Study shows link between global warming, deaths from respiratory illness

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A mathematical modeling study today from the Barcelona Institute for Global Health (ISGlobal) suggests that the risk of hospital death from respiratory illness is higher in warmer, summer months, which may have implications for how hospitals will need to adjust to climate change.

The study is published in The Lancet Regional Health - Europe and is based on data on ambient temperature and in-hospital mortality from respiratory diseases in Madrid and Barcelona from 2006 through 2019.

In Spain, respiratory illness has a winter peak and a summer low. But, the authors wrote, there is little known about seasonal variation in inpatient mortality, a surrogate for hospital performance in relation to severe respiratory events. The study used data on daily hospital admissions, weather, and common air pollutants to compare ambient temperature associations and in-patient mortality.

Deaths peaked in August

The investigators found that summer temperatures accounted for 16.2% and 22.3% of overall fatal hospitalizations from respiratory diseases in Madrid and Barcelona, respectively. Though hospital admissions for respiratory illnesses were highest in cold weather months, case-fatality rates (CFR) peaked in August.

"We saw that the higher CFR in the warm season was mainly driven by pneumonia, acute bronchitis and bronchiolitis, COPD, and, especially, respiratory failure," the authors wrote.

The authors said this finding could be consequential in the face of warming daily temperatures.

The increase in acute respiratory outcomes during heat is more related to the aggravation of chronic and infectious respiratory diseases than to the spread of new respiratory infection.

"This suggests that the increase in acute respiratory outcomes during heat is more related to the aggravation of chronic and infectious respiratory diseases than to the spread of new respiratory infections, which usually take several days to cause symptoms," said Hicham Achebak, PhD, first author of the study in an ISGLOBAL press release. "Unless effective adaptation measures are taken in hospital facilities, climate warming could exacerbate the burden of inpatient mortality from respiratory diseases during the warm season."

CDC to expand testing for respiratory viruses at airports

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Air traveler COVID testing
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The Centers for Disease Control and Prevention (CDC) announced yesterday that it will expand testing of international air travelers beyond COVID-19 to provide early detection of other respiratory viruses.

The Traveler-based Genomic Surveillance (TGS) program, which covers flights from more than 135 countries and has been implemented at seven airports nationwide, collects and analyzes nasal samples from arriving international travelers on a voluntary basis, along with aircraft wastewater samples, to test for and track new SARS-CoV-2 variants. The CDC said TGS recently provided early detection of the BA.2.86 variant in a traveler from Japan.

Under a pilot program that will last several months, TGS will expand testing to analyze samples for flu, respiratory syncytial virus (RSV), and other select respiratory viruses. Samples that test positive for these viruses will be sequenced and uploaded to public databases.

"The expansion of the Traveler-based Genomic Surveillance program to flu, RSV, and other pathogens is essential as we head into fall respiratory season," Cindy Friedman, chief of the CDC's Travelers' Health Branch, said in a press release. "The TGS program, which began during the COVID-19 pandemic, acted as an early-warning system to detect new and rare variants of the SARS-CoV-2 virus and will do the same for other respiratory viruses going forward."

As of September 2023, TGS has enrolled more than 360,000 air travelers.

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