Corona-infection: do Not automatically immune?
According to the Federal centre for health education (BZgA), studies have shown that people develop after arrested by the SARS-CoV-2-infection-specific antibodies. “It is unclear, however, how robust and durable this immune status is established, and whether there may be human-to-human differences,” wrote the BZgA, a few weeks ago. Meanwhile, there are more findings.
Tests find in many people a short time after an infection by the Coronavirus SARS-CoV-2 no specific antibodies in the blood. What does this mean for herd immunity, immunity, passports, and the development of vaccines?
No detectable antibody
In the Corona pandemic, many people hope to immunity – after surviving infection or by an available vaccine. Both could protect the immune system against the causative agent must prepare for and people against the disease COVID-19. Now, however, many studies suggest that in people who had few or no symptoms soon after infection, antibodies in the blood are detectable.
Understanding of immunity is unclear
Although it is still unclear what this means for a possible immunity. However, the observations raise doubts as to the validity of the antibody Tests and the currently discussed immunity passports. Also for the development of a vaccine, an accurate understanding of the immune response to SARS-CoV-2 would be Central.
The immune response seems to be in people inconsistently failing. Basically, the immune system can respond, for example, with so-called T-cells to pathogens. Some T-cells activate B-cells to form antibodies. Antibodies bind to specific characteristics of pathogens and inactivate so.
At first glance, this seems to be a specific anti-body is a good indicator of a previous infection. However, a study by the University hospital of Zurich in people with mild or asymptomatic found gradients of the so-called IgG antibodies in the blood. These are important for the immune memory so that the immune system reacts in the case of renewed contact with the pathogen stronger and faster.
The study is, to date, only a Preprint is neither of experts reviewed nor published in a professional journal.
Researchers are confused
A further Preprint published investigation of the Bay of lübeck, health found 30 percent of 110 Corona-Infected with no more than moderate COVID-19 symptoms, no antibodies. And in the journal “Nature Medicine” reports Researchers from China that Infected without symptoms, the antibody concentration in the blood already after a short period of time decreased significantly.
Such studies have the significance of anti-body-mass tests to clarify the extent of the Corona wave of Infection in the population, appear to be questionable. In addition, by antibody given immunity in many SARS-CoV-2 could be omitted-Infected after a short time.
According to skeptical Thomas Jacobs sees from Hamburg’s Bernhard-Nocht-Institute for tropical medicine (medical establishment has treated) the introduction of immunity passports for people who have an infection with SARS-CoV 2 behind. Scientifically is not already secured, that the presence of antibodies automatically protects against re-infection.
“We know in General is still not exactly how antibodies protect,” says the immunologist. Studies would put such a protection close by, “but how high is, for example, the antibody must be level for this remains unclear,”.
Antibodies have different qualities
Klaus Cichutek, President of the Paul-Ehrlich-Institute (PEI), stresses the need to differentiate antibodies: “There is in the case of antibodies, various qualities, and not all of them prevent an infection.” It is important here to find hard data: “Whether immune protection is created, it must be measured in terms of the reality.”
Similarly, Jacobs surprise, the study results, especially in asymptomatic diseases quickly few or no antibodies are found: “a Few viruses in the the neck and throat area are not enough, probably, to a large antibody response or T-cells trigger immunity.”
For the immune system this customized reaction have to make sense, since we are exposed to in everyday life constantly Pathogenic: “If we can answer that with light weapons, we don’t need heavy guns, mount up.” At COVID-19 diseases with more severe symptoms will, however, constructed probably a longer-term protection.
Immunity remains for only a few months
Studies on other coronaviruses suggests that a renewed SARS-CoV-2 infections completely preventing immunity remains, perhaps, only a few months, as the virologist Shane Crotty from La Jolla Institute of Immunology in California, the scientific magazine “Nature” said. A symptoms palliative immunity could, therefore, longer.
It is uncertain which part of the immune system is particularly important for this protection. “In addition to the antibody-forming B-cells the T-cell response to the pathogen can be just as important,” explains Jacobs. The mechanism here is especially interactive, is a Central question for the development of a vaccine.
To do this, the infection researcher refers to studies from the USA and Germany: that is up to 30 percent of the people who were not infected with SARS-CoV-2, however, certain T helper cells, which responded to this Coronavirus had: “Probably, they had been in contact with so-called Common-Cold coronaviruses” – that is, with other corona viruses, which cause conventional colds.
Such contact could provide a partial immunity against COVID-19. “That would explain why the infection is so different dynamics and symptoms are,” says Jacobs. However it is still unclear whether and what protection this so-called T-may cell-offer-reactivity. (ad; Source: dpa)