COVID-19 infection detected in breath tests

Date:
February 22, 2022
Source:
University of Gothenburg
Summary:
Traces of the SARS-CoV-2 coronavirus that causes COVID-19 can be
detected in microscopically small fluid droplets exhaled during
a very short time span, according to a new study.



FULL STORY ========================================================================== Traces of the SARS-CoV-2 coronavirus that causes COVID-19 can be detected
in microscopically small fluid droplets exhaled during a very short
time span.

This is the finding of a new study from the University of Gothenburg. The measurement was carried out primarily with an advanced research instrument developed by the publishing research team.


==========================================================================
The findings have now been published in the journal Influenza and
Other Respiratory Viruses. The measurements were made with the research instrument Particles in Exhaled Air (PExA), developed at Occupational
and Environmental Medicine at Sahlgrenska Academy, and with a smaller
handheld instrument called the Breath Explor (BE).

Infection spread with exhaled air is well known, but now the researchers
show that a few breaths are sufficient for detecting traces of viruses
in microscopically small fluid droplets (i.e. particles) exhaled from
small airways, at least early in the course of COVID-19.

"We show that aerosol particles with the ribonucleic acid (RNA) virus can
be found early in the course of COVID-19. The particles we can detect
are very small-less than five micrometers in diameter-and we have here
managed to capture particles with RNA virus in just a few breaths," said
Emilia Viklund, a doctoral student in occupational and environmental
medicine and lead author of the study.

Affects in the small airways Of course, this immediately leads to
conjecture about possibly replacing unpleasant nasal swab tests with
convenient and easy breath tests. However, according to Professor
Anna-Carin Olin, the inventor of PExA, that would be extrapolating the
findings too far.



========================================================================== "Respiratory viruses such as SARS-CoV-2 are likely to be concentrated
mainly in the nose and throat, and it is easiest to take samples
from that mucous membrane to detect the infection," says Professor
Olin. "In contrast, the method of taking measurement in exhaled air
is a very promising way of studying how the virus affects the small
respiratory airways and how this effect changes during the course of
the disease. Among other things, we are working on studies of post-COVID conditions using this method." Emilia Viklund says, "Methods for studying aerosol particles can be a good way of complementing established methods
of measuring and monitoring COVID-19. In general, we can say that analysis
of exhaled air has great potential for studying the spread of infection
and where the virus is in the respiratory tract." Difficult to recruit
study subjects The idea of trying to measure viruses and signs of changes
in the small respiratory passages using PExA originated early in 2020,
when the pandemic was an established fact. One challenge has been
recruiting study subjects early in the course of the disease, despite
close collaboration with the research team of the study's co-author,
Professor Johan Westin, in the Department of Infectious Diseases.

In an initial small study involving only 10 subjects conducted in the
autumn of 2020, only one of the samples was positive. The researchers
believe this resulted from conducting measurements too late in the course
of the disease. In collaboration with Sahlgrenska University Hospital,
which allowed parallel measurement in connection with employees taking polymerase chain reaction (PCR) tests on the hospital grounds, the
study eventually evolved to include more subjects in an earlier stage
of the disease. These measurements were conducted in the spring of 2021
on medical professionals who had just submitted positive PCR samples
for COVID-19.



========================================================================== Three different techniques were used to collect the samples: 20 normal
breaths; a technique in which study subjects briefly hold their breath
after a very deep exhalation; and a technique in which the study subject coughed three times into the instrument.

Extremely small samples The research shows unsurprisingly that coughing generated the most positive breath samples collected with PExA (8 of
25), followed by deep breathing (3 of 25) and regular breathing (2 of
25). Two positive aerosol samples from normal respiration were also
generated when collected with the instrument Breath Explor, although
these came from individuals who were separate from the PExA findings
with normal respiration.

"The quantity of aerosol particles we needed for the test was about one
10- millionth of the amount from nasal swab samples needed to detect viral
RNA in regular respiration with PCR analysis," says Anna-Carin Olin. "The findings from the deep-breathing maneuver came as a surprise, the amount
of sample is minute. Fluid droplets that one exhales after deep breathing
form largely in the small airways, where it is known that the virus can
cause great damage. As a result, it would be exciting to further study
the findings in the exhaled air in relation to disease progression."
Continued research The Alpha viral variant dominated when surveys were conducted, which caused infection that often extended farther down into
the lungs compared with the now dominant Omicron variant. New studies
underway will help explain how the complement system in small respiratory passages is activated, whether the response looks different when viruses change, and the long-term effects on small respiratory passages in the
case of post-COVID syndrome.

Emilia Viklund is essentially a biomedical analyst, focusing on
physiological investigations. The study now becomes part of her thesis,
which she is scheduled to defend in early summer. The other contributing
papers also involve measuring small particles with PExA and other
methods of lung function measurements, but in that case in connection
with smoking and asthma.

========================================================================== Story Source: Materials provided by University_of_Gothenburg. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Emilia Viklund, Spela Kokelj, Per Larsson, Rickard Norde'n, Maria
Andersson, Olof Beck, Johan Westin, Anna‐Carin Olin. Severe
acute respiratory syndrome coronavirus 2 can be detected in
exhaled aerosol sampled during a few minutes of breathing or
coughing. Influenza and Other Respiratory Viruses, 2022; DOI:
10.1111/irv.12964 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220222121242.htm

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