The development of depression and social anxiety symptoms in adolescents and the negative impact of the COVID-19 pandemic and desire for peer contact.

Introduction: Adolescence is a dynamic developmental phase in which contact with peers is crucial for socio-emotional development and wellbeing. Depression and social anxiety show patterns of high onset during this period, and more for girls than boys. Here we examine this development among Dutch adolescents, as well as how desire for more peer contact as a result of social distancing measures during the COVID-19 pandemic contributed to this increase. Methods: We used a longitudinal three-wave design to examine 406 typically developing Dutch adolescents across two consecutive cohorts; Cohort 1: 2016-2019 (N = 138, 53.6% girls, age at T0 M = 13.00, SD = 0.42), Cohort 2: 2017-2020 (N = 268, 63.1% girls, age at T0 M = 13.05, SD = 0.39), final wave during spring 2020 during the first COVID-19 lockdown. Self-report questionnaires were used to measure depression and social anxiety symptoms, desire for change in the amount of peer contact during lockdowns, and emotion regulation. Parallel process dual latent growth models and autoregressive cross-lagged models were used to test the hypotheses. Results: Results showed that symptoms of both depression and social anxiety increase during adolescence. Gender analysis reveal a higher initial level and increase in depression symptoms for girls, while levels for boys decreased. Adolescents exposed to the pandemic showed a steeper increase in depression but not in social anxiety. Desire for more peer contact was related to an increase in depression and social anxiety, though only in girls. No evidence was found for moderation of emotion regulation skills concerning COVID evoked emotions on the association between desire for peer contact and anxiety and depression symptom development. Discussion: Symptoms of social anxiety increased during adolescence in boys and girls. Symptoms of depression increased for girls, but decreased for boys. The increase in depression was greater in a cohort who experienced the COVID-19 pandemic. For girls, a desire for more peer contact was associated with an increase of depression and social anxiety symptoms in times of social restrictions.

Should I stay (home) or should I go (party)? Examination of drinking as a mediator of the relationship between alcohol-related social media content and adherence to COVID-19 recommendations among college students.

INTRODUCTION: The COVID-19 pandemic impacted young people's drinking. Yet, despite social gatherings posing a known risk for increased contraction, some college students still congregated to drink. Furthermore, some students posted about these drinking events to their public and/or private social media feeds. It is crucial to understand the relationships between posting alcohol-related content (ARC), drinking and adherence to COVID-19 recommendations because they may have contributed to the spread of the virus. METHODS: The current interval contingent, 14-day diary study assessed students' (N = 129) public and private ARC; their drinking; percentage of time wearing a mask and social distancing; and number of people they socialised with during drinking events (total crowd size) each day. RESULTS: Multilevel structural equation modelling was employed to examine relationships between ARC posting, drinking and behavioural outcomes. On days in which students posted both public and private ARC, they tended to drink more and in turn, reported attending gatherings with larger crowds. Curiously, on days in which students drank more, they indicated more mask wearing and social distancing, and on days in which students posted more private ARC, they also reported larger crowds. Finally, an indirect effect of drinking on the links between public and private ARC and mask wearing, social distancing and total crowd sizes emerged. DISCUSSION AND CONCLUSIONS: Findings revealed students continued to post and drink socially despite the risks, which may have encouraged others within their networks to engage in similar risky behaviours. Future public health crises should balance young people's need for social connection with risk mitigation efforts.

An examination of the influenza pandemic in early 20th century in Crete through the lens of the 1918 editions of Nea Ephimeris, a Cretan newspaper.

Crete, strategically situated at the crossroads of three continents, was historically embroiled in incessant conflicts between colonisers and Greek revolutionaries, as well as recurrent battles against disease. In 1918, the island faced a novel adversary: influenza. In response, the state, local authorities, and medical professionals on the island mounted a formidable defence. Hospitals, health centres, and the military all contributed to the effort. Essential provisions of medicine and food were distributed to support the populations in areas most inflicted. The Heraklion-based newspaper Nea Ephimeris played a crucial role in documenting these events. Through its articles, reports, interviews, and reviews of the influenza situation, it disseminated vital information that helped the public understand both preventive measures and the necessary actions to combat the spread of the virus. This study examines the coverage by Nea Ephimeris from January 1918 to January 1919, assessing how the newspaper informed, supported, and uplifted the urban and rural populations of Crete. The data collected reconstruct the events of that period and demonstrate how historical pandemics offer lessons that can prepare health professionals for future challenges.

Identifying Population Segments by Differing Levels of COVID-19 Vaccine Confidence and Evaluating Subsequent Uptake of COVID-19 Prevention Behaviors: Web-Based, Longitudinal, Probability-Based Panel Survey.

BACKGROUND: The COVID-19 pandemic prompted the launch of the US Department of Health and Human Services' COVID-19 Public Education Campaign to boost vaccine confidence and uptake among adults, as vaccines are key to preventing severe illness and death. OBJECTIVE: Past segmentation research relevant to COVID-19 behavior has found important differences in attitudes, sociodemographics, and subsequent COVID-19 prevention behaviors across population segments. This study extends prior work by incorporating a more comprehensive set of attitudes, behaviors, and sociodemographic variables to identify population segments by differing levels of COVID-19 vaccine confidence and evaluate differences in their subsequent uptake of COVID-19 prevention behaviors. METHODS: Data were obtained from 5 waves (January 2021 to June 2022) of a web-based longitudinal, probability-based panel survey of US adults (N=4398) administered in English and in Spanish. Participants were recruited from NORC at the University of Chicago's national AmeriSpeak panel and were invited to participate across multiple waves. Latent class cluster analysis estimated segments of respondents based on over 40 COVID-19 attitudes, beliefs, behaviors, and sociodemographics as reported in wave 1. Survey-weighted cross-tabulations and bivariate regression analyses assessed differences in COVID-19 vaccine uptake, booster uptake, mask use, and social distancing in all segments across all 5 survey waves. RESULTS: A total of 6 segments (hardline nonintenders, prevention-compliant nonintenders, burned-out waiters, anxious waiters, skeptical confidents, and ready confidents) were identified, which differed by their COVID-19 vaccine confidence, prevention-related attitudes and behaviors, and sociodemographics. Cross-tabulations and regression results indicated significant segment membership differences in COVID-19 vaccine and booster timing, mask use, and social distancing. Results from survey-weighted cross-tabulations comparing COVID-19 vaccine and booster uptake across segments indicate statistically significant differences in these outcomes across the 6 segments (P<.001). Results were statistically significant for each segment (P<.01 for booster uptake among burned-out waiters; P<.001 for all other coefficients), indicating that, on average, respondents in segments with lower intentions to vaccinate reported later receipt of COVID-19 vaccines and boosters relative to the timing of vaccine and booster uptake among ready confidents. CONCLUSIONS: Results extend previous research by showing that initial beliefs and behaviors relevant to COVID-19 vaccination, mask use, and social distancing are important for understanding differences in subsequent compliance with recommended COVID-19 prevention measures. Specifically, we found that across respondent segments, the probability of vaccine and booster uptake corresponded with both COVID-19 vaccine confidence and mask use and social distancing compliance; more compliant segments were more likely to get vaccinated or boosted than less compliant segments given similar levels of vaccine confidence. These findings help identify appropriate audiences for campaigns. Results highlight the use of a comprehensive list of attitudes, behaviors, and other individual-level characteristics that can serve as a basis for future segmentation efforts relevant to COVID-19 and other infectious diseases.

What Predicts COVID-Specific Symptoms of Stress in Children and Adolescents, Virus Threats or Social Distancing?

The COVID-19 crisis may have deleterious effects on children's and adolescents' mental health. However, there have been no published studies in which the COVID-related stress symptoms were investigated in a French ordinary pediatric population. The main objective of this study was to examine virus threats and social distancing measures to determine which were more disturbing for children and adolescents, and which were better predictors of post traumatic stress symptoms (PTSS). 1639 parents of children aged between 1 and 18 participated in an online survey. Parents completed questionnaires regarding their children's and adolescents' mental health while in the first French confinement. The data showed that most children and adolescents had PTSS, such as irritability and tantrums, intrusive thoughts or memories, difficulties in falling asleep, aggression, trouble concentrating, and negative emotions. Multiple linear models supported that both virus threats and social distancing- related disturbances were predictors of PTSS scores, with social distancing being a stronger predictor of PTSS scores than virus threats. Additional analyses across age groups revealed that social distancing measures predicted two times more PTSS than virus threat measures in toddlers, while virus threat measures were a stronger predictor of PTSS in adolescents. This is the first study that has investigated stress symptoms in a French pediatric population during the first French confinement episode because of the COVID-19 crisis.

Epidemic control by social distancing and vaccination: Optimal strategies and remarks on the COVID-19 Italian response policy.

After the many failures in the control of the COVID-19 pandemic, identifying robust principles of epidemic control will be key in future preparedness. In this work, we propose an optimal control model of an age-of-infection transmission model under a two-phase control regime where social distancing is the only available control tool in the first phase, while the second phase also benefits from the arrival of vaccines. We analyzed the problem by an ad-hoc numerical algorithm under a strong hypothesis implying a high degree of prioritization to the protection of health from the epidemic attack, which we termed the "low attack rate" hypothesis. The outputs of the model were also compared with the data from the Italian COVID-19 experience to provide a crude assessment of the goodness of the enacted interventions prior to the onset of the Omicron variant.

The power of the family in times of pandemic: Cross-country evidence from 93 countries.

The majority of the hospitalizations and deaths associated with COVID-19 occurred in people over the age of 65. In addition, previous studies have shown that intergenerational contacts played a key role in COVID-19-related infection and fatality. This paper utilized two large-scale multinational surveys to uncover the important role of family ties in infection prevention across 93 countries. Using the World Values Survey, we measured country-level family ties emphasizing respondents' view of their parents. We elicited individual willingness to uptake infection prevention measures from a panel study conducted each month in the early phase of the COVID-19 pandemic between March 2020 and July 2021. We find that in countries with stronger family ties, people show more support for non-pharmaceutical interventions and higher vaccine acceptance; moreover, young people are more supportive of mandatory vaccination. The association between strength of family ties and compliance with infection prevention measures was salient before COVID-19 vaccines became available and was persistent before the global vaccination coverage reached 25%.

Weight gain, new-onset overweight or obesity, and their influencing factors during the social distancing era of the COVID-19 pandemic.

The prevalence of obesity is gradually increasing in South Korea, and the coronavirus disease 2019 (COVID-19) pandemic has accelerated the weight gain. In response to COVID-19, South Korea implemented targeted distancing measures based on the number of COVID-19 cases, rather than a full lockdown. This study focused on two subgroups that influence the rise in obesity prevalence during the early stages of the COVID-19 pandemic and explored the factors contributing to rapid weight gain in this group during this period. This cross-sectional study involved 3,462 participants recruited through the MicroEmbrain Inc. Online survey panel. Participation emails were sent by the research company to the online survey panel, and individuals who voluntarily agreed to participate responded to the survey. The participants consisted of residents aged 19 and above from Seoul, with sample distribution taking considering sex, age, and region. Height, and weight before and during the COVID-19 pandemic were self-reported. The analysis revealed that compared with that of pre-COVID-19 statistics, 11 % of all participants entered the overweight or obese categories post COVID-19, and among those who were overweight or obese before COVID-19, 42.5 % reported weight gain. Both groups had relatively younger individuals, higher stress levels, spent more time alone, and had increased usage of online platforms including online food purchasing. Post-COVID-19 wt gain among individuals with pre-existing overweight or obesity status was associated with a higher frequency of solitary drinking (odds ratio [OR] = 1.407, 95 % confidence interval [CI] = 1.024-1.932), increased online leisure time (OR = 1.336, 95 % CI = 1.063-1.678), and increased use of meal delivery services (OR = 1.307, 95 % CI = 1.026-1.664). The prevalence of obesity has continued to rise after COVID-19 pandemic, highlighting the need for interventions that mitigate the negative impact of the pandemic on health behavior.

Multiple pandemic waves vs multi-period/multi-phasic epidemics: Global shape of the COVID-19 pandemic.

The overall course of the COVID-19 pandemic in Western countries has been characterized by complex sequences of phases. In the period before the arrival of vaccines, these phases were mainly due to the alternation between the strengthening/lifting of social distancing measures, with the aim to balance the protection of health and that of the society as a whole. After the arrival of vaccines, this multi-phasic character was further emphasized by the complicated deployment of vaccination campaigns and the onset of virus' variants. To cope with this multi-phasic character, we propose a theoretical approach to the modeling of overall pandemic courses, that we term multi-period/multi-phasic, based on a specific definition of phase. This allows a unified and parsimonious representation of complex epidemic courses even when vaccination and virus' variants are considered, through sequences of weak ergodic renewal equations that become fully ergodic when appropriate conditions are met. Specific hypotheses on epidemiological and intervention parameters allow reduction to simple models. The framework suggest a simple, theory driven, approach to data explanation that allows an accurate reproduction of the overall course of the COVID-19 epidemic in Italy since its beginning (February 2020) up to omicron onset, confirming the validity of the concept.

Increasing physical activity among adults affected by COVID-19 social distancing restrictions: A feasibility trial of an online intervention.

In response to COVID-19 social distancing restrictions, digitally delivered health interventions present as a potential solution for maintaining or improving individuals' physical activity. This study explored the feasibility of a web-based intervention, informed by the multi-process action control (M-PAC) framework to promote PA among individuals affected by social distancing. Fifty adults self-reporting as insufficiently active were randomized to a 6-week web-intervention (n = 27) or wait-list control (n = 23). Primary feasibility outcomes included recruitment and retention rates and usability and satisfaction scores; secondary outcomes of MVPA and M-PAC constructs and tertiary outcomes of mental health and wellbeing were also assessed. Overall, feasibility of the intervention was high, with a 96% recruitment rate, 84% retention rate, high satisfaction and usability scores, and comparable website usage to similar eHealth interventions. Intervention participants trended towards improved MVPA and M-PAC constructs and outcomes of mental health and wellbeing. Findings suggest study extension to a full-scale RCT.

Polarization and health-related behaviours and outcomes during the COVID-19 pandemic: a systematic review protocol.

Introduction: The COVID-19 pandemic affected people's health behaviours and health outcomes. Political or affective polarization could be associated with health behaviours such as mask-wearing or vaccine uptake and with health outcomes, e.g., infection or mortality rate. Political polarization relates to divergence or spread of ideological beliefs and affective polarization is about dislike between people of different political groups, such as ideologies or parties. The objectives of this study are to investigate and synthesize evidence about associations between both forms of polarization and COVID-19 health behaviours and outcomes. Methods: In this systematic review, we will include quantitative studies that assess the relationship between political or affective polarization and COVID-19-related behaviours and outcomes, including adherence to mask mandates, vaccine uptake, infection and mortality rate. We will use a predetermined strategy to search EMBASE, Medline (Ovid), Cochrane Library, Cochrane COVID-19 Study Register, Global Health (Ovid), PsycInfo (Ovid), Web of Science, CINAHL, EconLit (EBSCOhost), WHO COVID-19 Database, iSearch COVID-19 Portfolio (NIH) and Google Scholar from 2019 to September 8 2023. One reviewer will screen unique records according to eligibility criteria. A second reviewer will verify the selection. Data extraction, using pre-piloted electronic forms, will follow a similar process. The risk of bias of the included studies will be assessed using the JBI checklist for analytical cross sectional studies. We will summarise the included studies descriptively and examine the heterogeneity between studies. Quantitative data pooling might not be feasible due to variations in measurement methods used to evaluate exposure, affective and political polarization. If there are enough relevant studies for statistical data synthesis, we will conduct a meta-analysis. Discussion: This review will help to better understand the concept of polarization in the context of the COVID-19 pandemic and might inform decision making for future pandemics. Protocol registration: PROSPERO ID: CRD42023475828.

Mental well-being of children and adolescents during COVID-19: evidence from the Italian context and possible future developments.

The article aims to discuss the increased emergence of mental health problems among children and adolescents, as an outcome of the COVID-19 pandemic.The results of a research study conducted among various professionals, such as psychiatrists and psychologists specialized in childhood and adolescence, are presented. The study, which uses both qualitative and quantitative methods, investigates the main consequences of the physical social distancing measures undertaken by the Italian government during the pandemic. The results are in line with the main evidence highlighted by international research and underline the particularly negative effects of the pandemic emergency on the mental health of minors. It reports how the limitation of intersubjective relationships and the forced digitalization of relationships has triggered or caused the emergence of multiple and varied disorders of the psyche, also linked to the area of reference (e.g., metropolitan, urban o remote areas), the socio-economic and cultural fragility of families, as well as the presence of previous mental issues within them. Finally, the research emphasizes how the understanding and management of the psychic health of these population groups, also from a health organization point of view, will be crucial to address the medium and long-term effects of such emerging issues among younger cohorts.

COVID-19 Public Health Restrictions and New Mothers' Mental Health: A Qualitative Scoping Review.

Public health restrictions to protect physical health during the COVID-19 pandemic had unintended effects on mental health, which may have disproportionately affected some potentially vulnerable groups. This scoping review of qualitative research provides a narrative synthesis of new mothers' perspectives on their mental health during COVID-19 pandemic restrictions through pregnancy to the postpartum period. Database searches in PubMed, CINAHL, and PsycINFO sought primary research studies published until February 2023, which focused on new mothers' self-perceived mental health during the pandemic (N = 55). Our synthesis found that new mothers' mental health was impacted by general public health restrictions resulting in isolation from family and friends, a lack of community support, and impacts on the immediate family. However, public health restrictions specific to maternal and infant healthcare were most often found to negatively impact maternal mental health, namely, hospital policies prohibiting the presence of birthing partners and in-person care for their infants. This review of qualitative research adds depth to previous reviews that have solely examined the quantitative associations between COVID-19 public health restrictions and new mothers' mental health. Here, our review demonstrates the array of adverse impacts of COVID-19 public health restrictions on new mothers' mental health throughout pregnancy into the postpartum period, as reported by new mothers. These findings may be beneficial for policy makers in future public health emergency planning when evaluating the impacts and unintended consequences of public health restrictions on new mothers.

Role of information sources in adherence to COVID-19-related safety measures among college students in the USA.

OBJECTIVE: During the COVID-19 pandemic, information sources such as public officials, national/international media, social media, public health agencies, college/university officials, etc., played a vital role in adherence to safety measures, including hygiene practices, social distancing, and mask-wearing. We analyze the role of trusted sources of information in adherence to safety measures and explore potential disparities among US college students during the pandemic. METHODS: We analyze Healthy Minds Study (HMS) 2020-2021 COVID Module data and utilize multivariable logistic regressions controlling for sociodemographic and COVID-19-related factors. Subgroup analyses were conducted by gender, citizenship status, race, and educational level. RESULTS: Significant differences were found in adherence to safety measures when information was received from different sources. Demographic subgroups within the college student population depended on different sources of COVID-19-related information. Adherence to COVID-19-related safety measures also differed by demographic characteristics. CONCLUSION: This analysis supports the necessity for targeted health-related messaging among US college students.

Public transit mobility as a leading indicator of COVID-19 transmission in 40 cities during the first wave of the pandemic.

Background: The rapid global emergence of the COVID-19 pandemic in early 2020 created urgent demand for leading indicators to track the spread of the virus and assess the consequences of public health measures designed to limit transmission. Public transit mobility, which has been shown to be responsive to previous societal disruptions such as disease outbreaks and terrorist attacks, emerged as an early candidate. Methods: We conducted a longitudinal ecological study of the association between public transit mobility reductions and COVID-19 transmission using publicly available data from a public transit app in 40 global cities from March 16 to April 12, 2020. Multilevel linear regression models were used to estimate the association between COVID-19 transmission and the value of the mobility index 2 weeks prior using two different outcome measures: weekly case ratio and effective reproduction number. Results: Over the course of March 2020, median public transit mobility, measured by the volume of trips planned in the app, dropped from 100% (first quartile (Q1)-third quartile (Q3) = 94-108%) of typical usage to 10% (Q1-Q3 = 6-15%). Mobility was strongly associated with COVID-19 transmission 2 weeks later: a 10% decline in mobility was associated with a 12.3% decrease in the weekly case ratio (exp(ß) = 0.877; 95% confidence interval (CI): [0.859-0.896]) and a decrease in the effective reproduction number (ß = -0.058; 95% CI: [-0.068 to -0.048]). The mobility-only models explained nearly 60% of variance in the data for both outcomes. The adjustment for epidemic timing attenuated the associations between mobility and subsequent COVID-19 transmission but only slightly increased the variance explained by the models. Discussion: Our analysis demonstrated the value of public transit mobility as a leading indicator of COVID-19 transmission during the first wave of the pandemic in 40 global cities, at a time when few such indicators were available. Factors such as persistently depressed demand for public transit since the onset of the pandemic limit the ongoing utility of a mobility index based on public transit usage. This study illustrates an innovative use of "big data" from industry to inform the response to a global pandemic, providing support for future collaborations aimed at important public health challenges.

SIR+ models: accounting for interaction-dependent disease susceptibility in the planning of public health interventions.

Avoiding physical contact is regarded as one of the safest and most advisable strategies to follow to reduce pathogen spread. The flip side of this approach is that a lack of social interactions may negatively affect other dimensions of health, like induction of immunosuppressive anxiety and depression or preventing interactions of importance with a diversity of microbes, which may be necessary to train our immune system or to maintain its normal levels of activity. These may in turn negatively affect a population's susceptibility to infection and the incidence of severe disease. We suggest that future pandemic modelling may benefit from relying on 'SIR+ models': epidemiological models extended to account for the benefits of social interactions that affect immune resilience. We develop an SIR+ model and discuss which specific interventions may be more effective in balancing the trade-off between minimizing pathogen spread and maximizing other interaction-dependent health benefits. Our SIR+ model reflects the idea that health is not just the mere absence of disease, but rather a state of physical, mental and social well-being that can also be dependent on the same social connections that allow pathogen spread, and the modelling of public health interventions for future pandemics should account for this multidimensionality.

Social distancing during the COVID-19 pandemic: Potential impact and correlation with asthma.

BACKGROUND: Non-pharmaceutical interventions have been implemented globally to control the COVID-19 pandemic and have been shown to alleviate both allergies and respiratory infections. Although mask-wearing is an accepted non-pharmaceutical intervention, the effects of social distancing have not been thoroughly evaluated. OBJECTIVES: To evaluate the effects of social distancing on asthma trends in Seoul, South Korea. METHODS: This study included data from the National Health Insurance Service of South Korea, covering approximately 10 million people in Seoul. Daily and monthly data of patients with asthma from 2018 to 2021 were examined, and the degree of social distancing performance was measured using the number of subway users as an index. Pearson's correlation coefficient was used to determine the relationship between the two indices. The change-point detection technique, cross-correlation, and Granger causality method were used to assess the temporal causality between social distancing and asthma. RESULTS: The number of patients with asthma decreased by 42.4 % from 2019 to 2020, while that of subway users decreased by 26.3 % during this period. Pearson's correlation analysis revealed significant positive correlations. Asthma and subway users showed a significant change in incidence following the implementation of social distancing; subway users showed a causal relationship with patients with asthma. CONCLUSION: Our results showed that the number of subway users decreased after the implementation of strict social distancing, coinciding with a decrease in the number of patients with asthma. These findings suggest that social distancing measures implemented to control COVID-19 may reduce the incidence and exacerbation of asthma.

Mediation Effect of Social Distancing on Neonatal Vitamin D Status and Related Clinical Outcomes during the Coronavirus Disease-19 Pandemic.

BACKGROUND: We analyzed the impact of social distancing (SD) on vitamin D status and associated morbidity in neonates during the coronavirus disease (COVID-19) pandemic. METHODS: Serum levels of 25-hydroxy vitamin D (25OHD) and clinical characteristics of newborn infants before (2019) and during SD (2021) were compared. RESULTS: A total of 526 neonates (263 in 2019 and 263 in 2021) were included. The rate of vitamin D deficiency in neonates (47.1% vs. 35.4 %, p = 0.008) decreased and the rate of maternal vitamin D intake increased (6.8% vs. 37.6%, p < 0.001), respectively, during SD compared to those in 2019. The rates of hypocalcemia (12.5% vs. 3.8%, p < 0.001) and respiratory illness (57.0% vs. 43.0%, p = 0.002) decreased during SD. Neonatal vitamin D deficiency during SD was associated with maternal vitamin D supplementation (odds ratio [OR] = 0.463, p = 0.003) but was not associated with SD (OR = 0.772, p = 0.189). The mediation effect of SD on neonatal morbidity by neonatal vitamin D status was statistically insignificant. CONCLUSIONS: SD might affect the increased maternal vitamin D intake and decreased neonatal vitamin D deficiency. However, neonatal morbidity was not affected by SD, even with neonatal vitamin D status changes.

Transmission Patterns of Co-Circulation of Omicron Sub-Lineages in Hong Kong SAR, China, a City with Rigorous Social Distancing Measures, in 2022.

OBJECTIVE: This study aimed to characterize the changing landscape of circulating SARS-CoV-2 lineages in the local community of Hong Kong throughout 2022. We examined how adjustments to quarantine arrangements influenced the transmission pattern of Omicron variants in a city with relatively rigorous social distancing measures at that time. METHODS: In 2022, a total of 4684 local SARS-CoV-2 genomes were sequenced using the Oxford Nanopore GridION sequencer. SARS-CoV-2 consensus genomes were generated by MAFFT, and the maximum likelihood phylogeny of these genomes was determined using IQ-TREE. The dynamic changes in lineages were depicted in a time tree created by Nextstrain. Statistical analysis was conducted to assess the correlation between changes in the number of lineages and adjustments to quarantine arrangements. RESULTS: By the end of 2022, a total of 83 SARS-CoV-2 lineages were identified in the community. The increase in the number of new lineages was significantly associated with the relaxation of quarantine arrangements (One-way ANOVA, F(5, 47) = 18.233, p < 0.001)). Over time, Omicron BA.5 sub-lineages replaced BA.2.2 and became the predominant Omicron variants in Hong Kong. The influx of new lineages reshaped the dynamics of Omicron variants in the community without fluctuating the death rate and hospitalization rate (One-way ANOVA, F(5, 47) = 2.037, p = 0.091). CONCLUSION: This study revealed that even with an extended mandatory quarantine period for incoming travelers, it may not be feasible to completely prevent the introduction and subsequent community spread of highly contagious Omicron variants. Ongoing molecular surveillance of COVID-19 remains essential to monitor the emergence of new recombinant variants.

Population Behavior Changes Underlying Phasic Shifts of SARS-CoV-2 Exposure Settings Across 3 Omicron Epidemic Waves in Hong Kong: Prospective Cohort Study.

BACKGROUND: Exposure risk was shown to have affected individual susceptibility and the epidemic spread of COVID-19. The dynamics of risk by and across exposure settings alongside the variations following the implementation of social distancing interventions are understudied. OBJECTIVE: This study aims to examine the population's trajectory of exposure risk in different settings and its association with SARS-CoV-2 infection across 3 consecutive Omicron epidemic waves in Hong Kong. METHODS: From March to June 2022, invitation letters were posted to 41,132 randomly selected residential addresses for the recruitment of households into a prospective population cohort. Through web-based monthly surveys coupled with email reminders, a representative from each enrolled household self-reported incidents of SARS-CoV-2 infections, COVID-19 vaccination uptake, their activity pattern in the workplace, and daily and social settings in the preceding month. As a proxy of their exposure risk, the reported activity trend in each setting was differentiated into trajectories based on latent class growth analyses. The associations of different trajectories of SARS-CoV-2 infection overall and by Omicron wave (wave 1: February-April; wave 2: May-September; wave 3: October-December) in 2022 were evaluated by using Cox proportional hazards models and Kaplan-Meier analysis. RESULTS: In total, 33,501 monthly responses in the observation period of February-December 2022 were collected from 5321 individuals, with 41.7% (2221/5321) being male and a median age of 46 (IQR 34-57) years. Against an expanding COVID-19 vaccination coverage from 81.9% to 95.9% for 2 doses and 20% to 77.7% for 3 doses, the cumulative incidence of SARS-CoV-2 infection escalated from <0.2% to 25.3%, 32.4%, and 43.8% by the end of waves 1, 2, and 3, respectively. Throughout February-December 2022, 52.2% (647/1240) of participants had worked regularly on-site, 28.7% (356/1240) worked remotely, and 19.1% (237/1240) showed an assorted pattern. For daily and social settings, 4 and 5 trajectories were identified, respectively, with 11.5% (142/1240) and 14.6% (181/1240) of the participants gauged to have a high exposure risk. Compared to remote working, working regularly on-site (adjusted hazard ratio [aHR] 1.47, 95% CI 1.19-1.80) and living in a larger household (aHR 1.12, 95% CI 1.06-1.18) were associated with a higher risk of SARS-CoV-2 infection in wave 1. Those from the highest daily exposure risk trajectory (aHR 1.46, 95% CI 1.07-2.00) and the second highest social exposure risk trajectory (aHR 1.52, 95% CI 1.18-1.97) were also at an increased risk of infection in waves 2 and 3, respectively, relative to the lowest risk trajectory. CONCLUSIONS: In an infection-naive population, SARS-CoV-2 transmission was predominantly initiated at the workplace, accelerated in the household, and perpetuated in the daily and social environments, as stringent restrictions were scaled down. These patterns highlight the phasic shift of exposure settings, which is important for informing the effective calibration of targeted social distancing measures as an alternative to lockdown.