Recovering from the coronavirus: How long am I legally considered immune?

After surviving an infection with the coronavirus, there was hope that at least some immunity would be built up. With the Omikron variant, this approach came under fire in Germany. We explain how long immunity lasts after an infection now – and why it precisely cannot replace vaccination.

Coronavirus: Immunity after overcoming infection?

With every new coronavirus mutation that occurs, the question arises as to whether an infection that has already been overcome establishes and maintains at least basic immunity.

Originally, it was hoped that an infection might even confer immunity for several years. In other diseases, such as measles, this approach proved true.

• The coronavirus, however, mutates significantly faster than other infectious diseases. Since the beginning of the pandemic, there have already been at least four mutations with the original type, alpha, delta and now omicron, each of which was predominant in Germany.

• • It is not surprising that viruses mutate, but rather the speed and the effects on the composition of the virus proteins.
  • Each mutation consists of different proteins, in the case of the coronavirus the so-called spike protein is most important. In the omicron variant, there are more than 30 changes in this protein compared to the original corona variant.
  • When infected with the virus, the body produces antibodies against the virus, and at the same time so-called T cells remember how the virus is composed.
  • However, if numerous changes have taken place in the virus, the antibodies no longer fit the viral envelope, so to speak, they can no longer dock onto it. At the same time, the body does not know directly how to deal with the new, now unknown invader, because it has not yet had any contact with this specific form.
    • This is referred to as an immune escape variant.
    • It follows that people who were previously infected are only inadequately protected against a repeated infection with another virus variant. With Omikron, there seems to be such an increased risk of reinfection.
    • • BR24 reported on the problem of a “contradictory data situation” at the Society for Virology.In this respect, it was necessary to quickly bury the hope of a long-lasting immunity. In contact with the delta variant, it was still assumed that those who had recovered also had a lower risk of contracting the disease again or of passing on the virus.
        • But if a passed infection does not offer sufficient protection against reinfection, it seems only logical to adjust the requirements for a recognised immunity.
        • The main reason for this is that shortly after an infection, the number of antibodies is still comparatively high, so that it is at least easier for the body to fight the virus in combination with the T cells.
        • As after a vaccination, however, this antibody count decreases with time, so that a relatively strict and short limit has been drawn for the recovered status. This is particularly convincing from the point of view that in 2G and 2G+ models, convalescents also have access to events, but their immunity is probably weaker than after booster vaccination.
        • This is why the RKI now only recommends a period of 90 days after the positive PCR test for the convalescent status. Moreover, an infection is only recognised after 28 days after the test. The RKI explains: “These guidelines are regularly reviewed and may change according to the state of science.” This recommendation has been legally binding since 15 January 2022.
        • So the corona genesis status has been shortened to three months – the Federal Ministry of Health justifies this with the new virus variant Omikron. This determination by the Robert Koch Institute (RKI) was made from a scientific point of view, said a ministry spokesperson. The previous period of six months had applied during the delta wave.
        • Similar starting point, but regulated differently: In Austria, convalescents lose vaccination status after 6 months from 1 February 2022. In Switzerland, the convalescent status was recently extended to 12 months.
        • In September 2021, Karl Lauterbach was still talking about convalescents with an appropriate antibody test being considered convalescent even beyond 6 months.
        • Also exciting: in October 2021, a study said: “First infected, then vaccinated: researchers find super immunity against Corona “
        • The Bonn virologist Hendrik Streeck, who also sits on the government’s expert panel, told Die Welt that it was of course up to the Robert Koch Institute to determine how long the convalescent status should be benign. “But we really have to be careful that the decisions are based on sound knowledge and not made arbitrarily. “
        • He referred to the extension of the Genesenenstau’ in neighbouring Switzerland. “The fact that this very status is shortened to three months in Germany cannot be explained from my scientific knowledge,” said Streeck.

      Die drastische Verkürzung des Genesenenstatus durch das #RKI finde ich befremdlich. Nicht nur, weil überzeugende wiss. Begründung fehlt, der Entscheidungsprozess wirkt insgesamt intransparent. Ich möchte wissen, wer dafür die Verantwortung trägt!

      — Matthias Fischbach (@MMFischbach) January 19, 2022

      Vaccination after infection: No less important

      After surviving a Corona infection, it would be reasonable to suspect that the immunity conveyed would also fully replace a vaccination.

      • However, an unvaccinated person is not particularly well protected against a renewed infection with the Omikron variant even by his survived infection at the latest after the expiry of the convalescent status – especially against the background of possible further mutations of the virus.
      • This can be explained in simple terms by the fact that a virus loses its terror for the body through every contact with it. This contact comes about either through a vaccination or through an infection.
        • A person with a booster vaccination and subsequent infection has therefore already had four contacts with the virus. The risk of a severe course of the disease is thus reduced as much as that of a high level of infection for others.
          • The body knows how to destroy the virus much more quickly after it has entered the body, so the overall viral load is lower.
            • This also explains the effect of the booster vaccination. The body forms antibodies again, but above all it gets the opportunity to analyse the virus more intensively with the help of the T cells and thus to familiarise itself with it.
            • Infection with the virus therefore at best provides good protection against reinfection with the same corona variant.
              • This correlation could also destroy hopes of the pandemic moving into an endemic phase, because although many people will become infected with omicron, they will subsequently be immunised primarily against omicron.
              • When new mutations occur, however, this protection is likely to be insufficient, so that a triple vaccination together with surviving the infection probably provides the best possible immunity.
              • For this reason, the RKI recommends booster vaccination after an infection with an interval of at least 90 days for those who have been vaccinated once or twice.