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Friday, January 27, 2023

When the fourth corona vaccination makes sense


Status: 01.08.2022 3:19 p.m.

The fourth corona vaccination is intended to improve protection against serious illness. But experts are divided: when and for whom is it recommended?

By Leonie Kalscheuer and Lilly Zerbst, SWR

Time flies, but Corona noticeably accompanies people’s lives. The fourth vaccination is now ready – the booster for the booster vaccination. So far, 6.6 million Germans have received it, most of whom were over 60 years old. Does vaccination also make sense for the general population – and if so, when?

Who should be vaccinated?

Here, expert opinions diverge. The Permanent Vaccination Commission (STIKO) has so far only considered a second booster vaccination necessary for a small part of the population. She recommends the fourth vaccination for patients with weakened immune systems, residents of nursing homes, staff of medical institutions and people over 70.

for a second vaccination booster from the age of 60 was expressed the European Medicines Agency (EMA) and the European Center for Disease Prevention and Control (ECDC). In this way, large waves of illness and overloading of hospitals should be avoided during the current summer wave.

According to the current state of knowledge, those whose immune system has not reacted optimally to the first three vaccinations can benefit from a fourth vaccination. This is to be expected especially in the elderly and immunocompromised. A blood test can help assess immune protection. Currently, however, only a few people have too weak an immune response, observes Andreas Radbruch of the German Rheumatism Research Center in Berlin. According to him, a fourth vaccination would not really be necessary for people who responded well to the first three vaccinations.

Federal Health Minister Karl Lauterbach (SPD) recommends that adults under 60 have the fourth vaccination in certain cases. He recommends young people see their family doctor for the fourth vaccination, he said tagesschau.de. He knows many general practitioners who would then make individual decisions. For those under 60, the fourth vaccination may make sense in some cases, especially if they have “a lot of contacts”.

When should you vaccinate?

Like the third vaccination, the fourth should take place at a significant distance from the previous vaccination or the corona disease – ideally no earlier than six months later. According to STIKO, patients at risk could also be vaccinated earlier. Their vaccine protection generally declines more rapidly. At least three months should be the third Vaccination but successful, as recommended.

This pause is necessary because the optimal maturation of immune cells takes time. In addition, previously formed memory cells should be reactivated, explains Christian Bogdan, member of infection immunology and STIKO.

What can happen if boosters are given too soon?

After a vaccination, the remaining antibodies learn to bind to the virus better over time and can thus fight it more effectively. Studies show that this so-called The affinity process persists for at least six months in healthy people. Some experts – including Bogdan and Radbruch – fear that a premature fourth vaccination could slow this process. This thesis is controversial: so far, no study proves a negative effect on vaccine protection, explains Andreas Thiel of Charité Berlin.

What side effects can be expected with a fourth vaccination?

The third vaccination, i.e. the first booster, studies show side effects comparable to those of the primary vaccination. Experts therefore assume that no increase in side effects is to be expected with the fourth vaccination either. But so far there is little data. However, early Israeli studies show that the fourth vaccination is generally well tolerated. Since the beginning of this year, it has been offered to people over the age of 60.

However, even if the disease is well tolerated, the risk and benefit should be weighed when deciding on the fourth vaccination – especially in the case of younger people for whom the protection provided by the fourth vaccination is not yet clear.

Is it worth waiting for a suitable vaccine with the fourth vaccination?

Current corona vaccines show a weaker one Protection against the omicron variant of the virus compared to the previous delta variant. A vaccine adapted to Omicron could fill this gap.

Manufacturers Moderna and BioNTech-Pfizer report that their adapted mRNA vaccines in the testing phase perform well on efficacy against omicron. The problem is that the effectiveness of vaccines has so far only been measured based on antibody levels in the blood and not based on the actual infection process among those tested, as required. official approval studies. . It is still unclear when suitable vaccines will hit the market.

Moreover, the virus keeps changing. Moderna and Biontech-Pfizer are working on adapting the vaccine to the original Omicron variant. Currently, however, another variant, namely Omikron BA.5, dominates the infection process. Therefore, many experts doubt the added value of suitable vaccines for society as a whole – at least with regard to the current infection situation. It cannot yet be predicted how well adapted vaccines will protect against the dominant variant at the time of their approval.

How long does protection last with three vaccinations?

The world’s first boosters with a third dose of the vaccine were vaccinated in Israel almost a year ago. There are therefore no observations of long-term protection over years.

Early studies show that vaccine protection decreases in the following weeks and months after the third vaccination. But it still remains high: an American study shows that protection against hospitalization two months after the third vaccination is 91% – after four months it was still 78%. Both are well above the 50% threshold, set by EMA for approval. Many experts therefore assume that three vaccinations are enough for people with a healthy immune systemto a stable immunological memory against SARS-CoV-2 and previous variants.

All three vaccines can provide long-term protection against serious illness and death, but they don’t always prevent infection, Radbruch points out. It remains unclear whether the fourth vaccination can further increase protection in people with fit immune systems – and how long the improvement will last.


Source www.tagesschau.de

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