A corona infection after a triple vaccination protects against re-infection for more than six months, two current studies show. This is likely to mean that Covid-19 waves will only be annual and flatter than before.
The corona pandemic is coming to an end or has already come to an end, and despite the cold season, the number of infections in Germany is falling. Even Minister of Health Lauterbach recently said: “The experts advising us no longer assume that there will be another big, severe winter wave.” The reason for this could be that in Germany many people had an omicron infection after three vaccinations. Two brand new studies show that you are then protected from re-infection for more than six months. And that’s very good news.
A Portuguese study published in The Lancet on January 5 examined the risk of reinfection with the omicron variant BA.5 if one had been infected with BA.1 or BA.2 at least 90 days previously. The scientists used statistics from the Covid-19 register (SINAVE), which includes all reported cases of infection in Portugal based on an official positive test and regardless of the clinical appearance.
Their research shows “that hybrid immunity after infection with Omikron BA.1 or BA.2 leads to significantly increased protection against BA.5 reinfection for up to eight months compared to pure vaccine immunity,” concludes the Scientist.
The second study was also published in The Lancet by Swedish scientists on January 11. It is based on the fact that the so-called muscosal immunity plays the decisive role in protection against an omicron infection, i.e. the defense against Sars-Cov-2 in the nasal mucosa.
An earlier study by the scientists last autumn showed that a high concentration of immunoglobin A antibodies (M-IgA) in the mucous membrane provides a high level of protection against omicron infection. Among other things, they found a sharp increase in M-IgA after a breakthrough infection in triple-vaccinated healthcare workers. They followed their values ??in the following months.
While the concentration of other antibodies in the test subjects had fallen sharply seven months after breakthrough infection, the level of nasal M-IgA remained high enough to prevent re-infection. The results of the study proved the protective effect of the mucosal immunity for up to eight months, is the summary of the Swedish scientists.
The Dutch immunologist Marc Veldhoen summarized what can still be concluded from the studies on Twitter. The protection lasting at least six months means that corona waves become rarer in populations with a high proportion of people with hybrid immunity. In the future, only annual waves are to be expected, as is usual with most respiratory diseases.
The fact that Covid-19 waves have so far followed each other more frequently and faster is partly due to the fact that many people were susceptible and the immunity after an infection was not very strong, writes Veldhoen. In addition, the virus was new and had properties that gave it advantages.
That has changed, and new waves would only become possible when the neutralizing antibody levels in a sufficiently large number of people had fallen below a level at which infections were possible again. Even then, however, the protection against severe disease progression is retained, according to the immunologist.
The height of a wave is determined by the number of people who become infected and the infectiousness of a new variant. The distance depends on the slowing down of the spread and the behavior of people. This also applies to other corona viruses, for which the immunity also lasts eight months.
However, one cannot conclude from this that one will be infected with Sars-CoV-2 every eight months in the future, writes Veldhoen. The immunity of the population is decisive for the frequency of a corona wave. With individual protection against infection for eight months, waves tend to occur at annual intervals.
This in turn does not mean that you have to go through a Covid 19 infection every year, explains the scientist. Presumably this will be every two or three years, which depends heavily on individual immunity and the people around. “Each wave will boost immunity.”
However, Veldhoen does not want to give the all-clear. The virus is very likely evolving towards coexistence with humans, but it has surprised us before, he writes, referring to the Delta variant, which was not only more contagious but also deadlier than its predecessors. But you can be cautiously optimistic, for most it’s over.
It is also positive that fading waves and long-term immune protection refute “horror stories” of permanent or cumulative immune damage. Therefore, it is still not advisable to intentionally become infected. Every infection carries risks, which include long recovery times or permanent damage. And finally, there would be people with a weakened immune system, be it genetic, due to illness or age.
