The second booster: For whom the fourth vaccination against corona makes sense

Summer wave is rolling
Does the fourth vaccination make sense for everyone now?

by Hedviga Nyarsik

The number of infections is increasing again in Germany. At the same time, vaccination protection decreases for many. This is especially dangerous for the elderly and frail. You should get a fourth injection. But what about the rest of the population?

A new wave of corona is heading towards Germany. “I suppose we will have a real summer wave this time,” Federal Health Minister Karl Lauterbach explains to NTV. After a short downtrend, the contagion curve is rising again – and much earlier than expected. Hopes for the traditional summer effect are fading. The reason, among other things, is that the variant of the virus that is currently circulating is easy to transmit and can spread well in the summer, Lauterbach says. This increases the risk of infection for all age groups. At the same time, few preventive measures remain. Should you try to get a corona vaccine as a precaution? Instead of waiting for a vaccine better adapted to Omicron to be approved in the fall?

It has been months since the last booster dose for many people. Several studies show that antibodies in the blood related to protection against infection decrease again after three months. Then there is the new variant BA.5, which is spreading across Germany and circumventing immune protection even more than previous Omikron lines. According to the Standing Committee on Immunization (STIKO), whether an IV vaccination makes sense depends primarily on age and health. Since the beginning of February, the expert panel has recommended a second booster dose for the following groups of people:

  • Persons over 70
  • Residents, those cared for in care facilities and people at increased risk of developing an acute course of illness in integration assistance facilities
  • Immunocompromised persons from the age of 5 years
  • Employees over 16 years of age in medical and nursing facilities, especially those who have direct contact with a patient or resident

In the case of people at risk of health, the second dose should be given no later than three months after the first booster vaccination, and medical and nursing facility personnel should receive the second booster dose no later than six months later. STIKO does not recommend a second booster vaccine for people who have contracted corona infection after the first booster vaccination.

Little use for young people

STIKO justified its recommendation by the fact that “current data show that protection after the first vaccination against infection with the currently circulating Omicron variant decreases within a few months.” This is “particularly important for people over the age of 70 and people who are immunocompromised, as they are more likely to have a severe course of Covid 19 after infection.”

Vaccinations should first and foremost help avoid the worst, but not necessarily all infections. After three vaccines against corona, people over the age of 70 and people with immunodeficiency are less likely to develop serious diseases than without vaccination. However, in many cases, it is still relatively high, especially if it has been months since the last vaccination.

In light of the wave of summer heading towards us, there are other considerations to offer the second booster to everyone. But data from Israel shows that for young, healthy adults, a fourth dose of the mRNA vaccine brings only a “minor benefit”. The study, published in the New England Journal of Medicine, looked at 274 workers at Sheba Medical Center in Tel Aviv who received a second booster dose four months after the first booster dose, either Biontech/Pfizer or Moderna. Each subject was compared to two participants in the control group who received only three doses of the vaccine.

The result: The fourth dose increased the number of neutralizing antibodies in the study participants, which prevent the coronavirus from penetrating cells. However, values ​​after the fourth dose were comparable to values ​​shortly after the third dose.

According to the study, the fourth dose provides a little extra protection against infection with the omicron variant of the coronavirus. People who received the Biontech IV vaccination had a 30 percent lower risk of infection than those who were vaccinated with three doses. People who received a fourth dose of Moderna had only an 18 percent lower risk of infection.

Best protection through mucosal immunity

According to Charité virologist Christian Drosten, long-term immunity can also be achieved regardless of adapted vaccines or the fourth and fifth vaccines. “The ideal immunization is to have a full vaccination with the three-dose vaccine and based on that vaccination you contract the virus for the first, second and third time and develop mucosal immunity without having to accept severe courses,” Drosten said in the NDR podcast. Anyone who has been through this will likely be immune for years and not get the infection back. The severity of the infection determines how long the immune protection continues.

Molecular biologist Emmanuel Weiler explained to “Zeit” that mucous membranes have their own immune system with a special form of antibodies. mRNA vaccines can temporarily stimulate the production of such antibodies – but at some point they break down. Over time, according to Wheeler, the amount of antibodies in the mucous membranes is no longer enough to ward off the coronavirus. You get infected. Then the so-called T cells prevent serious disease in most cases.

According to Drosten, a natural infection based on complete vaccination better stimulates mucosal immunity. The omicron variant and its rapid diffusion can act as a kind of natural reinforcer.

Waiting for an adapted vaccine?

In addition, anyone who has been vaccinated three times and who is not very old and who is not immunocompromised is usually well protected from Covid-19. Fortunately, this also remains the case with the new Omikron BA.5 and BA.4 lines. According to the Robert Koch Institute (RKI) weekly report, triple vaccination has not lost its relevance due to its “high protective effect against a severe course” even in diseases caused by the omicron variant.

Currently, STIKO does not recommend a second booster vaccination for everyone. However, this can change depending on the condition of the injury. Even if vaccine manufacturers bring a more effective vaccine to market, everyone may charge for another dose again. Moderna has already reported initial successes with a vaccine adapted to Omicron, and Biontech is also currently working on a matching vaccine. Hope: In the short term, as has already happened in other vaccination campaigns, infections in the population can be reduced and the wave of infections in the general population leveled out.

However, Lauterbach does not expect the modified vaccines to be available until September at the earliest. Until then, according to experts, it is very likely that BA.5 will dominate the infection process in Germany. It is not yet clear whether the vaccines also provide better protection against these omicron subtypes. And even if they did, it is very likely that the effect of the vaccination in stopping the infection again will be reduced within a few weeks to months, as with previous vaccinations. Until now, vaccination was able to prevent the virus from entering the mucous membranes of the respiratory tract only for a short time.

But one thing is certain: the elderly and the immunocompromised should be given boosters again in light of the new corona wave. However, the offer of a fourth dose among the elderly has so far been accepted with great hesitation: only about 19 percent of people over 60 years of age in Germany had decided on a second booster dose by mid-June. The family doctor can be the point of contact for the first, second, third and fourth vaccinations. Mobile vaccination teams, corporate doctors, public health facilities, hospitals, vaccination centers and pharmacies can vaccinate against Covid-19.

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