A comprehensive review into what we know about COVID-19 and the way it
functions suggests the virus has a unique infectious profile, which explains
why it can be so hard to treat and why some people experience so-called
"long COVID," struggling with significant health issues months after
infection.
There is growing evidence that the virus infects both the upper and lower
respiratory tracts—unlike "low pathogenic" human coronavirus sub-species,
which typically settle in the upper respiratory tract and cause cold-like
symptoms, or "high pathogenic" viruses such as those that cause SARS and
ARDS, which typically settle in the lower respiratory tract.
Additionally, more frequent multi-organ impacts, blood clots, and an unusual
immune-inflammatory response not commonly associated with other similar
viruses mean that COVID-19 has evolved a uniquely challenging set of
characteristics.
While animal and experimental models imply an overly aggressive
immune-inflammation response is a key driver, it seems things work
differently in humans: Although inflammation is a factor, it is a unique
disregulation of the immune response that causes our bodies to mismanage the
way they fight the virus.
This may explain why some people experience "long COVID" and suffer severe
lung damage after infection.
Ignacio Martin-Loeches, Clinical Professor in Trinity College Dublin's
School of Medicine, and Consultant in Intensive Care Medicine at St James's
Hospital, is a co-author of the review just published in leading medical
journal The Lancet. He said:
"The emergence of severe acute respiratory syndrome coronavirus two
(SARS-CoV-2), which causes COVID-19, has resulted in a health crisis not
witnessed since the 1918 Spanish flu pandemic. Tragically, millions around
the world have died already.
"Despite international focus on the virus, we are only just beginning to
understand its intricacies. Based on growing evidence we propose that
COVID-19 should be perceived as a new entity with a previously unknown
infectious profile. It has its own characteristics and distinct
pathophysiology and we need to be aware of this when treating people.
"That doesn't mean we should abandon existing best-practice treatments that
are based on our knowledge of other human coronaviruses, but an unbiased,
gradual assembly of the key COVID-19 puzzle pieces for different patient
cohorts—based on sex, age, ethnicity, pre-existing comorbidities—is what is
needed to modify the existing treatment guidelines, subsequently providing
the most adequate care to COVID-19 patients."
The review article was produced by the European Group on Immunology of
Sepsis (EGIS) in which Professor Martin-Loeches is one of the funding
members. EGIS is a multidisciplinary group of scientists and doctors with
special interest in severe infection in patients admitted to ICU.
Reference:
Marcin F Osuchowski et al, The COVID-19 puzzle: deciphering pathophysiology
and phenotypes of a new disease entity, The Lancet Respiratory Medicine
(2021). DOI:
10.1016/S2213-2600(21)00218-6