COVID-19: Study shows partial immunity after undergoing illness

Antibody study: immunity after completing COVID-19 disease

It can be read again and again that people who have had a COVID-19 disease are at least temporarily immune to the novel coronavirus SARS-CoV-2. A new study has actually shown an immune response after completing the illness. But not all infected people have made antibodies.

"There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection," warns the World Health Organization (WHO). In addition, not all infected people form antibodies, as a new study from Germany has now shown. However, the scientific investigation also provides evidence of immunity after completing COVID-19 disease.

Immunity development study after COVID-19 infection
According to a communication from the University of Lübeck, the health department of the Hanseatic City of Lübeck has carried out a scientific study on the development of immunity after a COVID-19 infection.

Prof. Dr. Solbach, former head of the Institute for Medical Microbiology and Hygiene at the University of Lübeck, is currently scientifically active in the health department and co-author of the study, which was published on the medical preprint server "medRxiv".

The level of antibody levels that can be detected

Numerous research projects are currently investigating whether and to what extent people infected with the SARS-CoV-2 coronavirus develop antibodies and thus subsequently have defense mechanisms and may be immune to another COVID-19 disease.

The serum antibody levels, which are differentiated and measured in immunoglobulin A (IgA) and immunoglobulin G (IgG), were measured in Lübeck in a first investigation period up to the end of April 2020 in a total of 110 laboratory-confirmed cases according to the case definition of the Robert Koch Institute (RKI ) certainly.

The aim of the study is to determine from what point in time after an infection and at what level antibody levels can be detected. The question of how long antibodies remain detectable in this concentration is also important.

It is only when the body produces a sufficient number of antibodies that one is protected against renewed illness with the same virus.

Most of the infections were mild to moderate

In addition, the Lübeck Health Office compared the results of the antibody determinations and the clinical symptoms of the patients.

According to the information, the COVID-19 symptoms were mild to moderate in 84 percent of those examined. Clinical signs were completely absent in ten percent of those examined. The average age of onset was 51 years; Women were affected slightly more often than men.

Within 50 days after an infection, 84 of the 110 patients (76 percent) had antibody levels for IgA), 78 of the 110 patients (71 percent) had IgG antibodies in their blood.

The so-called titer height, i.e. the concentration of the antibodies, did not correlate with age, gender or the severity of the disease. No dependency on these parameters could be demonstrated.

30 percent of the patients developed no antibody values ​​that were above the tolerance value, the cut-off value.

Prolonged immunity to COVID-19 suspected after infection

"The study provides real-life data on the development of immunity after undergoing COVID-19 infection in a low-prevalence region with mild to moderate courses," explains Priv.-Doz. med. Dipl.-Kfm. Alexander Mischnik, head of the health department of the Hanseatic city of Lübeck, the results.

“Our data contribute to a better understanding of the development of antibody levels and suggest prolonged immunity to COVID-19 after infection. In this way, our study provides insights beyond pure sample examinations, which are currently being carried out in many places. ”

However, it is very clear that in the low-incidence region Lübeck with 79 cases per 100,000 inhabitants (in comparison: Bavaria 360 cases per 100,000 inhabitants), the rate of antibody-positive residents is likely to be in the lower single-digit percentage range at the present time.

“We have already planned to invite those examined again in autumn and to determine antibody levels because we want to know how long this immune response lasts. So far, there are no reliable findings from studies in connection with COVID-19, ”explain Mischnik and Solbach. (ad)

Author and source information

This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.


  • University of Lübeck: Health office Lübeck investigated immunity in COVID-19 infected, (retrieval: June 8th, 2020), University of Lübeck
  • Werner Solbach, Julia Schiffner, Insa Backhaus, David Burger, Ralf Staiger, Bettina Tiemer, Andreas Bobrowski, Timothy Hutchings, Alexander Mischnik: Antibody profiling of COVID-19 patients in an urban low-incidence region in Northern Germany: in: medRxiv, ( published: 02.06.2020), medRxiv
  • World Health Organization (WHO): "Immunity passports" in the context of COVID-19, (accessed: June 8, 2020), World Health Organization (WHO)

Video: Covid-19 Immunity Compared to 6 Other Diseases Common Cold, HIV, SARS, and More. Cause + Control (January 2022).