Decreased Influenza Vaccination Coverage among Chinese Healthcare Workers during the COVID-19 pandemic (preprint)

Background: Healthcare workers were the priority group for influenza vaccination, however, the vaccination rate among them in China had always been low. This study was conducted to investigate the influenza vaccination status among Chinese healthcare workers (HCWs) during the 2020/2021 and 2021/2022 influenza seasons and analyze the factors driving vaccination. Methods We provided Electronic questionnaires to the healthcare workers from January 27, 2022 to February 21, 2022 using the WeChat platform "Breath Circles". Binary logistic regression models were used to analyze the factors associated with vaccination among healthcare workers. Results Among the 1697 healthcare workers surveyed, the vaccination coverage during the 2020/2021 and 2021/2022 influenza seasons was 43.67% (741/1697) and 35.36% (600/1697), respectively. Additionally, during the 2020/2021 and 2021/2022 influenza seasons, only 22.69% (385/1697) and 22.10% (358/1697) surveyed healthcare workers reported that their workplaces implemented the free vaccination policy for all employees, respectively. Conclusions Free influenza vaccination policy and workplace mandatory vaccination are effective in improving the influenza vaccination coverage in healthcare workers. The Chinese healthcare workers’ influenza vaccination coverage remained low and showed a downward trend after the outbreak of the COVID-19 pandemic. Further effective measures should be taken to improve influenza vaccination coverage.

Influenza’s plummeting and future dynamics: the roles of mask wearing, mobility change and SARS-CoV-2 interference (preprint)

Untangling lessons from the influenza’s plummeting during the COVID-19 pandemic is critical for mitigating seasonal and pandemic influenza. Here we explored a country-specific inference model to estimate the effects of mask-wearing, mobility changes (international and domestic) and SARS-CoV-2 interference in China, England and the United States. We found that mask wearing had a larger reduction than mobility changes in all the regions. Only in 2019-2020, SARS-CoV-2 interference had an observable effect, with values varying at the timing of the influenza season and the speed of SARS-CoV-2 community transmission. Compared to the epidemics in 2017–2019, longer and blunter rebounds could occur in the incoming 2021–2022 season, but the rebound would be smaller if less stringent mask mandates continued or the international mobility stayed low. Our results bear implications for understanding how influenza evolves under non-pharmaceutical interventions and other respiratory diseases, and will inform designing of tailored public health measures.

Risk Factors of SARS-CoV-2 and Follow-up in Patients with Common Underlying Diseases on the Dynamic Changes of Antibodies: A Cross-sectional Study (preprint)

Background: Assessing the humoral immunity of patients with underlying diseases after being infected with SARS-CoV-2 is essential for determining effective prevention and control strategies. The purpose of this study is to investigate whether underlying disease is a risk factor for SARS-CoV-2 infection, reveal the seroprevalence of people with underlying disease and the characteristics of dynamic changes in anti-SARS-CoV-2 antibodies, and provide evidence for the scientific formulation of COVID-19 vaccination strategies. Methods: : The probability ratio sampling method was adopted to systematically select 100 communities from 13 districts in Wuhan, China, followed by a random selection of households from 100 communities according to a list provided by the local government. Individuals who have lived in Wuhan for at least 14 days since December 2019 and were ≥40 years old were included. Individuals with other serious diseases besides COVID-19, from whom a sample could not be obtained or refused to participate, were excluded. All eligible subjects signed a written informed consent form and completed a standardized electronic questionnaire before being enrolled in the group. From April 9–13, 2020, venous blood samples were collected from all individuals; from June 11–13, 2020, and from October 9–December 5, 2020, all positive and matched negative families were followed up. Results: : The seroprevalence of SARS-CoV-2 in people with underlying diseases was 6.30% (95% CI [5.09-7.52]), and that of people without underlying diseases was 6.12% (95% CI [5.33-6.91]). Among people with underlying diseases, retirees, health workers, and people who have been exposed to fever or respiratory symptoms since December 2019 were more likely to be infected with SARS-CoV-2. The IgG titer of people with underlying disease decreased significantly over time (P <0.05), but the neutralizing antibody titer remained relatively stable throughout the follow-up period. There was no significant difference between the IgG titer decline rate of people with underlying disease and those without. The IgG titer of people with underlying disease and asymptomatic infection was lower than that in symptomatic infection. Conclusion: These findings imply that vaccination strategies for people with and without underlying diseases may not require special adjustments.

The Effects of Mask Wearing, Mobility Change and SARS-CoV-2 Interference on Seasonal Influenza in Northern China, Southern China, England, and the United States (preprint)

Background: Seasonal influenza activity typically peaks in winter months but plummets globally during the COVID-19 pandemic. Untangling lessons from the influenza’s unprecedented low profile is critical for informing preparedness for incoming influenza seasons.Methods: We collect data from public sources in Northern China, Southern China, England and the United States. We estimate the individual effects of mask-wearing, mobility change (international and domestic) and SARS-CoV-2 interference, and forecast the influenza activity in the incoming 2021–2022 influenza season, using a country-specific inference model.Findings: The one-week increase of the mask-wearing intervention has a percent reduction of 11·3% to 35·2% on influenza activity in the four regions. The one-week mobility mitigation has smaller effects, 1·7% to 6·5% for the international and 1·6% to 2·8% for the domestic. In 2020–2021, the mask-wearing intervention alone could decline 13·3 to 19·8 percent positivity. The mobility change alone could reduce 5·2 to 14·0 percent positivity, of which 79·8% to 98·2% are attributed to the deflected international travel. Only in 2019–2020, SARS-CoV-2 interference has statical significant effects, and in Northern China and England only, reducing 7·6 (2·4 to 14·4) and 10·2 (7·2 to 13·6) percent positivity respectively. Compared to the epidemics in 2017–2019, longer and blunter rebounds could occur in the incoming 2021–2022 season should the mask-wearing be lifted, but the rebound would be smaller if the international mobility stayed low.Interpretation: Mask-wearing is more effective than mobility mitigation in all the four regions, although the relative advantage depends on the timing and duration of the interventions. Effects of SARS-CoV-2 interference vary at the timing of the influenza season and the speed of SARS-CoV-2 community transmission. The results improve our understandings of nonpharmaceutical interventions and other respiratory disease on influenza, and will inform the tailored public health measures for mitigating seasonal influenza and future pandemics.Funding: National Natural Science Foundation, Chinese Academy of Medical Sciences & Peking Union Medical College, and the Bill & Melinda Gates FoundationDeclaration of Interest: The authors declare no competing interests.

Effects of worldwide interventions and vaccination on COVID-19 between waves and countries (preprint)

Worldwide governments have rapidly deployed non-pharmaceutical interventions (NPIs) to mitigate the COVID-19 pandemic, together with the large-scale rollout of vaccines since late 2020. However, the effect of these individual NPI and vaccination measures across space and time has not been sufficiently explored. By the decay ratio in the suppression of COVID-19 infections, we investigated the performance of different NPIs across waves in 133 countries, and their integration with vaccine rollouts in 63 countries as of 25 March 2021. The most effective NPIs were gathering restrictions (contributing 27.83% in the infection rate reductions), facial coverings (16.79%) and school closures (10.08%) in the first wave, and changed to facial coverings (30.04%), gathering restrictions (17.51%) and international travel restrictions (9.22%) in the second wave. The impact of NPIs had obvious spatiotemporal variations across countries by waves before vaccine rollouts, with facial coverings being one of the most effective measures consistently. Vaccinations had gradually contributed to the suppression of COVID-19 transmission, from 0.71% and 0.86% within 15 days and 30 days since Day 12 after vaccination, to 1.23% as of 25 March 2021, while NPIs still dominated the pandemic mitigation. Our findings have important implications for continued tailoring of integrated NPI or NPI-vaccination strategies against future COVID-19 waves or similar infectious diseases.

Impacts of worldwide individual non-pharmaceutical interventions on COVID-19 transmission across waves and space (preprint)

Governments worldwide have rapidly deployed non-pharmaceutical interventions (NPIs) to mitigate the COVID-19 pandemic. However, the effect of these individual NPI measures across space and time has yet to be sufficiently assessed, especially with the increase of policy fatigue and the urge for NPI relaxation in the vaccination era. Using the decay ratio in the suppression of COVID-19 infections, we investigated the changing performance of different NPIs across waves from global and regional levels (in 133 countries) to national and subnational (in the United States of America [USA]) scales before the implementation of mass vaccination. The synergistic effectiveness of all NPIs for reducing COVID-19 infections declined along waves, from 95.4% in the first wave to 56.0% in the third wave recently at the global level and similarly from 83.3% to 58.7% at the USA national level, while it had fluctuating performance across waves on regional and subnational scales. Regardless of geographical scale, gathering restrictions and facial coverings played significant roles in epidemic mitigation before the vaccine rollout. Our findings have important implications for continued tailoring and implementation of NPI strategies, together with vaccination, to mitigate future COVID-19 waves, caused by new variants, and other emerging respiratory infectious diseases.

Integrated vaccination and physical distancing interventions to prevent future COVID-19 waves (preprint)

COVID-19 resurgences worldwide have posed significant challenges to the formulation of preventive interventions, especially given that the effects of physical distancing and upcoming vaccines on reducing susceptible social contacts and eventually halting transmission are still unclear. Using anonymized mobile geolocation data in China, we devised a mobility-associated social contact index to quantify the impact of both physical distancing and vaccination measures in a unified way such that the gap between intervention measures and disease transmission can be explicitly bridged. This index explained 90% of the variance in the changing reproduction number of infections across the COVID-19 outbreak in Wuhan, and was validated in six other cities of different population densities. Our simulations showed that vaccination combined with physical distancing can contain resurgences without relying on mobility reduction, whereas a gradual vaccination process alone cannot achieve this. Further, for cities with medium-population density, vaccination can shorten the duration of physical distancing by 36%-78%, whereas for cities with high-population density, infection numbers can well be controlled through moderate physical distancing. These findings provide guidance on tailoring and implementing comprehensive interventions for cities with varying population densities.

Transmission risk of SARS-CoV-2 on airplanes and high-speed trains (preprint)

Modern transportation plays a key role in the long-distance and rapid spread of SARS-CoV-2. However, little is known about the transmission risk of SARS-CoV-2 on confined vehicles, such as airplanes and trains. Based on the itinerary and epidemiological data of COVID-19 cases and close contacts among 9,265 airline passengers on 291 airplanes and 29,335 passengers on 830 high-speed trains in China from December 20, 2019 to March 17, 2020, we estimated that the upper bound of overall attack rate of COVID-19 among passengers was 0.60% (95% confidence interval: 0.43%-0.84%) for airplanes and 0.35% (0.28%-0.44%) for trains departing from Wuhan before its lockdown, respectively. The reproduction number during travel ranged from 0.12 to 0.19 on airplanes and from 0.07 to 0.12 on trains, with the risk varying by seat distance from the index case and joint travel time, but the difference in risk was not significant between the types of aircraft and train. Overall, the risk of SARS-CoV-2 transmission on planes and high-speed trains with high efficiency air filtration devices was relatively low. Our findings improve understanding of COVID-19 spread during travel and may inform response efforts, such as lifting travel restrictions, and resuming transportation in the pandemic.

Seasonal association between viral causes of hospitalised acute lower respiratory infections and meteorological factors in China: a retrospective study (preprint)

Acute lower respiratory infections caused by respiratory viruses are common and persistent infectious diseases worldwide and in China, which have pronounced seasonal patterns. Meteorological factors have important roles in the seasonality of some major viruses. Our aim was to identify the dominant meteorological factors and to model their effects on common respiratory viruses in different regions of China. We analysed monthly virus data on patients from 81 sentinel hospitals in 22 provinces in mainland China from 2009 to 2013. The geographical detector method was used to quantify the explanatory power of each meteorological factor, individually and interacting in pairs. 28369 hospitalised patients with ALRI were tested, 10387 were positive for at least one virus, including RSV, influenza virus, PIV, ADV, hBoV, hCoV and hMPV. RSV and influenza virus had annual peaks in the north and biannual peaks in the south. PIV and hBoV had higher positive rates in the spring summer months. hMPV had an annual peak in winter spring, especially in the north. ADV and hCoV exhibited no clear annual seasonality. Temperature, atmospheric pressure, vapour pressure, and rainfall had most explanatory power on most respiratory viruses in each region. Relative humidity was only dominant in the north, but had no significant explanatory power for most viruses in the south. Hours of sunlight had significant explanatory power for RSV and influenza virus in the north, and for most viruses in the south. Wind speed was the only factor with significant explanatory power for human coronavirus in the south. For all viruses, interactions between any two of the paired factors resulted in enhanced explanatory power, either bivariately or non-linearly.

Effects of an Online Mindful Living With Challenge (MLWC) Intervention on Mental Health and Quality of Life Among COVID-19 Patients in China: A Protocol of a Randomized Controlled Trial (preprint)

Background COVID-19 can lead to increased psychological symptoms such as post-traumatic stress disorder (PTSD), depression, and anxiety, especially for patients with COVID-19. Studies suggest that mindfulness-based intervention is an effective, easily delivered and non-aggressive online therapy for patients with mental disorders. This study aims to explore the efficacy and possible mechanism of a Mindful Living With Challenge (MLWC) intervention designed for Chinese COVID-19 survivors in alleviating their psychological problems caused by both the disease and the pandemic.Methods This study is a protocol for a randomized controlled trial. More than 1600 eligible participants will be assigned 1:1 to an online MLWC intervention group or a waitlist control group. All participants will be asked to complete online questionnaires at baseline , post-program, and 3-month follow-up. The primary outcome is mental health status which includes PTSD and other psychological symptoms (i.e. depression, anxiety). The secondary outcomes are related physical symptoms including fatigue and sleeplessness assessed by verified scales such as the Fatigue Scale-14, Pittsburgh Sleep Quality Index. In addition, Five Facets Mindfulness Questionnaire, the Nonattachment Scale, the Stillness Scale, the Resilience Style Questionnaire and the Social Support Scale will be used to assess the mindfulness, stillness, nonattachment level, resilience and perceived social support before and after the intervention, which may be the possible mediators and moderators of the link between the MLWC intervention and target outcomes. Data will be analyzed based on an intention-to-treat approach, and SPSS software will be used to perform statistical analysis.Discussion This study will provide scientific evidence on the efficacy and possible mechanism of the MLWC intervention in improving the quality of life and psychological status among COVID-19 survivors in China. Findings from this study will contribute to a growing research field that assesses the effectiveness of mobile-based and theoretically guided interventions for improving the psychological status of the COVID-19 survivors. Moreover, findings from this study will also contribute to the prevention and management of the psychological complications patients face during such public health emergencies.Trial registration Chinese Clinical Trial Registry (ChiCTR), ChiCTR2000037524; Registered on August 29, 2020, http://www.chictr.org.cn/showproj.aspx?proj=60034. 

Assessing the effect of global travel and contact reductions to mitigate the COVID-19 pandemic and resurgence (preprint)

Travel and physical distancing interventions have been implemented across the World to mitigate the COVID-19 pandemic, but studies are needed to quantify the effectiveness of these measures across regions and time. Timely population mobility data were obtained to measure travel and contact reductions in 135 countries or territories. During the 10 weeks of March 22 - May 30, 2020, domestic travel in study regions has dramatically reduced to a median of 59% (interquartile range [IQR] 43% - 73%) of normal levels seen before the outbreak, with international travel down to 26% (IQR 12% - 35%). If these travel and physical distancing interventions had not been deployed across the World, the cumulative number of cases might have shown a 97-fold (IQR 79 - 116) increase, as of May 31, 2020. However, effectiveness differed by the duration and intensity of interventions and relaxation scenarios, with variations in case severity seen across populations, regions, and seasons.

Assessing spread risk of Wuhan novel coronavirus within and beyond China, January-April 2020: a travel network-based modelling study (preprint)

Background: A novel coronavirus (2019-nCoV) emerged in Wuhan City, China, at the end of 2019 and has caused an outbreak of human-to-human transmission with a Public Health Emergency of International Concern declared by the World Health Organization on January 30, 2020. Aim: We aimed to estimate the potential risk and geographic range of Wuhan novel coronavirus (2019-nCoV) spread within and beyond China from January through to April, 2020. Methods: A series of domestic and international travel network-based connectivity and risk analyses were performed, by using de-identified and aggregated mobile phone data, air passenger itinerary data, and case reports. Results: The cordon sanitaire of Wuhan is likely to have occurred during the latter stages of peak population numbers leaving the city before Lunar New Year (LNY), with travellers departing into neighbouring cities and other megacities in China. We estimated that 59,912 air passengers, of which 834 (95% UI: 478 - 1349) had 2019-nCoV infection, travelled from Wuhan to 382 cities outside of mainland China during the two weeks prior to the lockdown of Wuhan. The majority of these cities were in Asia, but major hubs in Europe, the US and Australia were also prominent, with strong correlation seen between predicted importation risks and reported cases. Because significant spread has already occurred, a large number of airline travellers (3.3 million under the scenario of 75% travel reduction from normal volumes) may be required to be screened at origin high-risk cities in China and destinations across the globe for the following three months of February to April, 2020 to effectively limit spread beyond its current extent. Conclusion: Further spread of 2019-nCoV within China and international exportation is likely to occur. All countries, especially vulnerable regions, should be prepared for efforts to contain the 2019-nCoV infection.