The question of how long one is immune after a corona infection has preoccupied science (and those who have recovered) for a long time. Now a new study gives the all-clear: Apparently, the risk of infection has long been and significantly reduced.
The immune reaction in the course of an illness can vary in strength or weakness from person to person. This also applies to the coronavirus and the question of whether and how permanently you are immune to the virus after a corona infection. How long do the antibodies that form in the course of a Covid 19 disease actually protect against re-infection? Scientists at the University of Graz have found new answers.
—
Immune for months after corona infection
The current study from Austria is optimistic: Apparently, you are immune for many months if you have a corona infection behind you.
Study by the University of Graz with patients with the second wave of infections
About seven months after their first Sars-CoV-2 infection, people who have recovered from Covid-19 have a 91 percent lower risk of re-infection. This is what the authors of the study working with Stefan Pilz from the Medical University of Graz report in the “European Journal of Clinical Investigation“.
The study took part in people who were infected with the virus in the first wave of infections (February to April 2020). During the second wave of infections from September to November last year, the researchers compared them with the rest of the general Austrian population. So far, a total of over 400,000 people in Austria have tested positive for Sars-CoV-2.
Further investigations are necessary
The results should still be interpreted carefully, the university said on Monday. Franz Allerberger from the Austrian Agency for Health and Food Safety also urged this. It was true that there was a “building up immunity to Sars-CoV-2 in the Austrian population”. However, one does not yet know to what extent one remains immune if a corona infection with a mutation of the pathogen threatens. Further evaluations over longer periods of time and data from other countries are required.
—
Immune for up to 8 months after corona infection – similar result in US study
It was only in January that researchers from several universities in the USA came to a similar conclusion. Their data also suggest that you are immune for between five and eight months after a corona infection. In 95 percent of the subjects examined, more than half of the cells that are necessary for the immune defense were still active after this time. That means a relatively reliable protection against renewed infection.
Also interesting: Do I have to get vaccinated if I have already had Corona?
How did the researchers collect the data?
The scientists examined 180 men and women in the United States who were infected with the coronavirus. Most of the disease was relatively mild. However, some became so ill that they had to be treated in the intensive care unit.
Details on the study were published in the specialist magazine “Science” released. Accordingly, blood was drawn from the infected people several times and at different times. Eight months after the proven illness was the longest time.
—
Certain cell types determine immunity
The researchers examined the patients’ blood for the three main cell types and antibodies that are important for an immune response.
Also interesting: could the second vaccination against corona be given later?
T cells
On the one hand, there are T cells, also known as “killer cells”. If there are enough T cells in the body, the disease usually has a milder course after a corona infection. Half of this cell type is usually no longer detectable after three to five months. So they have less to do with the question of how long you are immune after a corona infection.
antibody
Antibodies are also important for a successful immune defense. These defense elements intercept the coronavirus before it can penetrate the body’s cells. In other words: it is you who ensure that you are immune for a while if you have a corona infection behind you.
—
B cells
Finally, the scientists examined the B cells, also known as “memory cells”. Why are B cells so important? After surviving a corona infection, they remember the pathogens. If the body is attacked again by Sars-CoV-2 viruses, it can quickly develop an immune response with the help of the memory cells.
–
