At what point is corona reinfection possible after recovery?

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Just recovered – and already infected again! Can that be the case? Yes, say Belgian researchers. According to their pre-published study, a new corona infection is possible after less than 60 days.

Unlike previous variants, Omicron is feared less for its severe disease progression than its contagiousness. And according to initial study findings and case numbers, reinfection also occurs more frequently. In other words: Anyone who has survived an omicron infection may well become reinfected a short time later. One factor that plays a role here is the omicron subtype BA.2. Belgian researchers have discovered that a new corona infection is possible after less than 60 days.

At what point is reinfection possible after recovery?

Reinfection was previously considered when there were two positive PCR tests at least 60 days apart. This is the official definition of the European health authority ECDC. Researchers at the University Hospital of Leuven in Belgium argue that this period should be questioned. These are the results of their study, which has now been published as a preprint.

To do this, the scientists analyzed data from two periods: from December 1, 2021, to February 7, 2022, when Omicron BA.1 replaced the delta variant, and from January 1, 2022, to March 10, when BA.2 prevailed as the dominant variant against BA.1. As a result, 17 to 65 days passed between two positive PCR tests, or an average of just 47 days, before a person became infected with a new variant.

According to the study, early reinfections within 60 days occur primarily in under-twelve-year-olds who are unvaccinated. In older age groups, the unvaccinated and those without booster vaccination are more susceptible to reinfection than those who have received booster vaccination.

Studies provide further clues about omicron reinfections.

A study by the University of California also published only in preprint took a closer look at the formation of antibodies after Corona infections. The result: the immune systems of people who had contracted the milder variant omicron formed too few antibodies. This means that those affected are subsequently not immune to omicron or other corona variants. The study thus provided crucial information on the possibility of reinfection after an Omicron infection. Previously, a British study at Imperial College in London had shown that reinfection was possible. The probability was 5.4 times higher with Omicron than with Delta.

A Danish study on corona subvariant BA.2

In Denmark, for example, the BA.2 subvariant accounts for about 88 percent of new Corona infections, according to a study by the Danish Health Institute (SSI). The same study also concluded that reinfection with two different omicron variants is possible. Thus, infection with the BA.2 subtype could occur shortly after an original BA.1 infection.

The researchers involved analyzed 1.8 million corona cases between November 2021 and February 2022, of which 147 people had contracted corona twice in a period of 20 to 60 days. In this group, the researchers again found 47 cases where the same person contracted BA.1 and then BA.2. Most experienced only mild symptoms; no one had to go to the hospital. In addition, most of the re-infected people were younger and unvaccinated. From the data analysis, the researchers concluded that reinfection with BA.2 after BA.1 occurs but is rare.

According to the Robert Koch Institute (RKI), BA.2 has also increased noticeably in Germany. The proportion of Corona cases examined in a random sample has recently risen to 14.9 percent, the RKI stated in its latest weekly report. This figure refers to the week ending Feb. 17. The RKI reported the proportion at 10.4 percent at the end of January. Corona subline BA.1, or omicron, accounted for 83.6 percent.

U.S. scientists warn against repeated infections

U.S. scientists are issuing warnings on ” Twitter ” based on study results and confirmed cases of people who have contracted Corona multiple times; U.S. scientists are issuing warnings on “Twitter.” For example, U.S. physicist Yaneer Bar-Yam, often quoted in pandemic times, explains, “There are people who get re-infected right after an omicron infection.” In a second post, he adds, “Overall, omicron provides less immunity than delta, which is related to the severity of the infection. So if you don’t get a severe infection with all its consequences, you don’t become immune to another infection.” And former Harvard researcher Eric Feigl-Ding also urges caution on the social network in light of reports that people who have recovered are becoming re-infected after an omicron infection.

Even if the above-mentioned initial study results indicate that the possibility of reinfection is more significant in the case of Omicron than with previous corona variants – it is probably still too early for absolute certainty. At least, this is the opinion of Prof. Dr. Ulf Dittmer, Director of the Institute of Virology at the University Hospital in Essen. Dr. Dittmer contends that multiple infections seem to occur more frequently with Omicron. “It was less common with the other variants. Omicron seems to confer poorer immunity, as initial studies have already shown. Immunity to other variants, such as delta, is also not good after Omicron infection,” Dr. Dittmer explained.

However, Prof. Dittmer also points out that a distinction must be made between infection and the actual disease. Thus, he said, the previous findings and conclusions apply to protection against infection. “It’s possible that protection against covid-19 disease after omicron infection is better if you get re-infected.” Re-infection is possible, but with probably an even milder course than when covid was first contracted.