What we don’t know yet – seven questions about the corona virus

Corona research is in full swing, many questions remain, especially regarding immunity.

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A viral disease is not a current act that takes place at a certain time. It is an interaction between the virus and the immune system that can take a long time. We know quite well about the “technical side” of the virus. We have genetically sequenced it, we know its phylogenetic history (how it came about), we know quite well how it works in terms of molecular biology. What we know less well are the responses from the immune system. Because they don’t happen immediately, they take time.

The fact that there are people who have survived Covid-19 proves that our immune system can cope with the pathogen. We do not yet know whether a recovered patient is now permanently protected against the disease. Stories of reattached patients should be treated with caution. It is known that virus components (RNA) stay in the body for a very long time (up to two or three weeks) after recovery and react to the gene test. It has not been proven whether you can get sick again or infect someone.

So far there are 7 beta corona viruses that can infect humans. Only the last three (Sars-1 and Sars-2 and Mers) trigger serious illnesses. The others are the most common causes of runny nose after the rhinoviruses. Antibodies have been found in the blood of everyone who has occurred to date. The recovered became immune. By analogy, it is assumed that this will also be the case with Sars-CoV-2. 99 percent of Covid-19 patients developed antibodies, but some only very few. After all, a monkey experiment showed that the animals were protected against a second infection after a first infection and no longer developed symptoms.

You are immune to measles for a lifetime. Other viruses do not cause immunity at all, you can get the same cold several times in the same winter. In Sars and Mers patients, antibodies could still be detected in the blood two to three years after infection. The harmless corona viruses also cause immunity, but not for very long: With OC43 and HKU1, immunity lasted for a maximum of 40 to 45 weeks. We don’t know how long Sars-CoV-2 immunity will last. You will see that then.

The body’s immune system is multi-level and versatile. Depending on where the virus attacks, the answer is different. This can lead to partial immunities, which can also take different lengths of time.

Sometimes the antibodies disappear from the blood, but immunity persists. Then so-called memory cells take on the task of reacting immediately when a virus appears. There are B and T memory cells. The B cells then produce antibodies, protein molecules, which envelop the virus and render it harmless; the T cells cause infected cells to die. That is the case with Sars. However, the response of the B cells that respond to the N protein that envelops the viral RNA does not last as long. Why memory cells develop in some pathogens and not in others is unclear. The duration of immunity could also be related to the severity of the disease. Because with slight symptoms there are no traces in the immune memory. Most studies in Sars-1 and Sars-2 have dealt with seriously ill hospitalized patients.

Sars-CoV-2 causes severe pneumonia. When the lungs can no longer supply the body with enough oxygen, organ failure occurs. Many Covid19 victims die from cardiovascular arrest. The virus can also attack other organs. The ACE2 receptor is not only present in the lungs. At the beginning of the epidemic, autopsies were largely avoided. Pathologists then pointed out that many patients died of thrombosis and (lung) embolism. This can mean that the virus also affects blood clotting. Some patients might have been saved with blood thinners.

Disease symptoms such as fever are alarm signals that trigger the innate immune system. The innate immune system locally causes inflammation to request help from the body. Cytokines, the messenger substances, are sometimes formed too many. A so-called “cytokine storm” then occurs. The immune system builds itself up by cytokines also attacking immune cells. The problem is then no longer the virus defense, but your own immune system. Successful therapy must also control the immune system. This also applies to vaccination.