The study analyses in situ CO2 mole fraction, 14CO2, and fossil based excess CO2 mole fraction (Cfoss) data at Hegyhátsál (HUN) rural monitoring station (Central Europe) supplemented by passive monitoring of 14C content of tree-rings. Through the observed period (2014–2020) we focused on revealing trends in atmospheric CO2 and 14C levels, particularly during the year of the first COVID lockdown, in comparison to the preceding five years. In addition, monthly integrated samples of atmospheric CO2 and tree-rings from the six years were subjected to 14C analysis. The passive tree-ring measurements focuses on two major urban areas (Budapest and Debrecen) in Hungary, along with the rural monitoring site. Results show a steady increase in CO2 levels at HUN between 2014 and 2020. The calculated fossil based excess CO2 concentrations for the initial year of COVID are in good agreement with the previous five-year averages both at 115 m and 10 m elevations. These results also show seasonal variations of CO2 mole fractions, peaking in winter and decreasing in summer. Tree-ring results from Debrecen show a good alignment with the results of the atmospheric monitoring station, and it does not show a significant fossil contribution in the urban background area during the vegetation periods. Tree-ring results from Budapest show a stronger fossil contribution compared to the Debrecen ones. Our atmospheric CO2 results do not show a large decrease in fossil CO2 atmospheric contribution during the first lockdown. We found that the use of this passive CO2 monitoring technique can provide a valuable tool for investigating such differences.

This study is a conceptual replication of Kelley & Schmeichel (PLOS ONE 10: e0144228, 2015), which found that thinking about death reduces delay discounting. Unlike the original study, the current study was conducted in an environment where there was a real and tangible mortality threat across the world, that is, COVID-19. Contrary to the findings of the original study, results of the current study revealed that thinking about death increases delay discounting, such that participants who were primed with death thoughts traded “₺200 now” for “₺342.35 three months later,” whereas those in the control condition traded “₺200 now” for “₺319.27 three months later”. The current study also explored the moderating roles of goal orientation and self-esteem in the effect of mortality salience on delay discounting; however, it failed to provide evidence for the moderating roles of these variables.

This article surveys the rapidly growing literature that examined the influence of Covid-19 on preferences. Based on 33 studies, the article examines how the pandemic impacted altruism, cooperation, trust, inequity aversion, risk-taking, and patience/time discounting. Even though the survey suggests the effect of the pandemic on preferences is heterogeneous, some noticeable patterns can be observed in the literature. First, in the case of incentivized preference elicitation, there is weak evidence that the pandemic positively influenced altruism and had no significant impact on time preferences or patience. Second, many studies that used balanced panel data and incentivized preference elicitation mechanisms do not find a significant effect of the pandemic on preferences. Last, studies that used unincentivized methods to elicit preferences show relatively higher variability in results when compared to the studies that used incentivized methods for preference elicitation. The organized synthesis and several noticeable patterns can help future research focusing on preference stability during Covid-19 and other unfavorable events.

Governments across the world have implemented restrictive policies to slow the spread of COVID-19. Recommended face mask use has been a controversially discussed policy, among others, due to potential adverse effects on physical distancing. Using a randomized field experiment (N = 300), we show that individuals kept a significantly larger distance from someone wearing a face mask than from an unmasked person during the early days of the pandemic. According to an additional survey experiment (N = 456) conducted at the time, masked individuals were not perceived as being more infectious than unmasked ones, but they were believed to prefer more distancing. This result suggests that wearing a mask served as a social signal that led others to increase the distance they kept. Our findings provide evidence against the claim that mask use creates a false sense of security that would negatively affect physical distancing. Furthermore, our results suggest that behavior has informational content that may be affected by policies.

Laboratory experiments have been often replaced by online experiments in the last decade. This trend has been reinforced when academic and research work based on physical interaction had to be suspended due to restrictions imposed to limit the spread of Covid-19. Therefore, data quality and results from web experiments have become an issue which is currently investigated. Are there significant differences between lab experiments and online findings? We contribute to this debate via an experiment aimed at comparing results from a novel online protocol with traditional laboratory settings, using the same pool of participants. We find that participants in our experiment behave in a similar way across settings and that there are at best weakly significant and quantitatively small differences in behavior observed using our online protocol and physical laboratory setting.

The personal experience of events such as financial crises and natural disasters can alter economic preferences. We administered a repeated cross-sectional preference survey during the early stages of the COVID-19 outbreak, collecting three bi-weekly samples from participants recruited through Amazon Mechanical Turk. The survey elicits economic preferences, self-reported fear of the pandemic, and beliefs about economic and health consequences. Preferences varied over time and across regions, and self-reported fear of the pandemic explains this variation. These findings suggest caution about the generalizability of some types of experimental work during times of heightened fear.

Access to information via social media is one of the biggest differentiators of public health crises today. During the early stages of the Covid-19 outbreak in January 2020, we conducted an experiment in Wuhan, China to assess the impact of viral social media content on pro-social and trust behaviours and preferences towards risk taking with known and unknown probabilities. Prior to the experiment, participants viewed one of two videos that had been widely and anonymously shared on Chinese social media: a central government leader visiting a local hospital and supermarket, or health care volunteers transiting to Wuhan. In a control condition, participants watched a Neutral video, unrelated to the crisis. Viewing one of the leadership or volunteer videos leads to higher levels of pro-sociality and lesser willingness to take risks in an ambiguous situation relative to the control condition. The leadership video, however, induces lower levels of trust. We provide evidence from two post-experiment surveys that the video’s impact on pro-sociality is modulated by influencing the viewer’s affective emotional state.

The coronavirus disease 2019 (COVID-19) pandemic has caused health issues worldwide. Studies have suggested that modulation of the gut microbiota could attenuate the severity of COVID-19 symptoms. In light of this, we explored the effects of the prebiotic dietary fibre partially hydrolyzed guar gum (PHGG) on SARS-CoV-2 infection in a Syrian hamster model, hypothesizing that modulation of the gut microbiome and intestinal metabolites through PHGG administration would improve COVID-19 disease outcomes. Eight hamsters each were assigned to the PHGG administration and control groups. The PHGG group was given a diet supplemented with 5% PHGG for two weeks. Consequently, PHGG improved the host survival rate to 100% compared to 25% of the control group (P = 0.003) and attenuated morbid weight loss. Another non-infected set of hamsters was used for the analysis of the gut microbiome composition with 16S rRNA amplicon sequencing, serum, and faecal metabolites with GC–MS and LC–MS. PHGG altered the gut microbiome composition and increased the relative abundances of Ileibacterium, Bifidobacterium, and Prevotella. Furthermore, it elevated the concentrations of faecal valeric acid, propionic acid, ursodeoxycholic acid, and serum deoxycholic acid. Taken together, our data suggest that the prebiotic PHGG modulates gut metabolites and has the potential to reduce COVID-19 morbidity.

Global health security in the Biden-Harris Administration has been a dynamic area of engagement, starting with the COVID-19 response, to strengthening and reforming the World Health Organization, to bolstering regional partnerships, and securing financing for pandemic preparedness. Sustained commitment to bilateral, regional, and multilateral cooperation will ensure that the United States stands ready to address any future health challenges.

The COVID-19 pandemic posed new challenges for leaders, requiring behavior change and public self-compliance. Stereotypically feminine qualities, such as compassion and a good approach to people, may have helped achieve these goals, rendering the pandemic a “feminine crisis.” The special nature of this crisis, along with media attention on female-led countries successfully managing the pandemic, raises the question of whether female leaders would be perceived as more competent in handling such a crisis. In an experimental study conducted on a representative sample in Poland, we assessed whether female prime minister candidates or candidates with feminine traits had an advantage when their competence in managing a large-scale pandemic was evaluated. Surprisingly, we found that, contrary to national security and economic crises (where male or masculine candidates tend to be advantaged), women or feminine candidates were not perceived as having an advantage in managing a COVID-19 type crisis. Furthermore, conservative participants seemed to perceive male candidates as more competent, even in the pandemic context. Although the differences were small in magnitude, they suggest that even in a potentially “feminine crisis,” women do not fare better than men, while men still fare better in stereotypically male crises.

Adolescence and young adulthood are sensitive developmental periods to environmental influences. Investigating pre-emptive measures against stressors, such as those associated with the COVID-19 pandemic, on mental health is crucial. We aimed to synthesize evidence on pre-pandemic resilience factors shaping youth mental health outcomes during this period. For this pre-registered systematic review, we searched seven databases for longitudinal studies of youth populations affected by the COVID-19 pandemic, assessing a priori defined resilience factors at the individual, family, or community level before the pandemic. Studies required validated mental health or wellbeing measures collected both before and during the pandemic. Study quality was assessed using the corresponding NIH Quality Assessment Tool. From 4,419 unique records, 32 studies across 12 countries were included, using 46 distinct resilience measures. Due to the heterogeneity of study designs, we applied a narrative synthesis approach, finding that resilience factors were generally associated with better mental health outcomes both prior to and during the pandemic. However, most factors did not mitigate pandemic-related mental health effects. Nonetheless, family-level resilience factors emerged as promising under specific conditions. Study quality was generally fair, with concerns in resilience assessment and sampling quality. Future research should prioritize rigorous study designs and comprehensive resilience assessments.

As COVID-19 spread rapidly during the early months of the pandemic, many communities around the globe anxiously waited for a vaccine. At the start of the pandemic, it was widely believed that Africa would be a significant source of infection, and thus, vaccinating African communities became a primary goal among local and global health authorities. However, when the COVID-19 vaccine became available in March 2021 in Sierra Leone, many people viewed it with scepticism and hesitation. While much literature has focused on access and distribution-related challenges for vaccination in the region, a growing number of studies discuss vaccine hesitancy as driving low vaccine uptake. Shifting attention to understanding the determinants of vaccine hesitancy remains fundamental to increasing vaccination rates, as negative vaccine perceptions tend to delay or prevent vaccination. This study sought to do this by assessing, through semi-structured qualitative interviews, vaccine-related attitudes and experiences of residents of Sierra Leone’s Kono District. In contrast to studies that utilise “knowledge-deficit” models of belief, however, this study drew upon the vaccine anxieties framework (Leach and Fairhead, 2007), which views vaccines as being imbued with personal, historical, and political meaning. Findings suggest that important bodily, social, and political factors, including fear of side effects, the spread of misinformation prompted by poor messaging strategies, and distrust of government and international actors, influenced people’s COVID-19 vaccine attitudes and behaviours. It is hoped that the study’s findings will inform future policies and interventions related to vaccine uptake in Africa and globally.