Substantial decrease noted in severe respiratory illness during first 2 years of pandemic


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Compared to the 3 years prior to the pandemic, children with medically complex conditions and otherwise healthy children saw decreases in severe non-COVID respiratory illnesses in 2020 and 2021, the authors of a study yesterday note in JAMA Network Open.

The cross-sectional study, based on 139,078 respiratory hospitalizations in Canada, shows that the mitigation efforts used during the first several months of COVID-19 likely prevented serious outcomes from respiratory illness complications, including hospitalizations, intensive care unit (ICU) admissions, and death.

Medical complexity and kids without it

Previous studies have shown that the COVID-19 prevention strategies used by many countries were associated with substantial reductions in circulating levels of respiratory syncytial virus and influenza. This is one of the first studies, however, to examine severe respiratory illness occurrence among children with medical complexity (CMC) and without medical complexity (non-CMC).

CMC include those with neurologic impairment (NI), which accounts for 28% of all Canadian CMC, children with congenital heart diseases, cystic fibrosis, and sickle cell disease.

The study was based on hospitalizations tracked in the Canadian Institutes for Health Information Discharge Abstract Database (CIHI-DAD) from April 1, 2017, to February 28, 2022, for all children 18 years and under, excluding residents of Quebec.

A CMC hospitalization was defined as a child with any complex chronic condition or NI diagnosis code recorded in the 5 years before the index hospitalization, the authors said. The prepandemic period was April 1, 2017 through March 1, 2020, and the pandemic phase of the study was April 2020 through February 2022.

The researchers limited capture of data on COVID-19 diagnoses to children who had an additional respiratory illness, such as pneumonia. "Although we may have missed some cases that were misclassified, at the time, 43.2% of Canadian children admitted to hospital with SARS-CoV-2 infections were not admitted because of COVID-19 (they typically had incidental SARS-CoV-2 infection detected during universal screening at hospital admission)," they wrote.

Dramatic drop in deaths

In total there were 139,078 respiratory hospitalizations (29,461 for CMC and 109,617 for non-CMC) from March 1, 2017, to February 28, 2022, and children ages 2 and younger accounted for 34.8% of CMC hospitalizations and 51.7% of non-CMC hospitalizations.

During the first year of the pandemic, CMC annual respiratory hospitalization rates drops from 1,385.6 per 10,000 hospitalizations per year to 611.4 per 10,000 CMC, an annual rate difference of 774.2 per 10 000 CMC and a rate ratio (RR) of 0.44 (95% confidence interval [CI], 0.42 to 0.46).

Among non-CMC, the drop was even greater, from 52.9 per 10,000 in the prepandemic years to 9.7 per 10,000 in 2020.

Respiratory ICU admissions for CMC decreased from 441.8 per 10,000 prepandemic to 248.9 per 10,000 (RR, 0.56 [95% CI, 0.53 to 0.59]) in 2020 and 292.7 per 10,000 (RR, 0.66 [95% CI, 0.63-0.70]) in 2021.

Among CMC, compared with prepandemic (33.8 per 10 000), mortality during respiratory hospitalizations decreased in both 2020 (21.2 per 10 000; RR, 0.63 [95% CI, 0.51 to 0.77]) and 2021 (24.2 per 10,000; RR, 0.72 [95% CI, 0.59 to 0.87])

Taken together, this degree of serious respiratory illness reduction over the 2 pandemic years corresponds to a decrease in over 44,500 hospitalizations among Canadian children.

"Taken together, this degree of serious respiratory illness reduction over the 2 pandemic years corresponds to a decrease in over 44,500 hospitalizations among Canadian children (7409 for CMC, 37 448 for non-CMC)," the authors wrote.

In addition, the data reflected more than 4,200 fewer ICU admissions (1,829 for CMC, 2,460 for non-CMC) and a decrease of 119 CMC in-hospital deaths.

"The decline observed among CMC is clinically important and was associated with decreased mortality," the authors noted.

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