Experts explain that Covid-19 deaths are often caused by pneumonia, while explaining the viral mechanism that causes pneumonia in the elderly and people with underlying disease.
Most people with Covid-19 have only mild symptoms. The World Health Organization says about 80% of patients recover without specialized treatment. But about 1 in 6 is seriously ill and “has trouble breathing”.
Professor John Wilson, president of the Australasian Royal Physician University and a respiratory specialist, told Guardian Australia that people with Covid-19 became serious cases mostly from pneumonia.
6% of Covid-19 cases were hospitalized with severe symptoms
Mr. Wilson said people infected with Covid-19 can generally be divided into four groups.
Less serious are viral infections but “below clinical symptoms”.
Next are infections in the upper part of the airways, which can lead to fever, cough and mild symptoms such as headache or conjunctivitis. These people can still infect the virus without knowing it.
The next group, the largest group, includes people with flu-like symptoms that prevent them from working, and are likely to go to the clinic.
The remaining group will have severe symptoms, including pneumonia.
“In Wuhan, among those who are positive and visiting, 6% have severe symptoms,” Wilson told the Guardian.
Pneumonia caused the death of Covid-19 infection
When people infected with Covid-19 have a cough, fever, it is the result of infection of the respiratory tract branches. The mucosa of the airways is damaged, causing inflammation. That makes nerves in the airway mucosa irritated. Even a speck of dust can make a person cough.
“But if the situation worsens, the inflammation goes deeper, going through the lining of the airway, entering the alveoli, which is the gas exchange point at the end of the airway,” Wilson said.
“Once those spots are infected with the virus, they respond by secreting fluids … at the bottom of the lungs,” he added.
The fluid causes the air sacs to become inflamed, leading to pneumonia. “It is often the cause of death when pneumonia becomes severe.”
There is no way to prevent pneumonia in Covid-19 patients
Professor Christine Jenkins, president of the Australian Lung Foundation and leading respiratory physician, told Guardian Australia: “Unfortunately, we currently have no way to prevent pneumonia,” although many drugs are to be tested.
“There is currently no clear treatment regimen other than supportive treatment, which is the treatment of intensive care patients … we support mechanical ventilation, maintaining high oxygen levels until the lungs of the patients can resume normal functioning and they recover, ”said Jenkins.
Professor Wilson said patients with viral pneumonia are also at risk of secondary infection, so they will also be treated with antiviral drugs and antibiotics.
“In some cases, this is not enough,” he said of the current Covid-19 epidemic. “Pneumonia does not subside and patients do not recover.”
Covid-19 pneumonia affects the entire lung
Professor Jenkins said SARS-CoV-2 pneumonia is different from other pneumonia cases that often require hospitalization.
“Most of the pneumonia we know and take patients into hospital is caused by bacteria, and can be treated with antibiotics,” she said.
Wilson said there was evidence that Covid-19 pneumonia could be particularly serious. Pneumonia in Covid-19 infections usually affects the entire lung, rather than just small portions of the lung.
“Once we have pneumonia, and if it is related to the alveoli, the body’s first reaction will be to try to kill the virus and limit the replication,” he said.
But Wilson said that initial response mechanism may be impaired in some groups of patients, including patients with heart disease, lung disease, diabetes, or in elderly patients.
Jenkins said that people who are at high risk of pneumonia are over 65, people with underlying medical conditions such as diabetes, cancer, chronic diseases affecting the lungs, heart, kidneys, liver, smokers, or children under 12 months old.
“Age is a major predictor of the risk of dying from pneumonia. Pneumonia is always serious for the elderly, and in fact it was a major cause of death in the elderly. But now we have many treatments for pneumonia, ”she said.
“The risk of pneumonia increases with age, regardless of whether you are healthy or physically active. This is because the immune system weakens naturally with age, making it harder to fight infections and illnesses. ”