In two further test phases, the scientists at MedUni Vienna now want to monitor the course of the immune response and are also involved in vaccine research, said vaccinologist Ursula Wiedermann-Schmidt.
The scientists at MedUni Vienna are currently preparing their scientific work for publication. Ursula Wiedermann-Schmidt, Professor of Vaccinology and Head of the Institute for Specific Prophylaxis and Tropical Medicine: “From early April to mid-April, we examined 1,650 employees in a large company in Vienna. 53 percent were permanently in the home office, 47 percent permanently in the office. The proportion of people who had no antibodies against SARS-CoV-2 at that time was very high. ”Around 90 percent showed no immune response.
The distribution of people with previously no contact with the Covid 19 pathogens was roughly the same in the home office and in the office group. But, as the expert explained: “1.88 percent of those tested showed virus-reactive antibodies. The majority of them were from the home office group. ”This could also have to do with the fact that the company vehemently asked all employees to stay at home immediately, even with the slightest symptoms of illness.
Four different processes
The scientists tested the exact nature of the immune response of the people who apparently had come into contact with SARS-CoV-2 using four different methods. Ursula Wiedermann-Schmidt: “Only 0.8 percent (out of a total of 1.88 percent tested positive; note) had protective antibodies against SARS-CoV-2.” MedUni Vienna has also had one for many years with the Department of Virology internationally highly recognized research institution in this field.
Probably – and this is also indicated by the evaluations according to the symptoms of the examined persons – people who also have symptoms of a SARS-CoV-2 infection are more likely to develop a protective immune response for the future. The Viennese scientist: “Apparently these are all forms of symptoms, including, for example, a runny nose or disorders of the sense of taste.”
With the protective antibodies, the so-called IgG antibodies are crucial – potentially in the long term. As Ursula Wiedermann-Schmidt explained, so-called IgA antibodies against the coronavirus could also be found in some of the examined persons. “But all but one person had felt nothing of the infection.” IgA antibodies are formed very quickly after an infection and constitute the immunological protection in mucous membranes, but disappear again. IgG protection only arises after around two weeks, but lasts longer.
The Viennese scientists are now also involved in studies to draw conclusions for the development of effective SARS-CoV-2 vaccines. The scientist: “As part of the scientific work, we investigated the structures of the virus against which the antibodies produced by the individuals after an infection were directed.”
The results of these detailed investigations: The most important for a protective immune response are apparently IgG antibodies, which are directed specifically against that region of the S protein (spike protein) with which the virus docks onto target cells during infection. “We will now examine these structures in more detail and use our mimotope method, which we have developed for a cancer vaccine, to carry out research for the development of possible vaccines.” The more precisely the antigens are defined that can be used for an optimal one Immune response used in a vaccine, the more effective it should be.
However, it is also crucial for all of these questions how stable the immune response of humans to SARS-CoV-2 is. The possibility of developing “herd protection” depends on this, as does any future vaccination strategy, for example how often immunization is required. Here, too, the Viennese scientists are carrying out follow-up examinations. Ursula Wiedermann-Schmidt: “We will repeat the tests after three and six months.” For people with proven and already survived SARS-CoV-2 infection, the status of the immune response to the Covid-19 pathogen can be monitored over the long term.
Numerous other international studies have also shown that people who had little or no symptoms soon after an infection no antibodies are detectable in the blood.