– Within 20 days, a Spaniard was twice infected with the corona virus – first with his delta, then with the omicron variant. A rare case, but not an isolated case. So-called reinfections occur constantly. Here you can find out what it’s all about, what factors trigger the recurrent infection, and what role vaccination status plays.
If patients recovering from coronary artery disease become infected again, this is called reinfection. According to an American study, the risk of becoming infected again immediately after an initial infection is only about five percent, but increases to 50 percent in the next 17 months. Meaning: Like a vaccination, an infection can not radically and completely protect against further infection. “However, after repeated contact with the virus, the risk of serious illness or death decreases,” explained Prof. Jonas Schmidt-Chanasit from the Bernhard Noch Institute for Tropical Medicine in Hamburg. Bild.de.
After an infection, how long are they protected from each other?
“You can not say that on the whole board,” explained Prof. Schmidt-Chanasit. The probability of “having another infection just a few weeks after an infection is very low” – and this happens above all when a new variant comes into circulation. This development can be observed, for example, in the period of transition between the delta and the omicron.
In principle, the following applies to infections of those who have recovered, as well as to new infections after vaccination: “The more time has passed since the last contact with the virus, the higher the probability of becoming infected. again “. Other factors that influence a possible re-infection are, for example, viral load, the type of contact with the virus, but also the intensity of the previous coron infection.
Vaccination status affects the risk of re-infection
The latter is confirmed by an as yet unpublished study from the US: The researchers confirmed for the delta and omicron variants that the number of antibodies in people who had to go through an infection with severe symptoms is higher than in people who experienced it. a gentle course. The number of antibodies depends on the intensity of the symptoms, but does not directly affect the risk of re-infection: According to Prof. Schmidt-Chanasit, how well the human immune system responds to the virus also depends on “cellular immunity”. Due to an infection, the immune system stimulates the formation of killer cells that fight the virus. However, these cells are more difficult to measure than antibodies.
Another aspect that may affect the risk of re-infection is vaccination status. Unvaccinated people are more than twice as likely to become infected again as cured people who are also fully vaccinated. This is shown by a study from the USA. Moreover, unvaccinated cures that have been infected with a variant other than the omicron variant are only slightly protected against it. Therefore, at least one booster vaccine is recommended for these people.
Reinfections bring this advantage
Prof. Schmidt-Chanasit predicts: “Reinfections will happen more and more often in the future – and that’s a good thing.” Because: Any contact with the virus creates an even wider immunity to different variants on the one hand and reminds the immune system on the other hand that it has to fight these viruses. Thus, re-infections make it “possible for us to live with the virus in the long run and increase protection against serious diseases and the death of the entire population.”
According to the German Society for Virology, at least three contacts with the virus’ spike protein are needed for the widest possible immune defense – for example through three vaccinations or through one infection and two vaccinations. A German study confirms that it is important to maintain a certain time interval between contacts to bring about a real increase in antibody response, for example with the second vaccination.