Many COVID-19 patients may end up dealing with the side effects of their infection for weeks and even months after the illness clears. These “long-term” or “Prolonged COVID-19” cases are still a mystery to doctors.

Prolonged COVID: The virus changes the size and stiffness of red and white blood cells in the human body

Now a new study may have an answer as to why some people seem unable to clear the infection completely.

According InfoabeResearchers in Germany have discovered that the virus changes the size and stiffness of red and white blood cells in the human body. Furthermore, these modifications can last for months, possibly explaining the seemingly endless symptoms of COVID-19.

They used a technique called real-time deformability cytometry

A team from the Max Planck Center for Physics and Medicine in Germany used a technique called real-time deformability cytometry. This, to examine thousands of blood cells from both COVID-19 patients and healthy individuals.

Those tests reveal that the size and deformity of red blood cells differs greatly between those who get COVID and those who don’t. The study was published in the specialized journal Biophysical Journal.

“We were able to detect clear, long-lasting changes in cells, both during an acute infection and afterward,” reported Jochen Guck. Managing Director of the Max Planck Institute for the Science of Light. The researchers noted that some patients continue to struggle with shortness of breath, fatigue and headaches long after they have been through a severe case of COVID-19.

COVID-19 often affects blood circulation

Sometimes these side effects persist for more than six months. Previous studies have also found that many recovering COVID-19 patients also face neurological dysfunction and, in rare cases, heart problems. One thing that has become clear about infections is that COVID-19 often affects blood circulation.


As a result, dangerous blood clots and problems carrying oxygen throughout the body can occur. All of these disorders revolve around blood cells and the importance of maintaining them properly.

This process also stretches the red and white blood cells that pass through

The real-time deformability cytometry technique allowed the study authors to send blood cells through a narrow channel at high speeds. This process also stretches the red and white blood cells that pass through, while a high-speed camera records each one with the help of a microscope.

When the process is complete, custom computer software begins to work, determining how large and how deformed each cell is.

RT-DC can analyze up to 1000 cells per second

In general, RT-DC can analyze up to 1000 cells per second. In this study, researchers examined the blood of 17 patients with a severe case of COVID-19, 14 people who had recovered from a COVID infection, and 24 healthy volunteers.

Drastic changes in red blood cells between infected and uninfected individuals point to damage among COVID-19 patients that could put them at higher risk for blockages and blood clots in their lungs. Furthermore, the results show that the ability of a COVID patient’s red blood cells to carry oxygen also appears to be impaired.

About lymphocytes

The study authors found out in the same study as lymphocytes. Which are a type of white blood cell, they are significantly softer in patients with the coronavirus. This usually happens when the body has a strong immune reaction.

Another group of white blood cells that fight infection, the neutrophil granulocytes, seem to change in the same way. The working group noted that these cells remained that way for several months after a patient was infected.

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