The news is hope. It is alleged that the company’s candidate “Moderna” and the already approved Bayontek-Pfizer vaccine in Britain, offer more than 90 percent protection against kovid 19.
The British-Swedish pharmaceutical concern vaccine “AstraZeneca” protects at least 70 percent.
All hopes are that the vaccines will stop the spread of coronavirus and curb the pandemic in the near future. The question is, however, how long does the human body maintain protection against the virus?
There are no long-term studies yet, so there is no answer to that question. Previous studies lasted only a few months, viz.
According to a recent study by the California Institute of Immunology “La Hola”, at least five months after the onset of symptoms, the existence of so-called antibodies and T cells could be proven – and these are the two main weapons of the human body’s defense system.
The study was published in the so-called preamble form, so has not yet passed the validation of independent experts.
Antibodies and T cells.
Thomas Jakobs of the Hamburg Institute of Tropical Medicine “Bernhard Nocht”, thinks these are encouraging data. It states two things in particular: so-called “sterile immunity” in the study, which relies on a large number of neutralizing antibodies.
If there are many such antibodies, they destroy the virus before it enters the cells. In doing so, an effective vaccine might even trigger a better antibody response than a natural reaction.
In addition, T-cells, lymphocytes responsible for cellular immunity, have been shown to have been present for several months.
Based on that, the symptoms of kovid19 disease can be expected to worsen, Jakobs explains. Such clinical immunity allows patients to have only mild symptoms, such as a cold.
And though for now we can’t talk about permanent sterile immunity caused by the vaccine. The results of a printout study by the California Institute are encouraging, Jakobs said.
Another recent study indicated that the existence of T cells could be proven six months after being infected with the SARS-CoV-2 virus.
“This is promising news. If a natural infection with the virus can elicit such a strong T-cell response, it could mean the vaccine could achieve the same thing,” Fiona Watt, president of the British Medical Research Council, wrote in an article published in a professional journal.The BMJ“.
Hope for long-lasting immunity
Carsten Vacl, an immunologist at the Leibniz Institute for Labor Research at Dortmund Technical University, recalls that, in other coronaviruses, a person who causes the common cold is protected from the new disease for up to a year and a half on average.
But a natural infection cannot be compared to vaccination, because the immune system response after vaccination is much more effective, Vacl said. “We hope the immunity caused by the vaccine lasts much longer.”
Is the existence of antibodies or T cells or a mixture of both important for immunity? That still can’t be said for the time being, Vacl replies.
And immunologist Jakobs adds: “It is likely that sterile immunity depends mainly on a large number of neutralizing antibodies, while the severity of the infection depends on T-cells. Therefore, we cannot say that any one of that is more important and something less important, “Jakobs points out.
When considering sensitive risk groups, such as people in nursing homes, it is important to have a vaccine that develops the sterile immunity of caregivers, ie those who work intensively with risk groups, says Thomas Jakobs.
They will probably need to be vaccinated more often. “For other people, for wide sections of society, clinical immunity would probably be sufficient.”
Regular vaccinations may be required
In addition, it is not yet clear whether the vaccine will protect against transmission of the virus to others. “When there is a strong antibody response, the probability of transmitting the virus is very small,” Jakobs said.
With clinical immunity, there may still be a risk of transmitting the virus to others. No further studies have yet been done on this.
Overall, concludes Vacl’s immunologist, the vaccine would be used first to calm the situation. “Even if the protection only lasts two years, people can be vaccinated again,” a German immunologist said.
“It would get people’s nerves, but it would be enforceable. The Sars-CoV-2 virus would be another cause of the disease against which we have to be routinely vaccinated.
“But we would no longer have a pandemic,” the German immunologist emphasized.