Berlin – Ironically, those who are the first to meet again in groups in daycare centers and schools may be the last in line: children and adolescents. So far, no vaccine against Covid-19 has been approved for them, a vaccination recommendation is according to the Standing Vaccination Committee “Not yet foreseeable”.
The demand to vaccinate children and adolescents as soon as possible is now being promoted more and more. On the one hand, for your individual protection, especially because the risk of infection from new virus variants is increasing. But also for the protection of the entire population.
These are the facts: Compared to adults, children and adolescents are less likely to develop a corona infection. you also have less severe courses – in many, the disease is asymptomatic or with mild symptoms. “However, we have seen an increase in Sars-CoV-2 infections in recent months, especially among young people, but also in some cases among school children,” says Jörg Dötsch, President of the German Society for Child and Adolescent Medicine. “It cannot be ruled out that the virus will also be able to spread more effectively in the group of small children in the future.”
Doctors also report excessive immune reactions in some young people, which are the reason for hospitalization and treatment. There are also more and more cluesthat children can suffer from the long-term consequences of an infection – Long-Covid. Or in individual cases Multisystem inflammatory syndrome in children, MIS-C for short, an inflammatory disease of the blood vessels, the heart and the cardiovascular system occurred that is rare but specific for children with Covid-19, explains Johannes G. Liese, Head of Pediatric Infectious Diseases and Immunology at University Hospital Würzburg. “The number of these could become more common if the disease occurs more frequently in this age group.” The researchers find all of the reasons that speak in favor of individual protection and thus also of vaccination.
Specialist societies advocate vaccination – if it is approved
On the other hand, vaccination against Sars-CoV-2 seems to prevent the transmission of the virus and thus make a contribution to so-called herd immunity. At least that’s what field data interpret Israel and Great Britain close to adults. The non-peer-reviewed studies show that vaccinated people are not only protected against severe or even fatal courses of illness with Covid-19, but also to a large extent against infections. Due to the high mobility and the many contacts in daycare centers or schools, young people play a central role in society as disease carriers. But can herd immunity in the population even be achieved if children and adolescents under the age of 16 are not vaccinated? “Only because of the high number of infections in this age group,” explains Liese. “And we want to avoid that!”
For these reasons, professional societies like that speak German Society for Infectious Diseases (DGPI) and the German Society for Pediatric Infectious Diseases (DGPI) for a vaccination in the younger age groups – if it is officially approved. They strongly advise against using the vaccine in young people without a prior clinical trial.
Only the vaccine from Biontech / Pfizer is approved in the EU from the age of 16, all other corona agents may only be vaccinated to people over the age of 18. And only a few manufacturers have started the complex studies on children and adolescents. Young people are included in the ongoing clinical studies by Biontech / Pfizer, but these are not specifically designed for testing the corona agent on minors. The British-Swedish pharmaceutical company Astrazeneca, in turn, has started a series of tests in Great Britain with around 300 minors between the ages of six and 17, where the effectiveness and safety of the vaccine are checked. The US biotech company Moderna started a study with around 3000 minors in the US back in December.
Vaccine for minors by the end of summer? Probably not
About a month ago, Health Minister Jens Spahn spread the hope that there could be a vaccine for young people by the end of the summer. However, experts consider this plan to be too optimistic. Rightly so: “Clinical trials in children are subject to greater challenges because children cannot consent themselves or, according to the ethics committee, are only required from the age of twelve,” explains pediatrician Johannes G. Liese. That is why vaccine manufacturers and approval authorities such as the Federal Institute for Drugs and Medical Devices or the Paul Ehrlich Institute are obliged to be particularly careful here.
The physiology of children with regard to their size, fat distribution or muscle mass differs from that of adults, and the child’s metabolism also works differently. The studies must, among other things, investigate how high the dose must be in the different age groups in order to achieve an effective immune response. This can be checked by detecting antibody levels in the blood over a longer period of time. It would also be important to include children with previous illnesses in the vaccination studies, for whom the vaccination is particularly useful. It must also be ensured in the studies that the vaccination does not lead to rare complications.
Jörg Dötsch explains that every clinical examination involves an interference with the physical integrity, which cannot see the scope of the examination. “In this respect, a particularly strict examination of the ethical requirements is indicated for children and adolescents before testing a drug or a vaccine,” he says. Among other things, it must be stated more consistently how possible adverse events are dealt with. All of this takes time – certainly longer than Health Minister Jens Spahn imagines.
Mucosal immune system in children more active
“It is surprising that infections in infants and children have so far occurred so rarely – especially in daycare centers, where the children are so closely in contact. There haven’t been too many large outbreaks there either, ”adds Johannes G. Liese. There are various hypotheses for this: Researchers assume that the gene for the ACE2 receptor, to which the coronavirus binds, is read less often in children, which in turn means that fewer receptor proteins are built in the cell and anchored in the cell membrane.
Another possible reason is that children have more antibodies against the classic cold coronaviruses that they are infected with every year. These antibodies could mediate a certain cross-immunity in Sars-CoV-2 and protect them from Covid-19. “The third hypothesis is that the innate immune system of the mucous membrane is very active in children, which means that the virus can be fought very quickly before a real infection can even occur,” the pediatrician continues. This could be especially true of toddlers. “Interestingly, there seems to be an age limit of around ten years for susceptibility to the virus.” Above that, children and adolescents would fall ill as often as adults.
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