Why loss of smell occurs in long COVID-19

Small respiratory droplets, the majority of which are generated in the lungs, are substantially less infectious in children than in adults. Findings like these come from a study led by researchers at the University of Gottingen Medical Center and the Max Planck Institutes for Dynamics and Self-Organization (MPI-DS) and Chemistry (UMG).

Using data from 132 persons of varying ages, the researchers looked into the quantities of aerosol particles and droplets released during breathing, speech, singing, and yelling. The results shed light on how illnesses like Covid-19 can be stopped in its tracks.

Particles in the air may easily spread an infectious illness from one person to another. Depending on where they came from in the respiratory system, the size of these aerosol particles might range widely. PM5 refers to particles that are fewer than five microns in size and are mostly formed in the lungs. In contrast, the upper respiratory tract generates larger particles.

Measurements demonstrated that children breath much fewer PM2.5 particles than adults. “Particles smaller than five microns in size tend to accumulate with age, whereas their relative scarcity is most pronounced in young people. Therefore, if an illness is confined to the lower respiratory tract, it is far more likely to spread when an adult contracts it “Mohsen Bagheri, head of a research group at the Max Planck Institute for Dynamics of Systems (MPI-DS) and the paper’s primary author, explains.

Of particular note, the study found that both toddlers and adults are equally responsible for spreading bigger particles that start in the neck. Exhaled particle concentration was not related to sex, body mass index, physical activity level, or smoking status.

The researchers gathered information from 132 healthy individuals in this extensive investigation. Children and teenagers (aged 5-18) for whom very little information is available were also included in the research. Exhaled particles of all sizes (from 0.1 micrometres to 0.25 millimetres) were measured using a battery of devices set up in a dust-free environment. Participants spent 20 minutes engaging in a variety of vocalisation tasks, including singing, speaking, and yelling. Prof. Simone Scheithauer of the UMG’s Division of Infection Control and Infectious Diseases writes, “Vocalization and age are revealed to be independent risk factors for particle generation.”

The majority of the pathogen-carrying volume is really found in the bigger particles that aren’t present in human droplets and aerosols. According to MPI-DS director Eberhard Bodenschatz: “If the virus largely lives in the upper respiratory tract, the big particles are the far major transmitter of the illness.”

The location of the infectious particle in the respiratory system should be taken into account when determining the level of protection needed, he says. The current Omicron version of the coronavirus, for instance, appears to be localised mainly to the upper respiratory tract, thus even basic filtering face masks are a wonderful defence.