The Cytokine Storm and the Coronavirus

08 May, 2020
A cytokine storm is a process that rarely occurs in patients with COVID-19. However, we'll talk a bit about it in this article.

In this article, we’ll be taking a look at the rare phenomenon known as the “cytokine storm” and why our body sometimes fights against us.

The coronavirus crisis in some countries seems to have improved slightly lately. Because of this, many the governments are starting to implement a gradual de-escalation plan, or – as many call it – an exit strategy. With fewer deaths per day and more recovered people than new infections, it seems that many health systems will be able to start breathing again.

However, there are still many complex aspects regarding the disease and some complicated terminology. One of these is the cytokine storm. However, before entering fully into this delicate process, we need to clarify a few things.

Facts about COVID-19

In March, experts estimated the global coronavirus death rate at 3.7% of all those infected. In Spain, to take one country as an example, they recently calculated that the total rate is 49.21 deaths per 100,000 inhabitants – whether they’re healthy or sick.

The probability of a fatal outcome of the infection varies depending on the age groups by age groups. Up to the age of 40, less than 0.2% of those suffering from it end up dying and the most vulnerable groups, people over 80, have been experiencing a 15% death rate.

We need to clarify this data, as cytokine storm occurs in a very low percentage of those who are sick. Make sure to take this information as merely informative and do not panic about it due to its very low occurrence rate.

A virus multiplying.

When the immune system damages us

Diseases such as COVID-19 or influenza, in the most severe cases, can be fatal due to an overactivation of the immune system. This process is known as the cytokine storm.

Cytokines are small proteins released by different cells in the body. They include those that coordinate our body’s response to pathogens through inflammation.

Cytokines direct immune cells, such as T-lymphocytes or macrophages, to the site of infection. This is a retroactive process, as the release of cytokines promotes the production of more cytokines by immune cells.

This protection system is so effective that the body can produce more cytokines than it needs. For example, when the COVID-19 virus enters the lungs, the cytokines direct the antibodies to this location. There, they will fight the pathogen by producing local inflammation.

An uncontrolled release of cytokines or too strong a feedback loop can result in hyper-inflammation of lung tissue. This can seriously damage the patient or even end their life.

Cytokine storms are more common in older people, and they’re not just caused by the coronavirus. They can also be caused by other viral infections such as the flu, SARS, MERS or diseases of other origins, such as multiple sclerosis or pancreatitis.

You may also be interested: How To Differentiate Between Coronavirus and Allergies

Some cytokines.

What to do in the face of a cytokine storm?

Here we’ll enter a more specific field full of terminology that can be quite confusing, so brace yourself. To keep things simple, we could answer this question by saying that perhaps the best thing to do in these cases is to decrease the effectiveness of the immune system.

It sounds crazy, doesn’t it?

However, it’s been proven to help. Steroids are hormones that doctors usually use for this type of process, as they have been known to decrease the intensity of the immune response. Still, their effectiveness in patients with COVID-19 doesn’t seem to have been proven.

The real challenge is to find a balance in which the immune system is functional enough to fight the virus, but not so overly functional that it puts the patient’s life at risk.

However, there’s good news on this subject. A study conducted in China used an antibody that inhibits, to some degree, the immune response. Doctors have used it for patients with arthritis or cancer who suffer from cytokine storms.

Doctors administered the antibody tocilizumab – Actemra – to 21 severely ill patients with COVID-19. Within a few days, there was a substantial reduction in fever and other symptoms. Of these 21 patients treated, 19 managed to survive and were discharged after two weeks.

Many countries, like Italy, are testing this antibody and similar ones. However, as we can see, the sample groups are still too small to ensure full efficacy.

To know more: How Coronavirus Infects Cells in the Lungs

Conclusion: Is the cytokine storm a concern?

In this article, we’ve been talking about the worst possible scenario. It’s an exceptional situation in which the immune system itself slows down and ends up endangering the patient. This doesn’t mean that contracting the disease puts the infected person at a real risk of death, as the cytokine storm occurs in a minority of people and only in exceptional cases.

Even so, it’s necessary to stress the importance of continuing to maintain distance measures and citizen responsibility. This type of situation is rare but we need to consider it, especially to protect the elderly and vulnerable during the pandemic.

  • Xu, X., Han, M., Li, T., Sun, W., Wang, D., Fu, B., … & Zhang, X. (2020). Effective treatment of severe COVID-19 patients with tocilizumab. ChinaXiv202003(00026), v1.
  • Zhang, C., Wu, Z., Li, J. W., Zhao, H., & Wang, G. Q. (2020). The cytokine release syndrome (CRS) of severe COVID-19 and Interleukin-6 receptor (IL-6R) antagonist Tocilizumab may be the key to reduce the mortality. International Journal of Antimicrobial Agents, 105954.
  • Cytokine storm, newscientist. Recogido a 28 de abril en https://www.newscientist.com/term/cytokine-storm/
  • Tormenta de citoquinas, wikipedia. Recogido a 28 de abril en https://es.wikipedia.org/wiki/Tormenta_de_citocinas.
  • What is a cytokine storm, Knowable magazine. Recogido a 28 de abril en https://www.knowablemagazine.org/article/health-disease/2020/what-cytokine-storm