Is the Pandemic Wearing Us Out? A Cross-Sectional Study of the Prevalence of Fatigue in Adult Twins without Previous SARS-CoV-2 Infection

During the pandemic, mental health was not only impaired in people after a SARS-CoV-2 infection, but also in people without previous infection. This is the first study on twins without prior SARS-CoV-2 infection to estimate the influence of genetic components and shared as well as individual environments on pandemic-associated fatigue. The study sample included 55 monozygotic and 45 dizygotic twin pairs. A total of 34.5% reported an increase in fatigue since the pandemic. A significant correlation was shown between the responses within monozygotic (χ(2)[1] = 11.14, p = 0.001) and dizygotic pairs (χ(2)[1] = 18.72, p < 0.001). In all pandemic-associated fatigue dimensions, individual environment (ranging from e(2) = 0.64 to e(2) = 0.84) and heritability (ranging from h(2) = 0.32 to h(2) = 1.04) seem to have the highest impact. The number of comorbidities significantly correlated with physical fatigue (Spearman’s ρ = 0.232, p < 0.001) and psychological impairment due to pandemic measures with the total fatigue score (Spearman’s ρ = 0.243, p < 0.001). However, calculated ANCOVAs with these significant correlations as covariates showed no significant influence on the mean values of the respective fatigue dimensions. Susceptibility to pandemic-associated fatigue may be genetically and environmentally determined, while intensity is also influenced by individual components. The prevalence of fatigue is high even in individuals without prior SARS-CoV-2 infection. Future mental health prevention and intervention programs should be implemented to alleviate the impact of the pandemic on the global population.