The evidence demonstrated that air pollution could lead to COVID-19 transmission. These results support decision-makers in curbing potential new outbreaks. Conclusions: Overall, in environmental perspective-based COVID-19 studies, efforts should be accelerated regarding effective policies for reducing human emissions, bringing about air pollution and weather change. Therefore, using clean and renewable energy sources will increase public health and environmental quality by improving global air quality.

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: Update of a living systematic review and meta-analysis

BACKGROUND

Debate about the level of asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection continues. The amount of evidence is increasing and study designs have changed over time. We updated a living systematic review to address 3 questions: (1) Among people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) What is the infectiousness of asymptomatic and presymptomatic, compared with symptomatic, SARS-CoV-2 infection? (3) What proportion of SARS-CoV-2 transmission in a population is accounted for by people who are asymptomatic or presymptomatic?

METHODS AND FINDINGS

The protocol was first published on 1 April 2020 and last updated on 18 June 2021. We searched PubMed, Embase, bioRxiv, and medRxiv, aggregated in a database of SARS-CoV-2 literature, most recently on 6 July 2021. Studies of people with PCR-diagnosed SARS-CoV-2, which documented symptom status at the beginning and end of follow-up, or mathematical modelling studies were included. Studies restricted to people already diagnosed, of single individuals or families, or without sufficient follow-up were excluded. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with a bespoke checklist and modelling studies with a published checklist. All data syntheses were done using random effects models. Review question (1): We included 130 studies. Heterogeneity was high so we did not estimate a mean proportion of asymptomatic infections overall (interquartile range (IQR) 14% to 50%, prediction interval 2% to 90%), or in 84 studies based on screening of defined populations (IQR 20% to 65%, prediction interval 4% to 94%). In 46 studies based on contact or outbreak investigations, the summary proportion asymptomatic was 19% (95% confidence interval (CI) 15% to 25%, prediction interval 2% to 70%). (2) The secondary attack rate in contacts of people with asymptomatic infection compared with symptomatic infection was 0.32 (95% CI 0.16 to 0.64, prediction interval 0.11 to 0.95, 8 studies). (3) In 13 modelling studies fit to data, the proportion of all SARS-CoV-2 transmission from presymptomatic individuals was higher than from asymptomatic individuals. Limitations of the evidence include high heterogeneity and high risks of selection and information bias in studies that were not designed to measure persistently asymptomatic infection, and limited information about variants of concern or in people who have been vaccinated.

CONCLUSIONS

Based on studies published up to July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious than symptomatic infections. Summary estimates from meta-analysis may be misleading when variability between studies is extreme and prediction intervals should be presented. Future studies should determine the asymptomatic proportion of SARS-CoV-2 infections caused by variants of concern and in people with immunity following vaccination or previous infection. Without prospective longitudinal studies with methods that minimise selection and measurement biases, further updates with the study types included in this living systematic review are unlikely to be able to provide a reliable summary estimate of the proportion of asymptomatic infections caused by SARS-CoV-2.

REVIEW PROTOCOL

Open Science Framework (https://osf.io/9ewys/).

Asymptomatic SARS-CoV-2 infection: A systematic review and meta-analysis

Quantification of asymptomatic infections is fundamental for effective public health responses to the COVID-19 pandemic. Discrepancies regarding the extent of asymptomaticity have arisen from inconsistent terminology as well as conflation of index and secondary cases which biases toward lower asymptomaticity. We searched PubMed, Embase, Web of Science, and World Health Organization Global Research Database on COVID-19 between January 1, 2020 and April 2, 2021 to identify studies that reported silent infections at the time of testing, whether presymptomatic or asymptomatic. Index cases were removed to minimize representational bias that would result in overestimation of symptomaticity. By analyzing over 350 studies, we estimate that the percentage of infections that never developed clinical symptoms, and thus were truly asymptomatic, was 35.1% (95% CI: 30.7 to 39.9%). At the time of testing, 42.8% (95% prediction interval: 5.2 to 91.1%) of cases exhibited no symptoms, a group comprising both asymptomatic and presymptomatic infections. Asymptomaticity was significantly lower among the elderly, at 19.7% (95% CI: 12.7 to 29.4%) compared with children at 46.7% (95% CI: 32.0 to 62.0%). We also found that cases with comorbidities had significantly lower asymptomaticity compared to cases with no underlying medical conditions. Without proactive policies to detect asymptomatic infections, such as rapid contact tracing, prolonged efforts for pandemic control may be needed even in the presence of vaccination.

In-flight transmission of wild-type SARS-CoV-2 and the outbreak potential of imported clusters of COVID-19: a review of published evidence

International air travel has been highlighted as a concern since the beginning of the COVID-19 pandemic with respect to importation of cases. We summarise the available evidence for in-flight transmission of wild type SARS-CoV-2 during 2020, and for imported COVID-19 clusters to cause outbreaks. This paper provides a data baseline prior to the emergence of new mutations causing SARS-CoV-2 variants of concern, whose characteristics may increase the potential risk of in-flight transmission and imported outbreaks. The evidence on in-flight transmission of wild-type SARS-CoV-2 is limited, and is described in a small number of published reports. Most of the available evidence pertains to the early phase of the COVID-19 pandemic, during a period without non-pharmaceutical interventions such as distancing and in-flight mask wearing. There is considerable potential for outbreaks of COVID-19 from imported cases or clusters when public health guidance around quarantine of travellers and self-isolation of cases is not adhered to. Risks can be mitigated by measures such as: avoiding non-essential travel, targeted testing and quarantine of travellers from high incidence regions or regions of concern, managed quarantine processes, and protocols for rapid investigation and control of transmission from a possible variant of concern. Measures should be dynamically assessed and proportionate to the level of risk.

Assessing the Level of Awareness of COVID-19 and Prevalence of General Anxiety Disorder among the Hail Community, Kingdom of Saudi Arabia

BACKGROUND

The COVID-19 pandemic has caused a major public health problem around the world. Therefore, the aim of the study was to assess the awareness and prevalence of General Anxiety Disorder (GAD) with regard to COVID-19 among the Hail community, in the Kingdom of Saudi Arabia, in order to help health authorities to effectively control the pandemic.

METHODS

A cross-sectional online survey was completed by 412 participants living in Hail, Saudi Arabia. The questionnaire assessed demographic characteristics, knowledge, attitudes, and practices for the prevention of COVID-19, as well as psychological feelings in terms of GAD as an impact of the COVID-19 pandemic.

RESULTS

The study found that most of the respondents demonstrated good knowledge, attitudes, and practice for COVID-19 prevention. The elderly and employed demonstrated significant positive attitudes and practices (p < 0.05). Participants with a positive attitude were almost two and a half times (OR = 2.4; 95% CI: 1.54-3.99) more likely to have good practices. Additionally, the rural respondents were less likely (OR = 0.45; 95% CI: 0.21-0.96) to have a positive attitude. Married participants were more than one and a half (OR = 1.60; 95% CI: 1.04-2.44) times more likely to have a positive attitude. The prevalence of GAD was 21.8% and was significantly increased among participants with inadequate knowledge (OR = 2.01; 95% CI: 1.25-3.22), females (OR = 1.92; 95% CI: 1.19-3.09), individuals with chronic diseases (OR = 1.71; 95% CI: 1.02-2.86), and non-Saudi participants (OR = 2.44; 95% CI: 1.02-5.85).

CONCLUSIONS

Ensuring a sufficient combination of relatively good levels of knowledge, positive attitudes, and desired practices serves as a good approach to preventing the spread of COVID-19. However, the increased prevalence of GAD requires the attention of policymakers. Therefore, a great emphasis should be placed on health awareness campaigns, with a focus on misconceptions and the provision of counseling.

The Proportion of SARS-CoV-2 Infections That Are Asymptomatic : A Systematic Review

BACKGROUND

Asymptomatic infection seems to be a notable feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes coronavirus disease 2019 (COVID-19), but the prevalence is uncertain.

PURPOSE

To estimate the proportion of persons infected with SARS-CoV-2 who never develop symptoms.

DATA SOURCES

Searches of Google News, Google Scholar, medRxiv, and PubMed using the keywords antibodies, asymptomatic, coronavirus, COVID-19, PCR, seroprevalence, and SARS-CoV-2.

STUDY SELECTION

Observational, descriptive studies and reports of mass screening for SARS-CoV-2 that were either cross-sectional or longitudinal in design; were published through 17 November 2020; and involved SARS-CoV-2 nucleic acid or antibody testing of a target population, regardless of current symptomatic status, over a defined period.

DATA EXTRACTION

The authors collaboratively extracted data on the study design, type of testing performed, number of participants, criteria for determining symptomatic status, testing results, and setting.

DATA SYNTHESIS

Sixty-one eligible studies and reports were identified, of which 43 used polymerase chain reaction (PCR) testing of nasopharyngeal swabs to detect current SARS-CoV-2 infection and 18 used antibody testing to detect current or prior infection. In the 14 studies with longitudinal data that reported information on the evolution of symptomatic status, nearly three quarters of persons who tested positive but had no symptoms at the time of testing remained asymptomatic. The highest-quality evidence comes from nationwide, representative serosurveys of England (n = 365 104) and Spain (n = 61 075), which suggest that at least one third of SARS-CoV-2 infections are asymptomatic.

LIMITATION

For PCR-based studies, data are limited to distinguish presymptomatic from asymptomatic infection. Heterogeneity precluded formal quantitative syntheses.

CONCLUSION

Available data suggest that at least one third of SARS-CoV-2 infections are asymptomatic. Longitudinal studies suggest that nearly three quarters of persons who receive a positive PCR test result but have no symptoms at the time of testing will remain asymptomatic. Control strategies for COVID-19 should be altered, taking into account the prevalence and transmission risk of asymptomatic SARS-CoV-2 infection.

PRIMARY FUNDING SOURCE

National Institutes of Health.

The Flight Evacuation Mission for COVID-19 from Wuhan, China to Tokyo, Japan from January 28 to February 17, 2020

Multiple countries have reported evacuation missions to repatriate their citizens in the early phase of the emergence of COVID-19 from China. However, a paucity of data exists on how to optimally execute an evacuation while balancing the risk of transmission during the flight and avoiding spread to the evacuees' home countries. We describe the collective findings of the flight evacuation mission from Wuhan, China to Tokyo, Japan from January 28 to February 17, 2020. The evacuation team established the evacuation processing flow, including a focused health questionnaire, temperature monitoring, ticketing and check-in, and boarding procedure planning. The evacuees were seated according to pre-planned zones. Additionally, to facilitate the triage of evacuees for medical needs, we conducted in-flight quarantine to determine the disposition of the evacuees. All evacuees, regardless of their health condition, were required to perform rigorous hand hygiene frequently and to wear surgical masks throughout the flight. We implemented strict infection prevention and control throughout the mission, including in-flight quarantine. The pre-planned protocol and vigilant observation during the flight were crucial elements of this mission. Our experience is of value in developing a more refined plan for the next outbreak.

Lessons Learned from Japan's Response to the First Wave of COVID-19: A Content Analysis

While the epidemiological impact of the coronavirus disease 2019 (COVID-19) pandemic has been relatively moderate in East-Asian countries, the pandemic has significantly impacted on citizens' lives and livelihoods, and Japan is no exception. In the early phase of the COVID-19 pandemic, Japan managed unprecedented quarantines and realized the difficulty of controlling COVID-19, finally recording a relatively high number of deaths per million in the Western Pacific region. However, scant research has highlighted the distinctive features of Japan's reaction and the challenges encountered. To clarify these points and examine Japan's first response to COVID-19, we performed a content analysis. Minutes of expert meetings were analyzed from multiple viewpoints, including epidemiology, health systems, border control, and health communication. The obscure evolution of the testing strategy, the usefulness of retrospective contact tracing, the rapid scientific risk assessment, a sluggish expansion of health system capacity and response in border control, and misunderstanding between risk communication and crisis communication are made evident by our analysis. Examining previous responses and gathering lessons learned in each country will improve global responses to COVID-19 and strengthen regional health security. Therefore, while investing in public health and ensuring transparency, Japan needs to clarify the previous decision-making process of each countermeasure towards COVID-19.

Severe Acute Respiratory Syndrome Coronavirus 2 Infection among Returnees to Japan from Wuhan, China, 2020

In early 2020, Japan repatriated 566 nationals from China. Universal laboratory testing and 14-day monitoring of returnees detected 12 cases of severe acute respiratory syndrome coronavirus 2 infection; initial screening results were negative for 5. Common outcomes were remaining asymptomatic (n = 4) and pneumonia (n = 6). Overall, screening performed poorly.