Impact of mood and stress during COVID-19 lockdown on perceived immune fitness and the presence and severity of COVID-19 symptoms

Background: To address the rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) around the world, in the absence of a vaccine or adequate treatment for the 2019 coronavirus disease (COVID-19), many governments around the world enforced lockdown periods. While lockdowns are beneficial in reducing the spread of the virus, literature shows that lockdowns may also have a significant negative impact on mood, wellbeing, and health. In this context, we hypothesized that negative mood changes increase overall stress levels, which in turn has a negative effect on perceived immune fitness, expressed in a greater presence and severity of COVID-19 symptoms [1].

Objective: The aim of this study was to investigate the impact of mood and stress during COVID-19 lockdown on perceived immune fitness and reported COVID-19 symptoms.

Methods: An online retrospective survey was held among Dutch adults, to evaluate the first lockdown in The Netherlands [1]. Questions were answered for the period before the lockdown (15 January–14 March 2020) as well as for the lockdown period (15 March–11 May 2020). Mood was assessed via 1-item scales including “stress”, “anxiety”, “depression”, “fatigue”, “hostile”, “lonely” and “happy” [2]. Perceived immune fitness was assessed on a scale ranging from 0 (very poor) to 10 (excellent) [3]. The COVID-19 Symptoms Scale comprised the items sneezing, running nose, sore throat, cough, and malaise/feeling sick, high temperature (up to 38 Celsius), fever (38 Celsius and higher), shortness of breath, and chest pain [1]. The severity of each of the nine items could be rated as none (0), mild (1), moderate (2), or severe (3). The sum score of items served as COVID-19 symptom severity score, with a possible range from 0 (no complaints) to 27 (severe complaints). In addition, the presence of COVID-19 symptoms was calculated by counting the number of symptoms with a score > 0.

Assessments before and during COVID19 lockdown were compared using the Related Samples Wilcoxon Signed Rank Test. For each variable, difference scores (Δ, lockdown – before lockdown) were calculated. Pearson's correlations were calculated between difference scores.

Results: Data of 1415 Dutch adults (64% women, age range: 18 to 94 years old) were analyzed. During lockdown, all mood ratings, stress, and perceived immune fitness were significantly poorer compared to the period before lockdown (p<0.0001). The COVID-19 symptom severity score as significantly higher during the lockdown period (p=0.018), but no difference was found for the number of reported COVID-19 symptoms (p=0.256). Significant correlations were found between mood changes and Δ stress (r ranged from 0.334 to 0.557, all p<0.0001). The correlation between Δ stress and Δ perceived immune fitness was also significant (r=-0.310, p<0.0001). Finally, Δ perceived immune fitness correlated significantly with difference scores for the presence (r=-0.223, p<0.0001) and severity (r=-0.245, p<0.0001) of COVID-19 related symptoms.

Conclusions: The findings support the hypothesis that lockdown has a negative effect on mood and increases stress. This is reflected in poorer perceived immune fitness, which in turn is associated with a greater presence and severity of COVID-19 symptoms.