(1) Background: The use of social media has become an integral part of adolescents’ daily lives. However, the intensive use of social media can develop into a health-threatening addiction, but unfavourable health consequences can occur even with less use. Social media user groups categorized as no-risk, moderate risk (of developing problematic behaviour), and problematic use were examined with reference to their prevalence, their associations with individual determinants and health, and the increased health risk between groups. (2) Methods: The Finnish nationally representative HBSC data (persons aged 11, 13, and 15, n = 3408) and descriptive and binary logistic regression analysis were applied. (3) Results: Problematic social media use (9.4%) was most common among older age groups, and among persons with moderate/low school achievement, low health literacy, and low parental monitoring. Belonging to a moderate risk group (33.5%) was most frequent among girls, and among adolescents with low/moderate parental monitoring and health literacy. All the negative health indicators systematically increased if the respondent belonged to a moderate risk or problematic use group. (4) Conclusions: The study confirmed the association between problematic social media use and negative health outcomes and highlighted the need to pay close attention to adolescents at moderate risk who exhibited negative health outcomes.

(1) Background: There is a need for studies on population-level health literacy (HL) to identify the current state of HL within and between countries. We report comparative findings from 10 European countries (Austria, Belgium (Fl), Czechia, England, Estonia, Finland, Germany, Macedonia, Poland, and Slovakia) on adolescents’ HL and its associations with gender, family affluence (FAS), and self-rated health (SRH). (2) Methods: Representative data (N = 14,590; age 15) were drawn from the HBSC (Health Behavior in School-Aged Children) study. The associations between HL, gender, FAS, and SRH were examined via path models. (3) Results: The countries exhibited differences in HL means and in the range of scores within countries. Positive associations were found between FAS and HL, and between HL and SRH in each country. Gender was associated with differences in HL in only three countries. HL acted as a mediator between gender and SRH in four countries, and between FAS and SRH in each country. (4) Conclusions: The findings confirm that there are differences in HL levels within and between European countries, and that HL does contribute to differences in SRH. HL should be taken into account when devising evidence-informed policies and interventions to promote the health of adolescents.

Summary: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel virus in the coronavirus family, causing the coronavirus disease (COVID-19). Biomedical vaccines are key but alongside biomedical vaccines, a social vaccine can be similarly useful to prevent infection from SARS-CoV-2, if applied as a health promotion strategy. In order to slow down and control the spread of SARS-CoV-2, applying the social vaccine concept should be considered in parallel. From a health promotion perspective, a social vaccine is a process of social and political mobilization driven by governmental and non-governmental organizations aiming at populations by applying interventions such as health communication, education and mass media campaigns as well as determinant-based programs to address environmental factors influencing personal behavior and community capacities to cope with and overcome the societal burdens of COVID-19. In this context, health literacy is significant, as seen in the role it plays in empowering citizens during the COVID-19 pandemic and enabling them to deal with health information considering COVID-19. As a public health strategy, health literacy as a social vaccine will enable individuals and communities to mitigate the spread of the virus by understanding and applying information as provided through governments and health authorities. The aim of this article is to explore health literacy as a promising social vaccine and opportunity to utilize social vaccination and thus be considered as a key public health approach—both bottom-up and top-down—to support the combat of COVID-19 and future states of emergency.

Background and aims: There is currently no cross‐national validation of a scale that measures problematic social media use (SMU). The present study investigated and compared the psychometric properties of the social media disorder (SMD) scale among young adolescents from different countries. Design: Validation study. Setting and participants: Data came from 222 532 adolescents from 44 countries participating in the health behaviour in school‐aged children (HBSC) survey (2017/2018). The HBSC survey was conducted in the European region and Canada. Participants were on average aged 13.54 years (standard deviation = 1.63) and 51.24% were girls. Measurement: Problematic SMU was measured using the nine‐item SMD scale with dichotomous response options. Findings: Confirmatory factor analyses (CFA) showed good model fit for a one‐factor model across all countries (minimum comparative fit index (CFI) and Tucker–Lewis index (TLI) = 0.963 and 0.951, maximum root mean square error of approximation (RMSEA) and standardized root mean square residual (SRMR) = 0.057 and 0.060), confirming structural validity. The internal consistency of the items was adequate in all countries (minimum alpha = 0.840), indicating that the scale provides reliable scores. Multi‐group CFA showed that the factor structure was measurement invariant across countries (ΔCFI = −0.010, ΔRMSEA = 0.003), suggesting that adolescents’ level of problematic SMU can be reliably compared cross‐nationally. In all countries, gender and socio‐economic invariance was established, and age invariance was found in 43 of 44 countries. In line with prior research, in almost all countries, problematic SMU related to poorer mental wellbeing (range β _STDY = 0.193–0.924, P < 0.05) and higher intensity of online communication (range β _STDY = 0.163–0.635, P < 0.05), confirming appropriate criterion validity. Conclusions: The social media disorder scale appears to be suitable for measuring and comparing problematic social media use among young adolescents across many national contexts.

Background: The concept of health literacy (HL) may help us to better understand the mechanisms leading to health disparities, and to focus on the factors that can be influenced. However, not much is yet known about how HL is related to health disparities, or whether the association exists among adolescents. The aim of the study was to examine the associations between structural stratifiers, HL and health indicators among adolescents. Methods: The nationally representative Finnish Health Behaviour in School-aged Children survey data (n=3833) were collected from 13- and 15-year-old pupils in the spring of 2014. Pearson correlation coefficients were calculated, and separate path models were estimated for the perceived health and health behaviour measures. Results: HL was found to be an independent factor explaining disparities in health. Higher HL was related to positive health outcomes. HL also acted as a mediator between health behaviours and structural stratifiers, except for gender. School achievement and educational aspirations were among the factors explaining the HL level, which in turn, explained the health indicators. Conclusion: The concept of HL is of use in understanding health disparities. In particular, HL provides a mechanism via which school achievement and educational plans affect health outcomes. Low HL places adolescents who have poor school achievement and who do not intend to continue on an academic path in an unequal position with respect to their health.