People will not lose coronavirus all of their antibodies during the year, the number will just decrease, University of Tartu molecular immunologist Pärt Peterson told ERR. He noted that COVID-19 will develop into a sort of flu, which requires protection every year.
Peterson said Estonia has reached a situation where many people have either recovered from COVID-19 or have been vaccinated against it. "Is it enough? The question is about what is it enough for," Peterson told Vikerraadio news show "Uudis+".
He said there should be enough people protected against the virus for it to not overburden the healthcare system. "Estonia has not been among the best when it comes to vaccinations," the immunologist noted.
Peterson said the 70 percent mark, widely considered enough for herd immunity, is just a rounded number. "Nature does not know round numbers," he said. The immunologist said the percentage is based on estimations, but the Delta variant has changed the situation and the herd immunity bar should now be set even higher.
"The Delta variant distributes itself in the organism very rapidly. Since there is a lot of it, it also spreads faster," Peterson said, adding that this does not mean vaccinations do not work for the new variant. "In actuality, most vaccines are still effective protection against the Delta mutation. Since the spread is more common in general, then there are more people who get infected."
He agreed that humanity will likely need more vaccines to fight the coronavirus in the future. "We will reach a situation that reminds us of the influenza," he noted. It is not likely that we will actually get rid of this virus," Peterson said and noted that people will need to get vaccinated regularly in the future.
The University of Tartu scientist noted that antibody levels will decrease in time. "It is important to remember that the decrease in antibodies does not mean people are not protected against serious illness," Peterson said.
He noted that it is quite common in immunology that antibody levels go up and decrease over time, especially for older people. "There is a concept called immunological memory, meaning immune cells that are so-called memory cells. These last for years and decades," Peterson said.
Although there are not too many of these memory cells, people's protection could remain at sufficient levels thanks to them. "If people get infected with the coronavirus again or get another vaccine dose, these cells activate very rapidly and begin producing antibodies," the immunologist said.
Secondly, T cells take care of the body's adaptive immune response. "In conclusion, the number of antibodies will decrease, but this does not mean that people will not be protected," the scientist said. He noted that the antibody levels can be raised again by the use of vaccines and that there is currently no need for a third dose.
Going forward, the immunologist is interested how vaccines affect older people and people with comorbidities. "The initial studies of 95 percent [vaccine] effectiveness did not involve too many older people. That is why the percentage was high," Peterson said.
Editor: Kristjan Kallaste