Anticipation of COVID-19 vaccines reduces willingness to socially distance

Looking beyond vaccines: Cultural tightness-looseness moderates the relationship between immunization coverage and disease prevention vigilance

Advancements in vaccination technologies mitigate disease transmission risks but may inadvertently suppress the behavioral immune system, an evolved disease avoidance mechanism. Applying behavioral immune system theory and utilizing robust big data analytics, we examined associations between rising vaccination coverage and government policies, public mobility, and online information seeking regarding disease precautions. We tested whether cultural tightness-looseness moderates the relationship between mass immunization and disease prevention vigilance. Comprehensive time series analyses were conducted using American data (Study 1) and international data (Study 2), employing transfer function modeling, cross-correlation function analysis, and meta-regression analysis. Across both the US and global analyses, as vaccination rates rose over time, government COVID-19 restrictions significantly relaxed, community mobility increased, and online searches for prevention information declined. The relationship between higher vaccination rates and lower disease prevention vigilance was stronger in culturally looser contexts. Results provide initial evidence that mass immunization may be associated with attenuated sensitivity and enhanced flexibility of disease avoidance psychology and actions. However, cultural tightness-looseness significantly moderates this relationship, with tighter cultures displaying sustained vigilance amidst immunization upticks. These findings offer valuable perspectives to inform nuanced policymaking and public health strategies that balance prudent precautions against undue alarm when expanding vaccine coverage worldwide.

Compliance in the public versus the private realm: Economic preferences, institutional trust and COVID-19 health behaviors

To what extent do economic preferences and institutional trust predict compliance with physical distancing rules during the COVID-19 pandemic? We reexamine this question by introducing the theoretical and empirical distinction between individual health behaviors in the public and in the private domain (e.g., keeping a distance from strangers vs. abstaining from private gatherings with friends). Using structural equation modeling to analyze survey data from Germany's second wave of the pandemic (N = 3350), we reveal the following major differences between compliance in both domains: Social preferences, especially (positive) reciprocity, play an essential role in predicting compliance in the public domain but are barely relevant in the private domain. Conversely, individuals' degree of trust in the national government matters predominantly for increasing compliance in the private domain. The clearly strongest predictor in this domain is the perception pandemic-related threats. Our findings encourage tailoring communication strategies to either domain-specific circumstances or factors common across domains. Tailored communication may also help promote compliance with other health-related regulatory policies beyond COVID-19.

A Preference-Based Value Assessment of the Fear of COVID-19 Contagion

Purpose

To assess the preference-based value of the fear of COVID-19 contagion.

Patients and Methods

We conducted a web-based, cross-sectional discrete choice experiment among 544 US adults. We used a Bayesian efficient design to generate choice sets. Each choice set comprised two hypothetical COVID-19 vaccine options characterized by seven attributes: chance of COVID-19 infection, chance of having severe symptoms from COVID-19 infection, vaccine protection duration, chance of mild to moderate adverse events from vaccination, chance of serious adverse events from vaccination, chance of future exposure to COVID-19 after vaccination, and out-of-pocket cost. We used mixed logit (ML) and latent class (LC) models to analyze data. Furthermore, we calculated the willingness-to-pay for eliminating the chance of future exposure to COVID-19, shedding light on the value attributed to the fear of contagion.

Results

The ML model demonstrated all attributes, including the chance of future exposure to COVID-19, were statistically significant. The participants were willing to pay approximately $13,046 to eliminate the chance of future exposure to COVID-19 or their fear of contagion when COVID-19 was still pandemic. The LC model unveiled two participant classes with distinct preference weights for the chance of future exposure to COVID-19 and out-of-pocket cost attributes. Nevertheless, the chance of future exposure to COVID-19 exposure held a significant degree of importance in both classes.

Conclusion

The chance of future exposure to COVID-19 exposure or fear of contagion was a significant element in the value assessment of COVID-19 vaccines. Further studies should be conducted to verify the value of fear of contagion and include it in the value assessment of healthcare technologies for infectious diseases.

Assessing the risk of COVID-19 reinfection and severe outcomes among individuals with substance use disorders: a retrospective study using real-world electronic health records

OBJECTIVE

Despite advancement in vaccines and treatments for COVID-19 over the past 2 years, many concerns remain about reinfection and waning immunity against COVID-19 and its variants, especially among people with substance use disorder (SUD). The study assessed the risk of COVID-19 reinfection and severe illness among adults with SUD and their vaccination status to inform management in this vulnerable population as the pandemic continues.

DESIGN

Retrospective cohort study.

SETTING

Nationwide electronic health records (TriNetX database) in the USA among adults with COVID-19 infection from January 2020 to June 2022.

PARTICIPANTS

Adults (age ≥18 years) who were infected by COVID-19, excluding those who had cancer or lived in nursing homes or palliative care facilities.

OUTCOME MEASURES

COVID-19 reinfection was defined as a new diagnosis after 45 days of the initial infection. Logistic regression was applied to assess the OR of COVID-19 reinfection and severe outcomes within 30 day of reinfection for adults with alcohol (AUD), opioid (OUD), cocaine (CUD), stimulant (STUD), cannabis (CAUD) and other use disorders, controlled for demographic and comorbid conditions.

RESULTS

The SUD cohort was 13%-29% more likely to be reinfected by COVID-19 and had significantly higher 30-day mortality. Adults with AUD, STUD and OUD were at greater risks (adjusted ORs, AORs=1.69-1.86) of emergency department, hospital and intensive care admissions after 30 days of reinfection. Individuals with SUD and multiple vaccines doses were associated with decreased risks of worse COVID-19 outcomes. Lower COVID-19 reinfection rates (AORs=0.67-0.84) were only found among individuals with AUD, CUD or CAUD who had COVID-19 vaccination.

CONCLUSIONS

Individuals with SUD had greater risks of COVID-19 reinfection and poor outcomes, especially those with OUD, STUD and AUD. Multiple vaccinations are recommended to reduce severe illness after COVID-19 reinfection in the SUD population.

Consequences of a shortage and rationing: Evidence from a pediatric vaccine

Shortages and rationing are common in health care, yet we know little about the consequences. We examine an 18-month shortage of the pediatric Haemophilus Influenzae Type B (Hib) vaccine. Using insurance claims data and variation in shortage exposure across birth cohorts, we find that the shortage reduced uptake of high-value primary doses by 4 percentage points and low-value booster doses by 26 percentage points. This suggests providers largely complied with rationing recommendations. In the long-run, catch-up vaccination occurred but was incomplete: shortage-exposed cohorts were 4 percentage points less likely to have received the ir booster dose years later. We also find that the shortage and rationing caused provider switches, extra provider visits, and negative spillovers to other care.

Behavioral Changes Associated With COVID-19 Vaccination: Cross-National Online Survey

BACKGROUND

During the initial phases of the vaccination campaign worldwide, nonpharmaceutical interventions (NPIs) remained pivotal in the fight against the COVID-19 pandemic. In this context, it is important to understand how the arrival of vaccines affected the adoption of NPIs. Indeed, some individuals might have seen the start of mass vaccination campaigns as the end of the emergency and, as a result, relaxed their COVID-safe behaviors, facilitating the spread of the virus in a delicate epidemic phase such as the initial rollout.

OBJECTIVE

The aim of this study was to collect information about the possible relaxation of protective behaviors following key events of the vaccination campaign in four countries and to analyze possible associations of these behavioral tendencies with the sociodemographic characteristics of participants.

METHODS

We developed an online survey named "COVID-19 Prevention and Behavior Survey" that was conducted between November 26 and December 22, 2021. Participants were recruited using targeted ads on Facebook in four different countries: Brazil, Italy, South Africa, and the United Kingdom. We measured the onset of relaxation of protective measures in response to key events of the vaccination campaign, namely personal vaccination and vaccination of the most vulnerable population. Through calculation of odds ratios (ORs) and regression analysis, we assessed the strength of association between compliance with NPIs and sociodemographic characteristics of participants.

RESULTS

We received 2263 questionnaires from the four countries. Participants reported the most significant changes in social activities such as going to a restaurant or the cinema and visiting relatives and friends. This is in good agreement with validated psychological models of health-related behavioral change such as the Health Belief Model, according to which activities with higher costs and perceived barriers (eg, social activities) are more prone to early relaxation. Multivariate analysis using a generalized linear model showed that the two main determinants of the drop of social NPIs were (1) having previously tested positive for COVID-19 (after the second vaccine dose: OR 2.46, 95% CI 1.73-3.49) and (2) living with people at risk (after the second vaccine dose: OR 1.57, 95% CI 1.22-2.03).

CONCLUSIONS

This work shows that particular caution has to be taken during vaccination campaigns. Indeed, people might relax their safe behaviors regardless of the dynamics of the epidemic. For this reason, it is crucial to maintain high compliance with NPIs to avoid hindering the beneficial effects of the vaccine.

Are Fear Campaigns Effective for Increasing Adherence to COVID-Related Mitigation Measures?

BACKGROUND

Using fear to increase the uptake of preventative health behaviours is a longstanding practice, which could be useful in mitigating the spread of COVID-19. However, the impact of fear campaigns beyond behavioural outcomes has rarely been considered. It is possible that these threatening health messages could heighten health-related anxiety by inducing a tendency to interpret ambiguous stimuli in a threatening manner. This research aimed to evaluate the effects of fear-based articles about COVID-19, on intentions to adhere to mitigation measures and interpretation bias-a core maintenance factor in health anxiety.

METHOD

Two pilot studies were conducted with the aim of validating our novel COVID-related measures and assessing engagement with the threat manipulation. Following this, 375 community members were recruited through social media for the main study. Participants were then randomly allocated to read an article about COVID which was manipulated on both threat and efficacy. After reading the article, participants then completed measures of interpretation bias and intentions to engage in COVID-19 mitigation measures.

RESULTS

Although the threatening articles consistently produced greater COVID-related threat, they only generated a stronger interpretation bias in the first pilot study. Importantly, threat-based communications failed to enhance intentions to perform mitigation measures in any of the studies. Likewise, reading an article which bolstered self-efficacy did not increase intentions, compared to reading a low efficacy article.

CONCLUSION

This research suggests that fear appeals are unlikely to increase intentions to perform COVID-related mitigation measures.

Effect of SARS-CoV-2 prior infection and mRNA vaccination on contagiousness and susceptibility to infection

The immunity conferred by SARS-CoV-2 vaccines and infections reduces the transmission of the virus. To answer how the effect of immunity is shared between a reduction of infectiousness and an increased protection against infection, we examined >50,000 positive cases and >110,000 contacts from Geneva, Switzerland (June 2020 to March 2022). We assessed the association between secondary attack rate (i.e. proportion of new cases among contacts) and immunity from natural infection and/or vaccination, stratifying per four SARS-CoV-2 variants and adjusting for index cases and contacts' socio-demographic characteristics and the propensity of the contacts to be tested. Here we show that immunity protected contacts from infection, rather than reducing infectiousness of index cases. Natural infection conferred the strongest immunity. Hybrid immunity did not surpass recent infection. Although of smaller amplitude, the reduction in infectiousness due to vaccination was less affected by time and by the emergence of new SARS-CoV-2 variants than the susceptibility to infection. These findings support the role of vaccine in reducing infectiousness and underscore the complementary role of interventions reducing SARS-CoV-2 propagation, such as mask use or indoor ventilation.

Social participation during the COVID-19 pandemic in persons with a high risk for a severe course of COVID-19 - results of a longitudinal, multi-center observational study in Germany

Objective

The COVID-19 pandemic has affected how people go about their daily lives, often in various and substantial ways. This study aims to prospectively evaluate the changes in social participation during the COVID-19 pandemic in persons with a high risk for a severe COVID-19 course in Germany.

Methods

A paper-pencil-based survey was conducted starting at March 2021. Participants filled out questionnaires at four time points based on their COVID-19 vaccination status: before COVID-19 vaccination, one month, six months and twelve months after COVID-19 vaccination. Social participation measures included the Pandemic Social Participation Questionnaire (PSP-Q) and the Index for measuring participation restrictions (IMET). Repeated measures ANOVA and paired t-test were used to test for changes between time-points. Repeated measures correlation was used to assess the relationship between social participation and local COVID-19 incidences.

Results

Data from 245 participants was analyzed before and one month after COVID-19 vaccination. In addition, data from 156 participants was analyzed at time points one, six and twelve months after COVID-19. PSP-Q and IMET scores changed significantly after participants received a COVID-19 vaccination. Between one month and twelve months after vaccination, social participation improved significantly measured by PSP-Q. Social participation was negatively correlated with regional COVID-19 incidences before and after COVID-19 vaccination. Social participation was positively correlated with COVID-19 incidences between one month and twelve months after COVID-19 vaccination.

Conclusions

Social participation improved in persons with a high risk for a severe COVID-19 course during the pandemic. The local COVID-19 incidence showed a negative association with social participation only until the fall of 2021 when it was used as the sole metric to regulate COVID-19 protective measures. Although our data describes the trends in social participation, further studies are needed to identify the influencing factors for the observed increase in social participation.

Household secondary attack rates and risk factors during periods of SARS-CoV-2 Delta and Omicron variant predominance in the Republic of Korea

BACKGROUND

The household secondary attack rate (SAR) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important indicator for community transmission. This study aimed to characterize transmission by comparing household SARs and identifying risk factors during the periods of Delta and Omicron variant predominance in Republic of Korea.

METHODS

We defined the period of Delta variant predominance (Delta period) as July 25, 2021 to January 15, 2022, and the period of Omicron variant predominance (Omicron period) as February 7 to September 3, 2022. The number of index cases included was 214,229 for the Delta period and 5,521,393 for the Omicron period. To identify the household SARs and risk factors for each period, logistic regression was performed to determine the adjusted odds ratio (aOR).

RESULTS

The SAR was 35.2% for the Delta period and 43.1% for the Omicron period. The aOR of infection was higher in 2 groups, those aged 0 to 18 years and ≥75 years, compared to those aged 19 to 49 years. Unvaccinated individuals (vs. vaccinated individuals) and individuals experiencing initial infection (vs. individuals experiencing a second or third infection) had an increased risk of infection with SARS-CoV-2.

CONCLUSION

This study analyzed the household SARs and risk factors. We hope that the results can help develop age-specific immunization plans and responses to reduce the SAR in preparation for emerging infectious diseases or potential new variants of SARS-CoV-2.

The politicized pandemic: Ideological polarization and the behavioral response to COVID-19

In a representative sample of the U.S. population during the first summer of the COVID-19 pandemic, we investigate how prosociality and ideology interact in their relationship with health-protecting behavior and trust in the government to handle the crisis. We find that an experimental measure of prosociality based on standard economic games positively relates to protective behavior. Conservatives are less compliant with COVID-19-related behavioral restrictions than liberals and evaluate the government's handling of the crisis significantly more positively. We show that prosociality does not mediate the impact of political ideology. This finding means that conservatives are less compliant with protective health guidelines - independent of differences in prosociality between both ideological camps. Behavioral differences between liberals and conservatives are roughly only one-fourth of the size of their differences in judging the government's crisis management. This result suggests that Americans were more polarized in their political views than in their acceptance of public health advice.

Double Jab: Survey Evidence on Vaccine Hesitancy, Beliefs, and Attitudes in India

India witnessed a large surge in COVID-19 cases in April 2021, a second wave of nearly 350,000 daily new infections across the country. As of December 2021, cases have reduced drastically, in part due to greater vaccine coverage across the country. This study reports results on vaccine hesitancy, attitudes, and behaviors from an online survey conducted between February and March 2021 in nine Indian cities (N = 518). We find that vaccine hesitancy negatively predicts willingness to take the vaccine, and beliefs about vaccine effectiveness supersede hesitancy in explaining vaccine uptake. Furthermore, we find that mask-wearing and handwashing beliefs, information sources related to COVID-19, and past COVID-19 infection and testing status are all strongly associated with the hypothetical choice of vaccine. We discuss these findings in the context of behavioral theories as well as outline implications for vaccine-related health communication in India.

Family size and vaccination among older individuals: The case of COVID-19 vaccine

While vaccination is generally considered efficient in protecting against transmissible diseases, the compliance is not complete in many countries. In this study, we investigate how an individual-specific factor - family size - affects the probability of getting vaccinated against COVID-19. To answer this research question, we focus on individuals above 50 years of age, who are at a higher risk of developing severe symptoms. The analysis uses the Survey of Health, Ageing and Retirement in Europe Corona wave, conducted in the summer of 2021. To identify the effect of family size on vaccination, we exploit an exogenous variation in the probability of having more than two children, due to the sex composition of two firstborns. We document that a larger family size increases the probability of receiving the COVID-19 vaccine among older individuals. This impact is economically and statistically significant. We propose several potential mechanisms behind this result and document that family size can be related to the higher probability of being exposed to the disease. This effect can be by knowing someone who tested positive for COVID-19 or had symptoms similar to it, and by network size and frequency of contact with children, before the outbreak of COVID-19.

Built environment factors moderate pandemic fatigue in social distance during the COVID-19 pandemic: A nationwide longitudinal study in the United States

Non-pharmaceutical interventions (NPIs) remain some of the most effective measures for coping with the ever-changing coronavirus disease 2019 (COVID-19) pandemic. Pandemic fatigue, which manifests as the declined willingness to follow the recommended protective behaviors (e.g., keeping social distance policies, wearing masks), has commanded increasing attention from researchers and policymakers after the prolonged NPIs and COVID-19 worldwide. However, long-term changes in pandemic fatigue are not well understood, especially amidst the ever-changing pandemic landscape. Built environment factors have been shown to positively affect mental and physical health, but it is still unclear whether built environments can moderate pandemic fatigue. In this study, we used Google mobility data to investigate longitudinal trends of pandemic fatigue in social distance since the onset of NPIs enforcement in the United States. The results indicated that pandemic fatigue continuously worsened over nearly two years of NPIs implementation, and a sharp increase occurred after the vaccination program began. Additionally, we detected a significant moderation effect of greenspace and urbanicity levels on pandemic fatigue. People living in areas with high levels of greenness or urbanicity experienced lower levels of pandemic fatigue. These findings not only shed new light on the effects of greenness and urbanicity on COVID-19 pandemic fatigue, but also provide evidence for developing more tailored and effective strategies to cope with pandemic fatigue.

School-age vaccination, school openings and Covid-19 diffusion

This article investigates the relationship between school openings and Covid-19 diffusion when school-age vaccination becomes available. The analysis relies on a unique geo-referenced high frequency database on age of vaccination, Covid-19 cases and hospitalization indicators from the Italian region of Sicily. The study focuses on the change of Covid-19 diffusion after school opening in a homogeneous geographical territory (i.e., with the same control measures and surveillance systems, centrally coordinated by the Regional Government). The identification of causal effects derives from a comparison of the change in cases before and after school opening in the school year 2020/21, when vaccination was not available, and in 2021/22, when the vaccination campaign targeted individuals of age 12-19 and above 19. Results indicate that, while school opening determined an increase in the growth rate of Covid-19 cases in 2020/2021, this effect has been substantially reduced by school-age vaccination in 2021/2022. In particular, we find that an increase of approximately 10% in the vaccination rate of school-age population reduces the growth rate of Covid-19 cases after school opening by approximately 1%.

Impact of policy response on health protection and economic recovery in OECD and BRIICS countries during the early stages of the COVID-19 pandemic

OBJECTIVES

During the early stages of the COVID-19 pandemic, the full reopening of the economy typically accelerated viral transmission. This study aims to determine whether policy response could contribute to the dual objective of both reducing the spread of the epidemic and revitalising economic activities.

STUDY DESIGN

This is a longitudinal study of Organization for Economic Cooperation and Development (OECD) and Brazil, Russia, India, Indonesia, China, and South Africa (BRIICS) from the first quarter (Q1) of 2020 to the same period of 2021.

METHODS

From a health-economic perspective, this study established a framework to illustrate the following outcomes: suppression-prosperity, outbreak-stagnancy, outbreak-prosperity and suppression-stagnancy scenarios. Multinomial logistic models were used to analyse the associations between policy response with both the pandemic and the economy. The study further examined two subtypes of policy response, stringency/health measures and economic support measures, separately. The probabilities of the different scenarios were estimated.

RESULTS

Economic prosperity and epidemic suppression were significantly associated with policy response. The effects of policy response on health-economic scenarios took the form of inverse U-shapes with the increase in intensity. 'Leptokurtic', 'bimodal' and 'long-tailed' curves demonstrated the estimated possibilities of suppression-prosperity, outbreak-prosperity and suppression-stagnancy scenarios, respectively. In addition, stringency/health policies followed the inverted U-shaped pattern, whereas economic support policies showed a linear pattern.

CONCLUSIONS

It was possible to achieve the dual objective of economic growth and epidemic control simultaneously, and the effects of policy response were shaped like an inverse U. These findings provide a new perspective for balancing the economy with public health during the early stages of the pandemic.

Determinants of people's motivations to approach COVID-19 vaccination centers

This paper presents the results of a survey exploring the determinants of vacinees' confidence in COVID-19 vaccines and their motivations to become vaccinated. At the threatening rise of the highly infectious Omicron variant, in December 2021, we interviewed people in waiting lines of vaccination centers. Our results identify risk-averse and social-distancing-compliant people as showing high confidence in the vaccine, which motivates them to receive it for reasons of protecting themselves and others. By contrast, policy incentives, such as "3G/2G" restrictions, motivate risk-tolerant people who opted for vaccination to get access to public areas. Trusting people who regularly vote are little afraid of vaccines' side effects. Our findings offer insights for policymakers in societies and firms that help to tailor policies promoting vaccination based on people's economic preferences.

Financial incentives for vaccination do not have negative unintended consequences

Financial incentives to encourage healthy and prosocial behaviours often trigger initial behavioural change1-11, but a large academic literature warns against using them12-16. Critics warn that financial incentives can crowd out prosocial motivations and reduce perceived safety and trust, thereby reducing healthy behaviours when no payments are offered and eroding morals more generally17-24. Here we report findings from a large-scale, pre-registered study in Sweden that causally measures the unintended consequences of offering financial incentives for taking the first dose of a COVID-19 vaccine. We use a unique combination of random exposure to financial incentives, population-wide administrative vaccination records and rich survey data. We find no negative consequences of financial incentives; we can reject even small negative impacts of offering financial incentives on future vaccination uptake, morals, trust and perceived safety. In a complementary study, we find that informing US residents about the existence of state incentive programmes also has no negative consequences. Our findings inform not only the academic debate on financial incentives for behaviour change but also policy-makers who consider using financial incentives to change behaviour.

Using a real-world network to model the trade-off between stay-at-home restriction, vaccination, social distancing and working hours on COVID-19 dynamics

Background

Human behaviour, economic activity, vaccination, and social distancing are inseparably entangled in epidemic management. This study aims to investigate the effects of various parameters such as stay-at-home restrictions, work hours, vaccination, and social distance on the containment of pandemics such as COVID-19.

Methods

To achieve this, we have developed an agent based model based on a time-dynamic graph with stochastic transmission events. The graph is constructed from a real-world social network. The edges of graph have been categorized into three categories: home, workplaces, and social environment. The conditions needed to mitigate the spread of wild-type COVID-19 and the delta variant have been analyzed. Our purposeful agent based model has carefully executed tens of thousands of individual-based simulations. We propose simple relationships for the trade-offs between effective reproduction number (R _e), transmission rate, working hours, vaccination, and stay-at-home restrictions.

Results

We have found that the effect of a 13.6% increase in vaccination for wild-type (WT) COVID-19 is equivalent to reducing four hours of work or a one-day stay-at-home restriction. For the delta, 20.2% vaccination has the same effect. Also, since we can keep track of household and non-household infections, we observed that the change in household transmission rate does not significantly alter the R _e. Household infections are not limited by transmission rate due to the high frequency of connections. For the specifications of COVID-19, the R _e depends on the non-household transmissions rate.

Conclusions

Our findings highlight that decreasing working hours is the least effective among the non-pharmaceutical interventions. Our results suggest that policymakers decrease work-related activities as a last resort and should probably not do so when the effects are minimal, as shown. Furthermore, the enforcement of stay-at-home restrictions is moderately effective and can be used in conjunction with other measures if absolutely necessary.

Should I Help? Prosocial Behaviour during the COVID-19 Pandemic

The Movement Control Order (MCO) enacted during the COVID-19 pandemic has profoundly altered the social life and behaviour of the Malaysian population. Because the society is facing huge social and economic challenges that need individuals to work together to solve, prosocial behaviour is regarded as one of the most important social determinants. Because it is related with individual and societal benefits, participating in prosocial activities may be a major protective factor during times of global crisis. Rather than focusing only on medical and psychiatric paradigms, perhaps all that is necessary to overcome the COVID-19 risks is for individuals to make personal sacrifices for the sake of others. In reality, a large number of initiatives proven to be beneficial in decreasing viral transmission include a trade-off between individual and collective interests. Given its crucial importance, the purpose of this concept paper is to provide some insight into prosocial behaviour during the COVID-19 period. Understanding prosocial behaviour during the COVID-19 pandemic is crucial because it may assist in the establishment of a post-COVID society and provide useful strategies for coping with future crises.

SARS-CoV-2 Secondary Attack Rates in Vaccinated and Unvaccinated Household Contacts during Replacement of Delta with Omicron Variant, Spain

We performed a prospective, cross-sectional study of household contacts of symptomatic index case-patients with SARS-CoV-2 infection during the shift from Delta- to Omicron-dominant variants in Spain. We included 466 household contacts from 227 index cases. The secondary attack rate was 58.2% (95% CI 49.1%-62.6%) during the Delta-dominant period and 80.9% (95% CI 75.0%-86.9%) during the Omicron-dominant period. During the Delta-dominant period, unvaccinated contacts had higher probability of infection than vaccinated contacts (odds ratio 5.42, 95% CI 1.6-18.6), but this effect disappeared at ≈20 weeks after vaccination. Contacts showed a higher relative risk of infection (9.16, 95% CI 3.4-25.0) in the Omicron-dominant than Delta-dominant period when vaccinated within the previous 20 weeks. Our data suggest vaccine evasion might be a cause of rapid spread of the Omicron variant. We recommend a focus on developing vaccines with long-lasting protection against severe disease, rather than only against infectivity.

An empirical study of the effect of a flooding event caused by extreme rainfall on preventive behaviors against COVID-19

Since the outbreak of COVID-19, wearing masks, vaccinations, and maintaining a safe distance has become social behaviors advocated by the government and widely adopted by the public. At the same time, unpredictable natural disaster risks brought by extreme climate change compound difficulties during epidemics and cause systemic risks that influence the existing pattern of epidemic prevention. Therefore, it is necessary to explore the effect of natural disaster risk caused by climate change on the response to outbreaks in the context of the COVID-19 epidemic. This study will focus on individual-level epidemic prevention behaviors, taking as an example the significant risk of severe destructive flooding caused by heavy rains in Henan, China, on July 20, 2021, which claimed 398 lives, to explore the effect of floods on the preventive behaviors of residents in the hardest hit areas against COVID-19. Through the multi-stage stratified random sampling of the affected residents in Zhengzhou, Xinxiang, Hebi, Luoyang, Anyang, and other cities in Henan Province, 2,744 affected people were surveyed via questionnaires. Through the linear regression model and moderating effect analysis, the study found that after floods, the individual's flood risk perception and response behaviors significantly correlated with the individual's prevention behaviors against COVID-19. Specifically, both flood risk perception and response behaviors strengthened the individual's prevention behaviors. Furthermore, the study also found that community risk preparation behavior and social capital can moderate the above relationship to a certain extent. The research can guide risk communication under the compound risk scenario and prevent risky public behavior under the consistent presence of COVID-19 in the community.

The impact of COVID-19 vaccination program in the Republic of San Marino: focus on effectiveness of Gam-COVID-Vac

Objective

The adenovirus-based vaccine Gam-COVID-Vac (Sputnik V) showed promising effectiveness in a phase 3 clinical trial; however, data concerning its impact at a population level are scarce. The Republic of San Marino (RSM) conducted a SARS-CoV-2 vaccination programme mainly based (>80%) on Gam-COVID-Vac. Our aims were to investigate the impact of Gam-COVID-Vac vaccination programme and its effectiveness in a retrospective observational study based on the entire RSM population aged ≥12 years.

Methods

We calculated the incidence rate and the vaccine effectiveness (VE) in the entire RSM population not previously infected, against SARS-CoV-2 infection and COVID-19–related hospitalization, from 25 February to 1 October 2021, considering any vaccine and separately according to the vaccine used. Vaccine effectiveness was calculated using a multivariable negative binomial regression model as 1-Incidence Rate Ratio.

Results

During the study period, 21 568/28 791 (74.9%) not previously infected subjects received at least one dose of the Gam-COVID-Vac (84%) or BNT162b2, vaccines with 98% completing the vaccination schedule. Overall, 1634 SARS-CoV-2 infections and 166 COVID-19-related hospitalizations were observed with 17 COVID-19-related deaths reported. Incidence rates of SARS-CoV-2 infection and COVID-19-related hospitalization were 7.11 and 0.49/100 000 person-days in the fully vaccinated population, respectively. The adjusted overall VE was 67.6% (95% CI: 61.8–72.5) against SARS-CoV-2 infection and 87.9% (95% CI: 77.4–93.5) against COVID-19-related hospitalizations.

Gam-COVID-Vac against SARS-CoV-2 infection VE peaked 91.8% (95% CI: 86.3–95.1) in the first bimester from the second dose, declining to 57.8% (95% CI: 42.2–69.2) at 6 months. Protection against hospitalization with COVID-19 was overall 91.6% (95% CI: 81.5–96.2), with no relevant waning trend over time.

Discussion

Our study demonstrated the effectiveness of overall vaccination (Gam-COVID-Vac [84%] and BNT162b2 [16%]) in the prevention SARS-CoV-2 infection (pre-Omicron variant), waning over time but still with sustainable effectiveness against COVID-19-related hospitalization in the Republic of San Marino.

Systematic review of changed smoking behaviour, smoking cessation and psychological states of smokers according to cigarette type during the COVID-19 pandemic

OBJECTIVES

Although the global COVID-19 pandemic has increased interest in research involving high-risk smokers, studies examining changed smoking behaviours, cessation intentions and associated psychological states among smokers are still scarce. This study aimed to systematically review the literature related to this subject.

DESIGN

A systematic review of published articles on cigarettes and COVID-19-related topics DATA SOURCES: Our search was conducted in January 2021. We used the keywords COVID-19, cigarettes, electronic cigarettes (e-cigarettes) and psychological factors in PubMed and ScienceDirect and found papers published between January and December 2020.

DATA SELECTION

We included articles in full text, written in English, and that surveyed adults. The topics included smoking behaviour, smoking cessation, psychological state of smokers and COVID-19-related topics.

DATA EXTRACTION AND SYNTHESIS

Papers of low quality, based on quality assessment, were excluded. Thirteen papers were related to smoking behaviour, nine papers were related to smoking cessation and four papers were related to psychological states of smokers.

RESULTS

Owing to the COVID-19 lockdown, cigarette users were habituated to purchasing large quantities of cigarettes in advance. Additionally, cigarette-only users increased their attempts and willingness to quit smoking, compared with e-cigarette-only users.

CONCLUSIONS

Owing to the COVID-19 outbreak, the intention to quit smoking was different among smokers, according to cigarette type (cigarette-only users, e-cigarette-only users and dual users). With the ongoing COVID-19 pandemic, policies and campaigns to increase smoking cessation intentions and attempts to quit smoking among smokers at high risk of COVID-19 should be implemented. Additionally, e-cigarette-only users with poor health-seeking behaviour require interventions to increase the intention to quit smoking.

How has public perception of food safety and health risks changed a year after the pandemic and vaccines roll out?

The recent coronavirus pandemic (COVID-19) has caused unprecedented turmoil and spurred fears that have profoundly changed the public's social and health behaviours, including the perception of food safety risks. One year after the pandemic and the global vaccination campaign, the public perception of food safety and the changes in their hygiene behaviour, health risks concerns, and trust were studied in Jordan, Lebanon, and Tunisia using a cross-sectional online survey. The results of 538 subjects showed a rise in the frequency of hygiene practices, notably in handwashing. Sixty-four percent of the participants were vaccinated, a proportion made up mainly of the Jordanians and Lebanese. For 66% and 64% of the two population groups, respectively, there were no longer trust concerns about COVID-19 health risks following vaccination, whereas the worries about getting COVID-19 persisted for others. Only 47% of participants trusted eating food prepared by vaccinated food handlers. A great majority of the Tunisians (81%) showed varying degrees of concern about COVID-19 transmission from food and the lowest vaccination rate (33%). The current study demonstrated that the impact of vaccination policy positively affects public perception of food-related risks during the pandemic. On the other hand, 33% of the surveyed Jordanians and Tunisians lost trust in the health authorities' management of the pandemic, and 45% of the Lebanese still don't trust them. Communication strategies on health and food safety with the public still represent a challenge for these and probably other countries in the Middle East and North Africa (MENA). Strategies for building and maintaining public trust are crucial to curb persistent fear of food, hence, avoiding potential stigmatization affecting the food economy by promoting health awareness and positive changes in food safety perceptions for safer practices.

Facilitators and barriers to social distancing for young people during the COVID-19 pandemic

BACKGROUND

Social (or physical) distancing is an important transmission-prevention behaviour that has been endorsed to minimize COVID-19 transmission. This qualitative study explores the facilitators of and barriers to social distancing for young people during the COVID-19 pandemic, with recognition that young people represent a unique demographic group, with differing psychosocial needs and experiences to other age cohorts.

METHODS

Qualitative data was collected as part of a larger Qualtrics survey between July 28th 2020 and August 24th 2020. Eligible participants were young people living on the Island of Ireland, aged 16-25 years. The survey design was underpinned by the Capability, Opportunity, and Motivation model of behaviour change (COM-B). Semi-inductive thematic analysis was used to analyse comments collected via three free-text survey items. The COM-B model provided a thematic framework to organise subthemes extracted.

RESULTS

A total of N = 477 young people completed the survey, of which N = 347 provided comments for at least one of three free-text survey items. The majority of respondents lived in Northern Ireland (96%), the average age was 21 years, and most respondents were female (73%) and were students (81%). Key barriers identified included lack of environmental support for social distancing (lack of physical Opportunity to social distance), observing other people not social distancing (lack of social Opportunities supporting social distancing), and missing physical interaction from others (relating to the dissuading influence of automatic Motivational factors i.e. the influence of loneliness). Key facilitators included presence of clear and consistent environmental cues and availability of space to support social distancing (increasing physical Opportunity to social distance), increasing awareness and perceived consequences of risk of transmission (enhancing reflective Motivational factors i.e. perceived benefits (versus costs) of social distancing), and increasing opportunities to observe others' adhering to guidelines (increasing social Opportunities supporting social distancing).

CONCLUSIONS

These findings suggest that the actions and endorsement of peers and the physical design of environments have a key role in influencing social distancing behaviour among young people living in NI. The COM-B factors identified in this study can inform the development of tailored interventions using models such as the Behaviour Change Wheel. The findings of this study suggest that intervention functions based on peer modelling and physical environmental restructuring and enablement should be priortitised, however it is imperative that interventions are co-designed with young people to foster collaboration and empowerment.

Effectiveness of COVID-19 Vaccines in the General Population of an Italian Region before and during the Omicron Wave

We performed a cohort analysis of the entire population of Abruzzo, Italy, to evaluate the real-world effectiveness of SARS-CoV-2 vaccines against infection, COVID-19 hospitalization or death, over time and during the Omicron wave. All resident or domiciled subjects were included, and official vaccination, COVID-19, demographic, hospital and co-pay exemption datasets were extracted up to 18 February 2022. Multivariable analyses were adjusted for age, gender, hypertension, diabetes, major cardio- and cerebrovascular events, COPD, kidney diseases, and cancer. During the follow-up (average 244 days), 252,365 subjects received three vaccine doses (of BNT162b2, ChAdOx1 nCoV-19, mRNA-1273 or JNJ-78436735), 684,860 two doses, 29,401 one dose, and 313,068 no dose. Overall, 13.4% of the individuals were infected with SARS-CoV-2 (n = 170,761); 1.1% of them had severe COVID-19, and 0.6% died. Compared with the unvaccinated, those receiving two or three vaccine doses showed an 80% to 90% lower risk of COVID-19 hospitalization or death. Protection decreased during the Omicron wave and six months after the last dose, but it remained substantial. Lethal disease was uncommon during the Omicron wave and in the young population, even among the unvaccinated. Some of the current policies may need a re-evaluation in light of these findings. The results from the Omicron wave will inevitably require confirmation.

COVID-19 and pro-sociality: How do donors respond to local pandemic severity, increased salience, and media coverage?

Has the COVID-19 pandemic affected pro-sociality among individuals? After the onset of the pandemic, many charitable appeals were updated to include a reference to COVID-19. Did donors increase their giving in response to such changes? In order to answer these questions, we conducted a real-donation online experiment with more than 4200 participants from 149 local areas in England and over 21 weeks. First, we varied the fundraising appeal to either include or exclude a reference to COVID-19. We found that including the reference to COVID-19 in the appeal increased donations. Second, in a natural experiment-like approach, we studied how the relative local severity of the pandemic and media coverage about local COVID-19 severity affected giving in our experiment. We found that both higher local severity and more related articles increased giving of participants in the respective areas. This holds for different specifications, including specifications with location fixed effects, time fixed effects, a broad set of individual characteristics to account for a potentially changing composition of the sample over time and to account for health- and work-related experiences with and expectations regarding the pandemic. While negative experiences with COVID-19 correlate negatively with giving, both approaches led us to conclude that the pure effect of increased salience of the pandemic on pro-sociality is positive. Despite the shift in public attention toward the domestic fight against the pandemic and away from developing countries' challenges, we found that preferences did not shift toward giving more to a national project and less to developing countries.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10683-022-09753-y.

A BEHAVIORAL CHANGE MODEL TO ASSESS VACCINATION-INDUCED RELAXATION OF SOCIAL DISTANCING DURING AN EPIDEMIC

The success of mass vaccination campaigns may be jeopardized by human risky behaviors. For example, high level of vaccination coverage may induce early relaxation of social distancing. In this paper, we focus on the mutual influence between the decline in prevalence, due to the rise in the overall immunization coverage, and the consequent decrease in the compliance to social distancing measures. We consider an epidemic model where both the vaccination rate and the disease transmission rate are influenced by human behavior, which in turn depends on the current and past information about the spread of the disease. We highlight the impact of the information-related parameters on the transient and asymptotic behavior of the system that is on the early stage of the epidemic and its final outcome. Among the main results, we evidence that sustained oscillations may be triggered by the behavioral memory in the prevalence-dependent vaccination rate. However, the relaxation of social distancing may induce a switch from a cyclic regime to damped oscillations.

Effectiveness of Inactivated COVID-19 Vaccines Against Illness Caused by the B.1.617.2 (Delta) Variant During an Outbreak in Guangdong, China : A Cohort Study

BACKGROUND

Real-world evidence on inactivated COVID-19 vaccines against the highly transmissible B.1.617.2 (Delta) variant of SARS-CoV-2 is limited, leaving an important gap in the evidence base about inactivated COVID-19 vaccines for use by immunization programs.

OBJECTIVE

To estimate inactivated vaccine effectiveness (VE) against the B.1.617.2 variant.

DESIGN

Retrospective cohort study.

SETTING

The study was based on the first outbreak of the B.1.617.2 variant in mainland China that was discovered and traced in Guangdong in May and June 2021.

PARTICIPANTS

10 805 adult case patients with laboratory-confirmed infection and close contacts.

MEASUREMENTS

Participants were categorized as unvaccinated, partially vaccinated (1 dose), and fully vaccinated (2 doses). We estimated VE against the primary outcome of pneumonia and the secondary outcomes of infections, symptomatic infections, and severe or critical illness associated with the B.1.617.2 variant.

RESULTS

Results are reported in the order of outcome severity. Of 10 805 participants, 1.3% contracted infections, 1.2% developed symptomatic infections, 1.1% had pneumonia, and 0.2% had severe or critical illness. The adjusted VEs of full vaccination were 51.8% (95% CI, 20.3% to 83.2%) against infection, 60.4% (CI, 31.8% to 88.9%) against symptomatic infection, and 78.4% (CI, 56.9% to 99.9%) against pneumonia. Also, full vaccination was 100% (CI, 98.4% to 100.0%) effective against severe or critical illness. By contrast, the adjusted VEs of partial vaccination against infection, symptomatic infection, and pneumonia were 10.7% (CI, -41.2% to 62.6%), 6.8% (CI, -47.4% to 61.0%), and 11.6% (CI, -42.6% to 65.8%), respectively.

LIMITATION

Observational study with possible unmeasured confounders; insufficient data to do reliable subgroup analyses by age and vaccine brand.

CONCLUSION

Full vaccination with inactivated vaccines is effective against the B.1.617.2 variant. Effort should be made to ensure full vaccination of target populations.

PRIMARY FUNDING SOURCE

National Natural Science Foundation of China and Key-Area Research and Development Program of Guangdong Province.

Vaccination strategies and transmission of COVID-19: Evidence across advanced countries

Given limited supply of approved vaccines and constrained medical resources, design of a vaccination strategy to control a pandemic is an economic problem. We use time-series and panel methods with real-world country-level data to estimate effects on COVID-19 cases and deaths of two key elements of mass vaccination - time between doses and vaccine type. We find that new infections and deaths are both significantly negatively associated with the fraction of the population vaccinated with at least one dose. Conditional on first-dose coverage, an increased fraction with two doses appears to offer no further reductions in new cases and deaths. For vaccines from China, however, we find significant effects on both health outcomes only after two doses. Our results support a policy of extending the interval between first and second doses of vaccines developed in Europe and the US. As vaccination progresses, population mobility increases, which partially offsets the direct effects of vaccination. This suggests that non-pharmaceutical interventions remain important to contain transmission as vaccination is rolled out.

Slovak parents' mental health and socioeconomic changes during the COVID-19 pandemic

The changes in people's mental health have become one of the hot topics during the COVID-19 pandemic. Parents have been said to be among the most vulnerable groups in terms of the imposed anti-pandemic measures. The present paper analyzes the trends in mental health indicators in a sample of Slovak parents (N = 363) who participated in four waves of data collection over a year and a half of the COVID-19 pandemic. The mental health indicators were represented by general levels of depression and anxiety as well as COVID-related stress and anxiety. While there were only minor changes in depression and anxiety, the dynamic in COVID-related stress and especially anxiety was more noteworthy. Besides some exceptions, the results hold even after controlling for the socioeconomic situation. The gender differences in the mental health trends were found to be negligible. Overall, we observed no substantial deterioration in the mental health indicators across the four waves of the study.

An analysis of the COVID-19 vaccination campaigns in France, Israel, Italy and Spain and their impact on health and economic outcomes

Objectives

This paper presents an overview of the vaccination campaigns in France, Israel, Italy and Spain during the first eleven months from the first COVID-19 vaccine approval (Dec 2020 - Nov 2021). These four countries were chosen as they share similar socioeconomic, and epidemiological profiles and adopted similar vaccination strategies.

Methods

A rapid review of available primary data from each country was conducted. Data were collected from official government documents whenever possible, supplemented by information from international databases and local reports. The data were analysed via descriptive and graphical analysis to identify common patterns as well as significant divergences in the structural changes of countries’ healthcare systems during the pandemic, outcomes of the vaccination roll-out, and their impact on contextual policies.

Results

The four countries adopted similar interventions to protect and strengthen their healthcare systems. The effective coordination between the governance levels, ability to ensure a large supply of doses, and trust towards health authorities were amongst the determinants for more successful vaccination outcomes. The analysis reports a positive impact of the COVID-19 vaccines on epidemiological, political and economic outcomes. We observed some evidence of a negative association between increased vaccine coverage and fatalities and hospitalisation trends.

Conclusions

The strengths and weaknesses of COVID-19 pandemic crisis management along with the various strategies surrounding the vaccination roll-out campaigns may yield lessons for policymakers amidst such decisions, including for future pandemics.

Lay summary

This paper presents an overview of the vaccination campaigns in France, Israel, Italy and Spain during the first eleven months following approval of the first COVID-19 vaccine (Dec 2020 - Nov 2021). These four countries were chosen as they share similar demographic, socioeconomic, and epidemiological profiles, and adopted similar vaccinations strategies. Effective coordination between governance levels, ability to ensure a large supply of doses, and trust towards health authorities were amongst the determinants for successful outcomes of vaccination campaigns. The strengths and weaknesses of COVID-19 pandemic crisis management, along with the various strategies surrounding the vaccination roll-out campaigns may yield lessons for policymakers amidst such decisions, including for future pandemics.

Factors Associated with COVID-19 Vaccine Hesitancy among Visible Minority Groups from a Global Context: A Scoping Review

Vaccine hesitancy is one of the top ten greatest threats to global health. During the COVID-19 era, vaccine hesitancy poses substantial risks, especially in visible minorities, who are disproportionately affected by the pandemic. Although evidence of vaccine hesitancy exists, there is minimal focus on visible minorities and the reasons for hesitancy in this group are unclear. Identifying these populations and their reasons for vaccine hesitancy is crucial in improving vaccine uptake and curbing the spread of COVID-19. This scoping review follows a modified version of the Arksey and O'Malley strategy. Using comprehensive search strategies, advanced searches were conducted on Medline, CINAHL, and PubMed databases to acquire relevant articles. Full-text reviews using inclusion and exclusion criteria were performed to extract themes of vaccine hesitancy. Themes were grouped into factors using thematic qualitative analysis and were objectively confirmed by principal component analysis (PCA). To complement both analyses, a word cloud of titles and abstracts for the final articles was generated. This study included 71 articles. Themes were grouped into 8 factors and the top 3 recurring factors were safety and effectiveness of the vaccine, mistrust, and socioeconomic characteristics. Shedding light on these factors could help mitigate health inequities and increase overall vaccine uptake worldwide through interventions and policies targeted at these factors. Ultimately, this would help achieve global herd immunity.

Policy Stringency, Handwashing and COVID-19 cases: Evidence from Global dataset

Objective

: Since the COVID-19 pandemic, many governments globally have introduced policy measures to contain the spread of the virus. Popular COVID-19 containment measures include lockdowns of various forms (aggregated into government response stringency index [GRSI]) and handwashing (HWF). The effectiveness of these policy measures remains unclear in the academic literature. This study, therefore, examines the effect of government policy stringency and handwashing on total daily reported COVID-19 cases.

Method

: We use a comprehensive dataset of 176 countries to investigate the effect of government policy stringency and handwashing on daily reported COVID-19 cases. In this study, we apply the Lewbel (2012) two-stage least squares technique to control endogeneity.

Results

: Our results indicated that GRSI significantly contributes to the increase in the total and new confirmed cases of COVI-19. Sensitivity analyses revealed that the 1st, 4th, and 5th quintiles of GRIS significantly reduce total confirmed cases of COVID-19. Also, the result indicated that while the 1st quintile of GRIS contributes significantly to reducing the new confirmed cases of COVID-19, the 3rd, 4th, and 5th quintiles of GRSI contribute significantly to increasing the new confirmed cases of COVID-19. The results indicated that HWF reduces total and new confirmed cases of COVID-19; however, such effect is not robust to income and regional effects. Nonlinear analysis revealed that while GRSI has an inverted U-shaped relationship with total and new confirmed cases of COVID-19, HWF has a U-shaped relationship.

Conclusion

: We suggest that policymakers should focus on raising awareness and full engagement of all members of society in implementing public health policies rather than using stringent lockdown measures.