The COVID-19 pandemic currently affects populations worldwide. Although everyone is susceptible to the virus, there are numerous accounts of the pandemic having a greater impact on lower socioeconomic groups and minorities, which is a ubiquitous phenomenon. It is essential for public health administrations and governments to uncover and understanding these inequities to develop proper intersectoral policies to tackle this crisis. Therefore, developing a conceptual framework on this topic, describing the social mechanisms that explain the unjust distribution of the incidence and mortality of COVID-19, is a key task. The aim of this paper is to adapt the framework on social determinants of health from the World Health Organization to the specifics of COVID-19 pandemic. Thus, it identifies and explains the structural and intermediate determinants involved in this pandemic, and adds some new elements (such as the role of the oppression systems and communication) which may help to understand, and ultimately tackle, social inequities in COVID-19 distribution.

COVID-19 lockdowns greatly affected the mental health of populations and collectives. This study compares the mental health and self-perceived health in five countries of Latin America and Spain, during the first wave of COVID 19 lockdown, according to social axes of inequality. This was a cross-sectional study using an online, self-managed survey in Brazil, Chile, Ecuador, Mexico, Peru, and Spain. Self-perceived health (SPH), anxiety (measured through GAD-7) and depression (measured through PHQ-9) were measured along with lockdown, COVID-19, and social variables. The prevalence of poor SPH, anxiety, and depression was calculated. The analyses were stratified by gender (men = M; women = W) and country. The data from 39,006 people were analyzed (W = 71.9%). There was a higher prevalence of poor SPH and bad mental health in women in all countries studied. Peru had the worst SPH results, while Chile and Ecuador had the worst mental health indicators. Spain had the lowest prevalence of poor SPH and mental health. The prevalence of anxiety and depression decreased as age increased. Unemployment, poor working conditions, inadequate housing, and the highest unpaid workload were associated with worse mental health and poor SPH, especially in women. In future policies, worldwide public measures should consider the great social inequalities in health present between and within countries in order to tackle health emergencies while reducing the health breach between populations.

Sedentary behavior is a risk factor for comorbidities independently of physical activity. Some studies have reported screen time as an unhealthier form of sedentary behavior. This study assessed the association between recreational screen-time behavior and self-perceived health. This is a cross-sectional study. As part of the Salut als Carrers Project, in 2018 a survey was conducted in a representative sample (n ​= ​795) of residents aged ​≥ ​18 years living in the borough of Horta, in Barcelona. The survey assessed self-perceived health, recreational screen-time behavior on working and non-working days (Marshall questionnaire), leisure time physical activity (International Physical Activity Questionnaire [IPAQ] long form), socioeconomic status, and age. We analyzed associations between self-perceived health and recreational screen-time sedentary behavior, with adjustment of robust Poisson models for social class, age, and leisure physical activity. All analyses were stratified by gender. A total of 82.7% of men and 82.5% of women reported sedentary behavior during recreational screen time of ≥3 ​h/day on working days, and 63.9% of men and 65.8% of women on non-working days. Spending ≥3 ​h/day sitting in front of a screen for leisure was associated with poor self-perceived health only on working days for men [PR ​= ​1.87 (1.13–3.09)] but not for women [PR ​= ​1.32 (0.82–2.11)] regardless of leisure physical activity, age, and social class. In adults, sedentary behavior during recreational screen time on working days is adversely associated with perceived ill health in men, irrespective of leisure time physical activity. Public health interventions could benefit from promoting a reduction in leisure screen sitting time after working hours.

Background: SARS-CoV-2 booster vaccination remains essential to prevent severe COVID-19, particularly in vulnerable populations such as older adults. This study evaluated the durability and dynamics of immune responses following booster vaccination(s) in >65-year-old individuals and examined their association with protection against new infections. Methods: Immune responses were evaluated at 3, 9, and 15 months post-booster, measuring SARS-CoV-2-specific IgG antibodies against spike [IgG(S)] and nucleocapsid [IgG(N)] proteins, neutralizing activity against the Omicron BA.2 variant, and cellular immunity. A subset of participants was tested before booster administration. Regression analyses examined the influence of clinical and immunological factors—including a bivalent fourth dose—on infection risk over time. Results: Booster vaccination significantly enhanced IgG(S) and neutralizing capacity, peaking at 3 months. Although a decline was observed by 9 months, responses remained above baseline. Individuals with prior SARS-CoV-2 infection exhibited higher IgG(S) levels and neutralizing titers, and significantly lower reinfection rates (15%), compared to uninfected individuals. A fourth vaccine dose further increased IgG(S) levels. While neutralizing capacity was not consistently enhanced by the fourth dose, recipients experienced a lower rate of new infections. Immune trajectory analyses revealed that breakthrough infections elicited strong humoral responses comparable to those seen in previously infected individuals, highlighting the role of hybrid immunity. Conclusions: In older adults, booster vaccination induces durable immune responses, with hybrid immunity offering enhanced protection. A fourth dose boosts antibody levels and reduces infection risk, supporting its use in this high-risk group. Continued monitoring is needed to determine the long-term effectiveness of boosters, particularly against emerging variants.

Background: Since the 2008 economic crisis in Spain, overall fertility has continued to decrease, while urban inequalities have increased. There is a general lack of studies of fertility patterns in small-areas of Spanish cities. We explored the effects of the economic crisis on fertility during three time periods in urban settings in Spain. Methods: We studied the distribution of fertility rates among women (15–49 years) from Spain and low-middle income countries (LIC) who were living in 13 Spanish cities. We mapped fertility and the MEDEA socioeconomic deprivation index in small-areas, and analyzed age-related trends in fertility rates. We performed an ecological regression analysis of fertility and the deprivation index in two pre-crisis periods (1999–2003 and 2004–2008) and one crisis period (2009–2013). Fertility rates were calculated and smoothed using the hierarchical Bayesian model (BYM). Results: Higher fertility was generally associated with socioeconomic deprivation, with adjustment for the mothers’ age and nationality. While Spanish citizens tended to delay childbearing throughout the three study periods, fertility increased among Spanish adolescents from deprived urban areas during the economic crisis. There was a general decline in fertility among immigrants after the crisis, especially in southern cities. Overall, fertility appeared to be stable, with higher fertility in more deprived areas. Conclusion: Increased unemployment and changes to government family policies may have contributed to delayed childbearing in Spain. For immigrants, more restrictive immigration policies may have played a crucial role in decreasing fertility rates. Reforming such policies will be key for better reproductive rights and improved fertility rates across all population cohorts in Spain.