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Infectious Diseases

Updated 12 October 2020

Coronavirus research recap: Risk of PTSD, and why Covid differs from patient to patient

Recap of the latest coronavirus research and science: Are Covid-19 survivors at heightened risk of PTSD; and why Covid-19 differs so much from patient to patient.

LATEST SCIENCE AND RESEARCH

READ | Are Covid-19 survivors at heightened risk of PTSD?

A new research paper claims that people who have recovered from Covid-19 infection could experience lingering "brain fog", along with certain other symptoms – which could point toward post-traumatic stress disorder (PTSD).

These symptoms were allegedly also observed in the Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) outbreaks.

According to a news release, those who have recovered from a Covid-19 infection may experience headaches, anxiety, fatigue, sleep disruptions and difficulties with concentration.

Some patients fear that the virus may have caused permanent damage to the brain, but researchers say that such fears are probably unfounded.

Professor Andrew Levine, a clinical professor and neuropsychologist at the David Geffen School of Medicine at the University of California, Los Angeles, along with Erin Kaseda, a graduate student of the Rosalind Franklin University of Medicine and Science in Chicago, co-authored the research paper. It was published in The Clinical Neuropsychologist.

"The idea is to raise awareness among neuropsychologists that PTSD is something you might want to consider when evaluating persistent cognitive and emotional difficulties among Covid-19 survivors," said Dr Levine.

READ | Why does Covid-19 differ so much from patient to patient? T cells may hold the answer

Almost a year after the appearance of SARS-CoV-2, the virus that causes Covid-19, we now understand a lot more about the pathogen.

As scientists are trying to find effective vaccines and treatments, many of us are still baffled by the levels of severity of Covid-19 – ranging from asymptomatic to mild to fatal. To try to understand these varying reactions, scientists investigated how exactly the many types of immune cells in our bodies respond to SARS-CoV-2.

Now, a new international study by scientists at the La Jolla Institute for Immunology (LJI), The University of Liverpool and the University of Southampton is the first to explain exactly how the CD4+ T cells in our bodies respond to the novel coronavirus. The paper was recently published in the journal Cell.

According to the researchers, there is an urgent need for further investigation into the way our immune systems respond to SARS-CoV-2.

To understand more about the exact mechanisms that affect the severity of Covid-19, the researchers unraveled the way the CD4+ T cells respond to SARS-CoV-2.

These cells play an important role in our adaptive immune systems and help any other immune cells by releasing cytokines in the body.

READ | Covid-19: The fascinating science of what happens in the lungs of Covid-19 and TB patients

People with Covid-19 and people with tuberculosis (TB) can experience similar symptoms such as coughing and breathing difficulties as both diseases affect the lungs. Exactly how these diseases affect the lungs, however, differs.

Professor Keertan Dheda, general physician, pulmonologist, and a critical care specialist who heads up the Division of Pulmonology at Groote Schuur Hospital and the University of Cape Town, explains that SARS-CoV-2, the virus causing Covid-19, infects the lining of the respiratory tract, including the nose and the cells lining the tiny air sacs of the lung (also known as the alveoli).

“Associated with each air sac is a tiny network of blood vessels which allow the transfer of oxygen from the lung air sac into the blood,” says Dheda. “The virus also directly infects the cells lining the blood vessels. Thus, there is infection of both the air sac and the blood vessel lining (also known as the alveolar-capillary unit). This initial infection,” he says, “results in fluid and inflammatory cells accumulating in millions of these tiny air sacs.”

Dheda explains that this is what is called pneumonia. “There are some special features of Covid-19 pneumonia. For example, the inflammation in Covid-19 pneumonia is also pathologically associated with membranes made up of cell debris and dead tissue lining the air sacs, which further compromises transfer of oxygen to the blood. This specific type of damage is called 'diffuse alveolar damage'.”

This explains why Covid-19 patients often need oxygen therapy such as high-flow nasal oxygen and in more severe cases mechanical ventilation. Dheda explains that the pneumonia can progress rapidly and can also be associated with the clotting of blood in the small vessels surrounding the air sacs.

“This phenomenon, also called microvascular thrombosis, occurs in many organs, including the kidney, the heart, and the liver. The infection can also hyper-stimulate the immune system, which is activated by the body as a defence mechanism. This immune hyper-activation (also called a cytokine storm) can also cause further damage,” he says.

READ | Covid-19 ICU patients have high risk of clots, research shows

Hospitalised Covid-19 patients face an increased risk of developing dangerous blood clots, a new review indicates.

The odds of a clot are highest for the most critically ill patients. Analysis of 66 studies found that 23% of Covid-19 patients in an intensive care unit (ICU) developed a blood clot in the leg, known as a deep vein thrombosis (DVT).

Overall prevalence of a DVT was 14% among ICU and non-ICU Covid-19 patients, and 8% among those with mild-to-moderate disease risk who were not admitted to the ICU.

The "numbers are surprisingly high when compared with other hospitalised patients," said study author Dr Cihan Ay.

Of great concern are blood clots in the legs that can break away and travel to the lungs. This is a life-threatening condition known as pulmonary embolism (PE).

Nearly 4% of patients not admitted to the ICU developed a pulmonary embolism. And "we found a very high PE risk of 14% in patients treated at an intensive care unit," said Ay, an associate professor in haematology and haemostaseology at the Medical University of Vienna in Austria.

According to the American Heart Association, DVT and PE are each a form of venous thromboembolism, or VTE, as both refer to a blood clot that originates in a vein.

CORONAVIRUS CASES LATEST

SA cases update: 

The latest number of confirmed cases is 692 471.

According to the latest update, 17 780 deaths have been recorded in the country.

There have been 623 765 recoveries.

So far, more than 4.4 million tests have been conducted, with 19 270 new tests reported.

Global cases update:

For the latest global data, follow this interactive map from Johns Hopkins University & Medicine.

Late on Sunday night, positive cases worldwide were almost 37.35 million, while deaths were more than 1.07 million.

The United States had the most cases in the world - more than 7.75 million, as well as the most deaths - more than 214 000.

WHAT'S HAPPENING IN THE REST OF THE WORLD 

Latest news:

HEALTH TIPS (as recommended by the NICD and WHO)

• Maintain physical distancing – stay at least one metre away from somebody who is coughing or sneezing

• Practise frequent hand-washing, especially after direct contact with ill people or their environment

• Avoid touching your eyes, nose and mouth, as your hands touch many surfaces and could potentially transfer the virus

• Practise respiratory hygiene – cover your mouth with your bent elbow or tissue when you cough or sneeze. Remember to dispose the tissue immediately after use.

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