September 1, 2021 8:49:38 am
A build-up of coronavirus in the lungs is likely behind the steep mortality rates seen in the pandemic, a new study has found. The results contrast with previous suspicions that simultaneous infections, such as bacterial pneumonia or overreaction of the body’s immune defence system, played major roles in heightened risk of death, according to a media release from NYU Grossman School of Medicine, whose researchers led the study, published in the journal Nature Microbiology.
The study found that people who died of Covid-19 had on average 10 times the amount of virus in their lower airways as did severely ill patients who survived their illness. Meanwhile, the investigators found no evidence implicating a secondary bacterial infection as the cause of the deaths, although they cautioned that this may be due to the frequent course of antibiotics given to critically ill patients.
“Our findings suggest that the body’s failure to cope with the large numbers of virus infecting the lungs is largely responsible for Covid-19 deaths in the pandemic,” the release quoted study lead author Imran Sulaiman as saying.
The study was designed to clarify the role of secondary infections, viral load, and immune cell populations in Covid-19 mortality. The release quoted Dr Sulaiman as saying the investigation provides the most detailed survey of the lower airway environment in patients with coronavirus.
The researchers collected bacterial and fungal samples from the lungs of 589 men and women hospitalised in NYU Langone facilities. All required ventilation. For a subset of 142 who also received a bronchoscopy procedure to clear their air passages, the study analysed the amount of virus in their lower airways.
The study found that those who died had on average 50% lower production of a type of immune chemical that targets the coronavirus, compared with patients who survived.
Source: NYU Langone