The Lasting Legacy of COVID-19: Exploring the Long-Term Effects of Infection, Disease Severity, and Vaccination on Health and Cognitive Function

Abstract

COVID-19 affects a variety of organs and systems of the body including the central nervous system. Recent research has shown that COVID-19 survivors often experience neurological and psychological complications that can last for months after infection. We conducted a large internet study using online tests to analyze the effects of SARS-CoV-2 infection, COVID-19 severity, and vaccination on health, intelligence, memory, and information processing precision and speed in a cohort of 4,446 subjects. We found that both SARS-CoV-2 infection and COVID-19 severity were associated with negative impacts on patients' health. Furthermore, we observed a negative association between COVID-19 severity and cognitive performance. Younger participants had a higher likelihood of SARS-CoV-2 contraction, while the elderly had a higher likelihood of severe COVID-19 and vaccination. The association between age and COVID-19 severity was primarily mediated by older participants' impaired long-term health. Vaccination was positively associated with intelligence and the precision of information processing. However, the positive association between vaccination and intelligence was likely mediated by achieved education, which was itself strongly associated with the likelihood of being vaccinated.

Is Recovery Just the Beginning? Persistent Symptoms and Health and Performance Deterioration in Post-COVID-19, non-hospitalised University Students - A Cross-Sectional Study

“…The minimal or absent impact of merely contracting the infection on physical and mental health and cognitive performance, which contrasts with results of many already published studies, e.g. (Altuna, Sánchez-Saudinós, Lleó, & 2021; Delgado-Alonso et al, 2022; Flegr & Latifi, 2023; Havervall et al, 2021; Lamontagne et al, 2021; Lu et al, 2020; Marchi et al, 2023; Mazza et al, 2020; O’Mahoney et al, 2023; Zhao et al, 2020) could be related to the fact that all students included in our study were younger than 31 years old (95% were 20-24 years old). As is often the case with such a young population, most students experienced a relatively mild form of COVID-19; only about 20% described it as “severe flu,” and none of the study participants was hospitalized due to COVID-19.…”

“…Our results align with previous studies that have identified a correlation between COVID-19 severity and subsequent declines in physical health (Flegr & Latifi, 2023; Han, Zheng, Daines, & Sheikh, 2022; Iqbal et al, 2021; Mizrahi et al, 2023), mental health challenges (Putri, Arisa, Hananto, Hariyanto, & Kurniawan, 2021; Shanbehzadeh, Tavahomi, Zanjari, Ebrahimi-Takamjani, & Amiri-Arimi, 2021; Zeng et al, 2023), and cognitive deficits (Ariza et al, 2023; Guo et al, 2022; Miskowiak et al, 2021). Collectively, these findings suggest that individuals with a history of more severe COVID-19 symptoms typically face more pronounced post-infection complications.…”

“…Accordingly, examining the source variables results corrected for type I errors, our findings regarding ‘orthopedic disorders’ in males and ‘metabolic disorders’ and ‘physical health disparity’ in females were in agreement with those studies that observed deteriorated physical health in these areas in post-COVID19 patients (for reviews on orthopedic disorders see (Slouma, Abbes, Kharrat, & Gharsallah, 2022) and (Slouma et al, 2023) and for a review on metabolic disorders see (Steenblock et al, 2021). With regard to cognitive functions, our study’s findings on females’ reading time scores are consistent with earlier studies that have found an association between COVID-19 infection and impairment in information processing speed (Almeria, Cejudo, Sanz-Santos, Deus, & Krupinski, 2023; Ferrucci et al, 2021; Flegr & Latifi, 2023). However, unlike these studies, we found a significant negative correlation between COVID-19 infection and females’ reaction times in the Stroop test, indicating improved reaction times compared to those who were not infected.…”

“…Based on the traditional Cohen classification, most of the observed effects fall into the “weak” category, and only those with a Tau greater than 0.26 could be classified as “moderate.” However, it is critical to remember that the impacts of biological factors on performance and personality tend to be relatively modest. For instance, a similar study investigating the effects of COVID-19 and vaccination on performance and health in a larger but more heterogeneous online population found effects to be typically 3-5 times weaker, albeit still significant due to the large sample size (Flegr & Latifi, 2023). The generally small effect sizes of biological factors on, e.g., cognitive performance observed in cross-sectional studies within the human population can be attributed to the presence of numerous confounding variables beyond the primary independent variable (in this case, SARS-CoV-2 infection).…”