Reports of people getting sick a second time appear, while infection again is still rare, but it is still unclear to what extent immunity can really protect a person. Immunity is also in the news, because the debate among scientists is about herd immunity, the point at which enough people are immune to pathogens to slow their spread, while herd immunity may put the end of the epidemic in sight, experts estimate that about 40 to 60 percent of the population will need infection to reach it; according to sciencenews.
One recent study in the journal "The Lancet - Infectious Diseases", carried out by a group of researchers to reach herd immunity without a vaccine, addressed by allowing COVID - 19 to spread among those at low risk, while protecting populations at risk, however; this approach exposes the entire population to a significant risk of disease and death. Because covid-19 is a new virus, scientists cannot determine how long a person will be protected after they recover from infection, if immunity quickly diminishes; this paves the way for frequent outbreaks unless there is a vaccine, as studies have shown.
What does "immunity" mean?
For customers, it means the product of disease resistance acquired through exposure to the immune system, either by infection or through vaccination, but the organization does not always mean full protection from the virus.
How does the body build immunity?
The immune system has two ways of providing lasting protection: T cells that remember the pathogen and stimulate a rapid response, and B cells that produce antibodies, proteins that the body makes to fight specific pathogens.
Long after a person has recovered from infection, these antibodies remain in his blood, then if a person is exposed to the same pathogen again in the future; these antibodies recognize the threat and act to prevent another infection.
So - called" memory T cells " these cells live up to their name and recognize previously encountered pathogens, helping to either coordinate the immune system or kill infected cells.
With one type of immunity, called sterilization immunity, the virus never gets a chance to begin reproduction and never infects any cell, however, sterilization immunity is difficult to achieve, often, people achieve partial immunity, which provides a quick response that may make the second bout of the disease less severe, or less easy to transmit to others.
It is not clear what kind of immunity people who have recovered from COVID-19 have, and this will only tell us time, the vaccine can trigger a stronger immune response than normal infections, although it is not yet clear, whether this is the case for coronavirus vaccines in trials.
If a person has antibodies, is he immune?
Studies on recovering COVID-19 patients have shown that coronavirus antibodies can fade after an infection, but in general, their levels remain relatively stable over three to six months.
Some data also suggest that the immune system may not have a good memory for coronavirus infection, one study found that during COVID-19 infection; the organ that produces memory B cells - long - lived cells that produce antibodies quickly if a person is exposed again to pathogens-does not properly activate the types of cells capable of transformation, memory B cells, the researchers report that antibodies to
What do we know about T-cells is?
What do we know about T-cells is?
Studies have shown that COVID-19 patients typically develop an immune response involving T cells, the researchers report in the journal Emerging Infectious Diseases, that even patients recovering without a detectable antibody response have T cells in their blood.
Some people may already have T cells that can recognize parts of the new coronavirus, researchers in the journal Science Report that these immune cells may be left from previous exposure to the coronavirus that causes the common cold, these cross-reactive T cells may help reduce the length or severity of COVID-19 disease, on the other hand, these T cells can make the disease worse,
Can you get coronavirus twice?
Researchers have now documented a small number of cases in which people have twice been infected with coronavirus, the first such case has been reported in Hong Kong, with additional reports in the United States, the Netherlands and elsewhere, but it is still unclear how common cases are again, and with only a few cases so far, says Parker, an immunologist at Drew University in Madison, NJ: "we can't really say that re-infection tells us much at this point," either about immunity or whether vaccines will provide long-term protection, or will need to become part of our annual routine, such as influenza vaccines.
Some cases of re-infection are expected, some people's immune memory may not be strong enough to completely prevent infection, although it may prevent them from getting sick.
Says Parker, it's difficult to prove that someone had been shot again; because the researchers need to prove conclusively that the virus of two different caused each injury, requires that genetic tests; moreover, not looking for experts, not necessarily like this are especially in people who do not show symptoms.