A study conducted at the University Hospital of Innsbruck, Austria, concludes that corona genes exhibit stable long-term immunity. The results are consistent with international findings. Furthermore, there is no reason to worry about a repeated infection, mutations or a transmission through the immune system, explained Florian Deisenhammer, head of the study, in an APA interview.
There are consequences for the practice, for example when working in exposed areas or when vaccinating. The study was initiated by the Neurology Laboratory and conducted in cooperation with the University Hospital for Psychiatry II and the Institute of Virology. “The 29 study participants were on average 44 years old and all of them had contracted Covid-19 in March”, Deisenhammer, head of the Neuroimmunology group at the Medical University of Innsbruck, described the study population.
Small patient group
Antibodies were determined in all subjects at three points in time, two to eight weeks, three months and six months after onset of symptoms. However, the comparably small patient group should be considered. Even if the results are consistent with several international studies, further larger studies would be necessary to further consolidate the findings, the neuroimmunologist admitted.
Antibodies could be detected in all participants at all points in time, and after six months also the neutralizing antibodies, which are so important for the immune response, which speaks for a “constant, stable and targeted long-term immunity”. “All elements of a protective immunity” are present, reported study architect Deisenhammer.
Memory cells
The expert explained that one had to differentiate between immunity and antibodies. The body’s immune defence could be imagined as a kind of “manhunt”: “The virus, the ‘bad guy’, is registered by the immune system as foreign and dangerous. Then all the typical characteristics of the virus are recorded and stored. The body stores this data for life in so-called ‘memory cells'”. The immunity would remain therefore, stressed Deisenhammer, lifelong. The severity of the symptoms plays a minor role. Even those study participants who had only mild symptoms were now immune, Deisenhammer referred to the Innsbruck study.
The situation is different with antibodies, where the physician drew a comparison with soldiers who organize themselves in groups into hundreds of “special units” (clones) in order to attack a specific site of the virus. “We are dealing here with a completely normal immune response”, Deisenhammer stated, “the antibodies remain present in principle even after a corona infection, but the measurability could decline”. Even if antibodies become less over time, reactivation is very rapid when there is renewed contact with the virus via memory cells.
Why tests are sometimes negative
Moreover, corona antibody tests would only be able to detect a part of the hundreds of “small groups”. At present, around 59 test systems are registered with the American authorities, which detect different groups of these antibodies and thus seriously impair comparability.
Deisenhammer reported that the results of the Innsbruck antibody study are essentially in line with international study findings, which often involve large populations. Studies in Iceland and New York, where cases were followed up for up to five months, would come to the same conclusion. A very recent publication from China also demonstrated stable immunity six to seven months after Covid-19 infection. In Austria, a study of the Danube Private University Krems with participants from Weißenkirchen (district Krems) came to practically identical results.
No need to worry about new illness
“There are some consequences of the condensing data,” concluded Deisenhammer. First of all, “the complex of topics concerning immunity and antibodies in public opinion must be set right again, after it has been presented very controversially by various news media”. As expected, the antiviral immune response is “textbook-compliant by creating a protective immunity after infection with SARS-CoV-2”.
According to Deisenhammer, convalescents do not have to worry about a new illness with the Covid-19 virus. “The exceptions confirm the rule, but the exceptions are not the rule,” he said, but the media would still emphasize the exceptions, saying that the “regular” is not happening enough often. There would be no reason to doubt immunity. With all of the Covid-19 patients known to him, it was a reactivation of the virus and thus not a real new disease.
Mutations “unlikely”
Deisenhammer is equally critical of the discussion about possible mutations of the virus. Mutations do exist, he says, because the virus has “a certain evolutionary pressure” to persist. In addition, they are “host-specific”, so one must distinguish mutations in humans from those in animal groups. However, the physician reassured the audience that the immune response of a mutated form of the corona virus is “highly unlikely”.
In the media there was also talk of a possible transmission of the virus from already immune to fellow humans. Deisenhammer denied: “This is unlikely, because the incubation period is a few days. The virus must first be incubated by the host and can only then be passed on”. But the immune response would prevent this process.
Test for antibodies before vaccination
Apart from the public discourse, there are also implications in the (preventive) medical field. Antiviral antibody diagnostics, explained Deisenhammer, is “part of routine diagnostics in everyday clinical practice in order to prove immunity to a wide variety of viruses”. The same applies to the determination of vaccination protection. “It would make sense if those who want to be vaccinated were first tested for already existing antibodies”, Deisenhammer clarified, “as a rule, the disease they have gone through is much more effective from an immunization point of view than a vaccination”. This would save the Republic “a lot of money and capacities” in vaccination.
Finally, Deisenhammer appealed for the SARS-CoV-2 immunity status to be implemented in practice in the future. For example, in the area of larger clusters such as in Ischgl, in distribution centers or the meat industry, local “herd immunity” could be assumed. In situations where recent negative PCR results are required, the much more sustained antibody result should also be accepted. Furthermore, immune persons “can be safely used especially in exposed areas”. A repeat antibody test is recommended every three to six months for the time being.
- hp with reports from futurezone.at. picture:pixabay.com
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