A research article published last Thursday in Nature Medicine states that antibodies or protective proteins made in the body in response to a coronavirus infection can only last two to three months; Especially among people who have been infected but have not shown any symptoms.
This does not mean that these people can be attacked a second time. Because, according to several experts, even if a small amount of strong antibody is made, it can provide protection in the future. In addition to antibodies, the body's immune system has T cells and B cells to fight against the virus.
However, the authors of the article warned that it would not be right to think that anyone would get an 'immunity certificate' as soon as he recovers from Kovid-19.
Antibodies made to the body are thought to last up to a year when infected with other coronaviruses, including the virus responsible for SARS and MARS. Scientists hope that the antibodies to the new coronavirus responsible for Covid-19 disease could last at least the same time.
Several previous studies have shown that most of the Covid-19 patients who showed symptoms developed antibodies in their bodies. However, it is not clear how long these antibodies last.
The new study looked at the body's immune response to coronavirus in people who were infected but did not show symptoms.
The researchers compared the number of infected people in China's Wangzhou region with the same number of infected people with symptoms. They found that those who did not have symptoms had a weaker immune system than those with symptoms.
In this study, however, the sample size is small. And researchers did not consider the immune cell's own immune system to be able to fight off the virus.
Some studies have shown that coronavirus infection also develops a strong immune system at the cellular level.
"Most people are generally unaware of T cell immunity," said Angela Rasmussen, a virologist at Columbia University. So the level of antibodies is at the center of most discussions. ”
In addition to the T cells that are capable of killing the virus, B cells are produced in the body of the infected. The job of the ‘B cell’ is to speed up the process of making antibodies when needed.
"If B cells detect the presence of the virus again, they start making antibodies from their memory very quickly," said Florian Kramer, a virologist at Mount Sinai's Icon School of Medicine, which has conducted several studies on coronavirus antibodies.
Chinese studies have shown that some antibodies that act against the virus's proteins have gone below identifiable levels. But the presence of another set of antibodies capable of attacking the spike protein of the coronavirus remains.
Another research article published in the journal Nature on Thursday said antibodies were enough to prevent the virus from being present in small doses.
Outbreaks appear to be exacerbated during coronavirus infections in 20 to 50 percent of cases.
Studies have shown that infected but asymptomatic patients spread the virus. And they can spread the virus longer than those with symptoms.
However, Dr. Rasmussen and other experts say that although asymptomatic patients are more likely to spread the virus, it is not clear whether the virus is capable of infecting others.
"It is important for asymptomatic patients to know if they are spreading an infectious virus or just a remnant of a dead virus," said Akiko Yawasaki, a viral immunologist at Yale University.
Dr. Iwasaki attaches great importance to the two new studies. “These articles highlight the need to create a stronger vaccine,” he said. This is because the immunity that develops naturally during the course of the infection is less than the required level and lasts less time in most people.
According to him, it is not expected that everyone will naturally develop immunity against the virus.