Impact of COVID-19 restrictions on childhood allergic sensitization: a three-phase comparative study

This study aimed to investigate the influence of COVID-19 restrictions on the prevalence of allergen sensitivity in children. This study included patients who underwent allergen testing at our hospital before deregulation, after deregulation, and during the corresponding period in 2021. Changes in allergen-specific IgE (sIgE) positivity, IgE levels, and polysensitization were analyzed to to evaluate the impact of lifting COVID-19 restrictions on allergic diseases. Compared with those in the prederegulation period and the same period in 2021, the number of children with allergies visiting the hospital decreased following deregulation. The rate of allergen positivity was lower after deregulation than before but higher than that during the same period in 2021. After deregulation, allergen sIgE levels were lower than those before deregulation but higher than those in the same period in 2021. The correlation between milk and beef sensitivity was weaker after deregulation than before but stronger than that in 2021 (R values: 0.814, 0.854, and 0.104, respectively). During the period of COVID-19 restrictions, lower levels of allergic disease activity were observed compared to the pre-deregulation period. However, following the deregulation and the subsequent surge in COVID-19 infections, levels of allergic disease activity appeared to increase relative to the same observation period in 2021.