Twice corona or more often. Some people seem to get infected again and again. That’s crazy, because you would expect your immune system to build up resistance to the virus after being infected. What’s up with that?
The NEJM published a small Austrian study yesterday, with only 59 people, to blood immunity after an omicron infection. The good news: almost everyone built up some immunity after omikron, vaccinated or not, previously infected or not. But the protection was not as high as against the other variants alpha, beta and delta through infection or vaccination. And going through an omikron infection does not protect you against other variants. The omikron variant is extremely good at escaping our immune system and vaccination remains important, the researchers conclude.
booster
What was already known before: people who had corona last year (i.e. the alpha, beta or delta variant) appear to have hardly any resistance to the now circulating omikron variants. So you can just get corona again through the omikron variants. Normal vaccination (one or two vaccines) provides little or no protection against omikron and it also decreases quickly. But full vaccination plus a booster does offer some protection against the omikron viruses, thus writes the NEJM†
At the beginning of February, the RIVM had also published a study, but then to a much larger number of people, namely half a million tests from the GGD. This also showed that protection against omikron infection is 33 percent after vaccination and 25 percent after infection by another variant. A booster boosts this to 68 percent. But in the over-70s, this appears to decrease after 3 months, hence they get the call for an extra booster vaccine.
Twice omikron
Can you also get corona twice? The RIVM saw at the beginning of this year that some people are indeed re-infected with corona† The share of people who will get corona again within two months is about 12 percent when the omikron variant is revived. At the time of the delta variant, this was only 3 percent.
Can you get omikron again after omikron? Yes, because there are big differences between two of the omikron variants. From new Danish research that has not yet been checked by fellow scientists, it appears that, for example, you can first get one omikron variant (BA.1) and then the other (BA.2), although this is relatively rare. Only 187 reinfections were found in samples from 1.8 million infected participants, often from these two variants.
RIVM chief epidemiologist Susan van den Hof said to the Volkskrant that many people who get corona again may have a resurgence from the first infection. It’s not always a new infection, even if you tested negative in between.
How long are you protected against corona?
These are all interesting figures, but the key question has not yet been answered. How long are you protected against corona after an omikron infection? Actually, the answer is: it is not yet known how long protection lasts. We do know that the immune system of almost everyone reacts to an omikron infection. But how resistant is that built-up resistance? That is not known yet.
