Coronavirus: the amount of particles or “viral load” affects severity

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Professor Lucy Yardley of the University of Bristol sounded the alarm today, saying that the evidence shows that

Professor Lucy Yardley of the University of Bristol sounded the alarm today, saying there is evidence that “viral load” plays a big part in how a sick person will get sick

People exposed to a higher dose of coronavirus are more likely to get seriously ill, warned a scientist in the SAGE number 10 panel.

Professor Lucy Yardley of the University of Bristol sounded the alarm today, saying there is evidence that “viral load” plays a big role in how a sick person becomes.

She said this explains why so many healthcare workers – who come into face-to-face contact with critically ill patients – have been victims of the disease and should be factored into the ministers’ locking out strategy.

Having a high viral load – the number of virus particles they are first infected with – gives the bug a “quick start.”

It also increases a patient’s risk of overloading their immune system in the battle against COVID-19.

This means that someone infected indirectly by touching a door handle may end up with milder symptoms than someone who inhales an infected person’s cough.

Professor Yardley warned that the virus could be more deadly if it spread between families in the same house due to prolonged close contact. She did not mention whether the colleagues would be at risk – but they would also come into contact with each other in the office without strict rules of social distancing.

The repeated exposure to a high viral load explains why so many health professionals have been victims of the disease. Pictured: PPE staff treating a COVID-19 patient at the Royal Papworth Hospital in Cambridge

Repeated exposure to a high viral load explains why so many health professionals have been victims of the disease. Pictured: PPE staff treating a COVID-19 patient at the Royal Papworth Hospital in Cambridge

This morning she told BBC Radio 4 Today: “There is a lot of evidence to suggest that the more you are exposed to a virus while you are infected, the higher the risk that you will become infected but also you may be more seriously ill.

“And I think that is what led to the recommendations, of course, for a lot of protective gear for people exposed to a lot of the virus in hospitals and now in nursing homes.

WHY DOES A HIGHER VIRAL LOAD INCREASE SYMPTOMS?

Anyone who gets COVID-19 will develop huge amounts of the virus inside their body, but people will first be infected with different amounts of it – known as the viral load.

A person who breathes the cough of a critically ill patient at the height of the fever, for example, will be exposed to more virus than someone who touches a doorknob who coughed two days ago.

Most symptoms of the coronavirus are caused by the immune reaction that is triggered when the virus is found in the body.

In order to destroy viruses, the body increases its internal temperature to kill them, causing fever, and uses huge amounts of calories to send immune cells into the bloodstream to attack viruses, causing fatigue and pain. .

Being exposed to a smaller number of viruses at first may mean that the body can start with a smaller immune response.

More viruses, however, would mean the need for a larger reaction that could produce more severe symptoms and increase the risk of developing sepsis later in the disease.

“But we argue that it probably needs to be applied more at home, where people take care of most people with coronavirus.

“This has been observed mainly in places like hospitals – but in fact, you see very bad families.

“People worry, maybe too much, about passing someone on the street without a mask [but] unless they cough in your face, which would be dangerous, it’s probably not very risky.

“Whereas having to spend considerable time in the vicinity of someone is a particularly risky situation. “

The professor of health psychology said there are ways to effectively prevent getting the virus even if someone in the same house is infected.

She added, “You really want to isolate yourself from them as much as possible, so if you have more than one room in the house, you really need them to be in a room completely alone and not going out in the kitchen. . .

“If you can have different places to wash and so on, that would be nice. If you can’t, you should immediately clean all faucets and shared surfaces very well [after] they used them, good ventilation in the house so that the germs that circulate go into the open air.

“There are a number of things you can and should do. People tend to think it’s inevitable that we get it … you can really reduce the number of infections in the household by doing all of this. “

“If there is a safe place where you can go to another house, if you know someone else who has a room that you can safely use, that would be very helpful.”

Missing heroes: in the photo are the faces of some of the frontline health and social services workers who died from the coronavirus during the pandemic

Missing heroes: in the photo are the faces of some of the frontline health and social services workers who died from the coronavirus during the pandemic

How many doctors have died from coronavirus?

The government reports that 49 NHS officers died from COVID-19, but it is clear that many more have died.

The figures suggest that at least 171 frontline health workers have been affected by the disease.

They include at least 27 doctors and about 100 nurses and caregivers, according to Nursing Notes, a website dedicated to the well-being of medical staff.

They include at least 27 doctors and about 100 nurses and caregivers, according to Nursing Notes, a website dedicated to the well-being of medical staff.

But the real figure is probably higher because not all deaths will be in the public domain and not all victims will have been tested for the disease.

And official NHS data last month revealed that one in three frontline workers tested positive for the disease.

Out of 17,000 samples taken from key workers on April 14, 5,733 people were positive, a rate of 33%.

He suggests the infection was rife in UK hospitals – where staff have always had difficulty accessing protective equipment – at the height of the crisis.

In Italy, at least 101 doctors died from the coronavirus, including 80 doctors and 21 nurses.

Two additional nurses have committed suicide since the epidemic.

Professor Yardley presented these recommendations to ministers in a commentary which has been submitted to the prestigious British Medical Journal for publication this evening.

The report also recommends that the government use positive messages to encourage Britons to adhere to social distancing when restrictions are relaxed, as opposed to a fear-motivated campaign.

The way viruses make people sick is to multiply quickly once inside the body and to accumulate in such large numbers that the body takes weeks to destroy them all.

This process is inevitable once someone has caught an infection, but it is possible that people will get sick first with only a small dose of the virus.

This can, in theory, allow the “army” of their body’s immune system to cope and repel early infection.

In fact, for the coronavirus, it seems likely that a large majority of patients will get sick under these circumstances and take an unusually long time to notice that they are sick.

For this reason, people appear to spread COVID-19 more widely than they would if they had a more serious illness.

Dr. Michael Skinner, also of Imperial College, said that if someone started with a massive amount of virus, it could overload their immune system.

The virus would take a “quick start” under such circumstances, he suggested, because it could develop faster before the body had time to react.

Dr. Skinner said, “We need to be more concerned about situations where someone is getting a massive dose of virus (we don’t have data on their size, but the body fluids of those infected with other viruses can contain one million, and up to one hundred million viruses per ml), in particular by inhalation. “

He said it would be a “rare occurrence” and that people outside the hospital staff were unlikely to be exposed to massive amounts of the virus.

Scientists do not believe that the viral load of people will increase if they are exposed to more infected people after their first illness.

They also don’t think there is little chance that the virus will accumulate from multiple sources before it reaches a threshold that makes them sick.

Dr. Skinner added that if someone is infected with a large viral load: “The virus gets a massive start, leading to a massive immune response, which will be difficult to control the virus to allow time for acquired immunity trigger while it is causing considerable inflammation and a cytokine storm at the same time. “

Uncontrollable inflammation (swelling) caused by the body’s immune system can be devastating and cause life-threatening conditions such as kidney failure or sepsis.

It is known to be a contributing factor to serious illness and death in COVID-19 patients.

And a “cytokine storm” occurs when white blood cells go haywire and can cause kidney or lung failure and death.

Professor Jonathan Ball, expert in virology at the University of Nottingham, said: “It is possible that people with pneumonia who have a higher viral load develop more serious disease, but the development of the disease is complex and no doubt many factors will have an impact. “

A HIGHER VIRAL LOAD LINKED TO MORE SERIOUS SYMPTOMS, A STUDY IN LANCET PURPOSES

A scientific article published in the British medical journal The Lancet in March suggested that a high viral load was linked to more severe symptoms.

The study examined 76 patients with coronavirus in Nanchang, China, who had been admitted to hospital and tested positive for COVID-19.

The researchers, led by Dr. Wei Zhang, wrote, “The average [average] viral load in severe cases was about 60 times higher than that in mild cases, suggesting that a higher viral load may be associated with serious clinical outcomes. “

At least 80% of coronavirus patients are thought to have only a mild cold-like illness, while some may develop more serious breathing problems.

The most seriously ill patients end up in the hospital with pneumonia and in the intensive care units have a survival rate of around 50%.

Dr. Wei and colleagues added that a high viral load also appeared to increase the risk of serious illness in patients with SARS, a similar virus that caused an epidemic in 2002.

They wrote, “This discovery suggests that the viral load of SARS-CoV-2 may be a useful marker for assessing the severity and prognosis of the disease. “

Oxford University researchers agreed that studies seem to show that a higher viral load worsens symptoms of coronaviruses, but there was no solid evidence.

An analysis from the Nuffield Department of Health Sciences in Primary Care reads: “The evidence suggests an association of the viral dose with the severity of the disease.

“However, the evidence for the relationship is limited by the poor quality of many studies.”

To avoid getting infected with a higher viral load, the best thing people can do is stay away from others who are or might be sick, said Dr. Wendy Barclay.

The viral load would be higher if someone coughed directly into your face than if it were two meters away and the viruses were dispersed in the air.

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