The problem with such a fast and widespread pandemic as the novel
coronavirus is that scientists and doctors only understand the virus and the
disease it causes while in a state of flux. Knowledge changes almost daily and
it's often disseminated through hundreds of
preliminary scientific reports that doctors on
the ground might not have time to scour, busy as they are saving lives.
Some experts ponder whether scientists are
going too fast in the well-intentioned race to understand the
pandemic, causing more confusion than anything else.
Understanding
COVID-19, an 'unknown' disease with multiple faces
·
Half of those infected don't
develop symptoms, but are a vector of contagion
·
Most patients have only mild
symptoms
·
In severe patients it is not the
virus that kills, it is an uncontrolled reaction of the immune system that can
damage most vital organs, a cytokine storm
·
It's not known what makes that
some patients, regardless of their age, develop severe symptoms
·
The virus can attack the nervous
system. In some cases respiratory failure is related to neurological failure,
not pneumonia
·
It's not certain when recovered
patients stop being contagious
·
There are doubts about how long
immunity lasts after the disease
This constantly changing information plays a part in why we have
been hearing different advice, sometimes contradictory, from the authorities,
whether it be the convenience of using face masks or how to identify first
symptoms.
Some
still say "it's just a little flu" in
the face of evidence that demonstrates it is a deadly public health nightmare.
At the beginning of the epidemic we were told that cough and fever
were the unequivocal signs that we could have contracted COVID-19. Now we know
that the disease can cause a wide variety of symptoms and even no symptoms at
all.
It is believed that about 50% of infected patients are
asymptomatic - which has been one of the main factors in the light speed spread
of the novel coronavirus.
Many precise details about the disease remain pretty much unknown.
Doctors have learned to fight COVID-19 almost on a case by case basis even if
now protocols are improving.
Here are some leads, given to Euronews by doctors working on the
frontline, to better understand the disease, and why it is so dangerous for the
population at risk and our health systems.
WHAT WE KNOW
AND DON'T KNOW ABOUT THE COVID-19 CORONAVIRUS
HOW DOES COVID-19 HAPPEN?
Roger
Paredes, Head of the Infectious Diseases Section at Germans
Trias i Pujol Hospital, near Barcelona, tells Euronews that there are three
different stages of the infection for people developing COVID-19 symptoms:
·
The viral phase: when the virus replicates very quickly within the
respiratory system. Symptoms are similar to common flu and disappear
spontaneously after 6 to 10 days (roughly). It is the case for about 80% of the
patients.
·
The pulmonary phase: The other 20% of the patients might develop a pneumonia.
It’s a very specific type of pneumonia, attacking both lungs and causing
respiratory distress.
·
Severe phase: around 10% of the patients develop a “cytokine storm” an
uncontrolled inflammatory response of the immune system which is causing most
of the critical conditions and eventually, fatalities.
What's the real
killer?
Doctors on the ground report that severe cases don’t develop a
high “viral load” (concentration of virus) but a cytokine storm syndrome.
“The cytokine storm is a problem we face quite often in intensive
care” says Rafael Máñez, head of intensive care unit at Bellvitge Hospital,
also close to Barcelona. Other infections and even some drugs can trigger it.
“The problem is that we don’t have a treatment, neither against the virus nor
for the inflammatory response” Máñez tells Euronews. “We only have supportive
treatments, to protect the patient's vital organs”. Doctors use respirators, or
drugs to control blood pressure or corticoids to reduce inflammation.
Another lead is using drugs to block interlukin-6, a
pro-inflammatory cytokine produced by the immune system.
He says cytokine storms do happen during the flu season, but
patients admissions are gradual. “Due to the exceptional infection rates of
COVID-19 we get more patients than we can manage".
Máñez highlights a nuance in the consensus that having strong
defences are better to cope with the disease "you don’t need a strong
immune system but a balanced one” he states.
Dr. Paredes is leading a clinical study in cooperation with the US
National Institute of Health using remdesivir. It will take three years.
CLINICAL DRUG
TRIALS STARTING IN EUROPE INCLUDE POTENTIAL OF CHLOROQUINE TO TREAT CORONAVIRUS
CYTOKINE STORMS, AN OBSCURE SYNDROME
“The exact mechanisms of cytokine storms are pretty much unknown”
says Paredes. “The inflammatory response is a natural immune system reaction.
It’s necessary to repair cell damage. With normal pneumonia, germs damage the
pulmonary tissue and the immune system generates an inflammatory response to
stop it. The immune system ‘kills’ some cells to repair the damaged tissue.
What is happening now with coronavirus is that instead of sending a few cells
it’s sending tonnes of cells that generate an uncontrolled inflammatory
response, not only in lungs but can be widespread in the body”.
Indeed, there have been reports of
kidney, intestinal, or coronary damage.
“I have a young patient with a myocarditis (inflammation of the heart muscle)”
says Dr. Máñez.
It is believed that some of the patients experiencing intense
headaches could suffer encephalitis (inflammation of the brain).
Roger Paredes
Head of infectious diseases unit at Germans Trias i
Pujol Hospital
It is not known which factors predispose patients to develop the
syndrome. Regarding COVID-19, age is very significant. “The key is to
understand who are the most susceptible,” says Paredes “About 70% of our
patients are older than 70, and between 10% and 15% are younger than 60 years
old”.
Scientists believe genetics play a major role in the rare cases of
young patients developing the syndrome.
When people of any age suffer a cytokine storm, degradation is
really quick so it’s very important to identify the early signs, says Paredes.
According to Máñez, obesity can increase the chances of an
inflammatory response.
COVID-19 can attack central nervous system
Research and experience on the ground show that the SARS-CoV-2
virus can attack the central nervous system. Dr. Paredes reports some patients
in respiratory distress sometimes don’t feel the lack of oxygen or the
pneumonia.
He suspects some patients enter in respiratory distress precisely
because their nervous system is not managing to breathe properly. This has also
been reported in some preliminary papers.
The loss of smell and taste frequently reported could be also be linked to central
nervous system in some cases, according to Paredes.
Doctors around the world are reporting cases of neurological
manifestations suggesting the virus can breach into the central nervous system
like blood clots, dizziness, confusion or convulsions. The hospital of the
University of Brescia in Italy has opened a separate NeuroCovid unit to care
for patients with neurological conditions, The New York
Times reports.
A team from Wuhan,
the initial epicentre of the pandemic has issued a preliminary paper reporting
36.4% of the 214 patients studied developed different degrees of neurological
disorders. SARS-nCoV-2's predecessors SARS and MERS also could make their way
into our central nervous system.
All studies suggest these are rather rare cases but shouldn’t be
underestimated.
And after the
disease?
Even if scientists are beginning, gradually, to better understand
the disease, many questions remain about the perspectives for recovered
patients, like how long they will remain immune or the long term effects in
their organs.
According to Roger Paredes, released patients in Spain spend two
more weeks in quarantine at home before being tested again. It is currently
under discussion for how long theses patients remain a vector of contagion for
others. Current PCR tests are not 100% reliable to determine this. It will
depend on antibody tests in large population samples.
- Coronavirus: Antibody tests
'will be crucial' in determining when to lift lockdowns
While many governments are preparing their lockdown exit plans,
the European Centre for Disease Control (ECDC) has warned that rushing in could
lead to an upsurge and that, with the data in hand, no European country is
prepared to lift movement restrictions and social distancing measures due to
the difficulties in controlling cases.
"Before considering lifting any measures, member states
should ensure that improved systems of testing and surveillance of the
population and hospitals are in place to inform and monitor
escalation/dis-escalation strategies and to assess the epidemiological
consequences" says the ECDC.
Interestingly, despite scientific advances, staying home, soap and
hygiene are the main barriers to the virus so far. "We were not aware. We
had the feeling that with the knowledge we had this could not happen. With this
crisis we will realise that we are very vulnerable," summarises Dr. Rafael
Máñez.
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