Effect of the COVID-19 Lockdown on Asthma Biological Rhythms

Abstract

Asthma has a striking temporal character, in which time-of-day, patient age, and season each influence disease activity. The extent to which rhythms in asthma activity reflect exposure to specific disease triggers remains unclear. In this study, we examined how virus mitigation strategies enacted during the COVID-19 pandemic (“lockdown measures”) affected rhythms in asthma clinical activity in children. To this end, we retrospectively analyzed asthma clinical presentations in children aged <18 years to our regional academic medical center, comparing 4 years of medical records prior to COVID-19 lockdown measures with the 12 months immediately after the institution of such measures. We correlated these data to positive viral test results, febrile seizures, and allergic clinical surrogates (allergic reaction visits and Emergency Department [ED] antihistamine prescriptions, respectively) over the same time frame. In the 12 months following the institution of the COVID-19 lockdown, positivity rates for common respiratory viruses dropped by 70.2% and ED visits for asthma among children dropped by 62% compared to pre-COVID years. Lockdown suppressed seasonal variation in positive viral tests and asthma ED visits, while diurnal rhythms in asthma visits were unchanged. Asthma seasonality correlated most strongly with rhinovirus positivity both before and after the institution of COVID lockdown measures. Altogether, our data support a causal role for viruses in driving seasonal variability in asthma exacerbations in children.

Age-dependent rebound in asthma exacerbations after COVID-19 lockdown

“…The pre-lockdown period exhibited the traditional seasonal pattern in viral detection, whereas the lockdown interval demonstrated greatly reduced instances of virus detection as previously described. 1,2,9 The post-lockdown period demonstrated a resurgence in instances of respiratory virus detection, with a shift in the cumulative seasonal peak to the summer months (Fig 1, A). We observed similar differences between rates of viral positivity, defined as the percentage of positive tests (Fig 1 , B).…”

“…However, we did not detect a signal for this in a recent analysis of pediatric asthma exacerbations, although in another study, patient avoidance proved to be a minor factor for asthma in the ED setting. 7,9 Even if present, patient avoidance would bias us toward underestimating the observed rebound in viruses and airway disease exacerbations during the post-lockdown period. Finally, patients made highly individualistic and fluid choices in their adherence to COVID-19 precautions, and as a result, demarcating periods of time as either lockdown or postlockdown periods is inherently inexact.…”

“…[2][3][4] In concert, the activity of several inflammatory airway diseases, especially asthma and chronic obstructive pulmonary disease (COPD), diminished. 1,[5][6][7][8][9][10][11] By the spring of 2021, however, COVID-19 vaccines became widely available, attitudes toward preventative measures became less strict, and common viruses began to uptrend by May 2021. [12][13][14] Here, we report how viral rebound during the relaxation of COVID-19 precautions affected asthma and COPD exacerbations.…”

The prevalence of childhood asthma: interpreting falling rates in the context of shifting measurement and the COVID-19 pandemic

“…A marked decrease in paediatric respiratory infections due to non-COVID-19 viruses was observed starting in March 2020, following the widespread implementation of societal lockdowns [ 21 ▪ ]. With fewer rhinovirus infections in the immediate postlockdown period, the overall burden of rhinovirus-associated wheezing illnesses is likely to have been lower for children who were less than 3 years old at the time.…”

“…With fewer rhinovirus infections in the immediate postlockdown period, the overall burden of rhinovirus-associated wheezing illnesses is likely to have been lower for children who were less than 3 years old at the time. However, although influenza and RSV rates remained low during the first autumn and winter following lockdown, rhinovirus infections rebounded to prepandemic levels by the fall of 2020 [ 21 ▪ , 25 ▪ ]. The rapid return to normal rhinovirus infection levels, likely related to decreased susceptibility of rhinoviruses to certain infection prevention measures (i.e.…”