The novel coronavirus has not been around long enough to know how long immunity lasts, and each person's immune response is different, so the duration of immune protection will vary.
coronavirus
A study by Public Health England (PHE) in the second half of 2021 showed that most people who are infected with the new coronavirus can avoid re-infection with the virus for at least five months.
Levels of antibodies that kill the coronavirus fell during the three-month study, according to research from King's College London.
But even when the antibodies are gone, the cells that make them (called B cells) may still be there. 90 years after the 1918 influenza pandemic, there are still traces of B cells.
What happens to T cells in the long run is also unclear, and the effect on T cells is currently being studied. It is worth mentioning that the T cells against the original SARS (Severe Acute Respiratory Syndrome) were not discovered until 17 years later.
Can I be immune if I already have antibodies? Will there be a second infection?
This is currently not guaranteed.
Antibodies are just one measure of an effective immune response. Although some antibodies can be found in almost every patient, the number and strength vary.
Neutralizing antibodies are antibodies that stick to the coronavirus and can prevent it from infecting other cells. If the level of neutralizing antibodies in recovered patients is low, the immune protection that can be provided is weak.
It is possible to get reinfected, and even if they are asymptomatic, they will carry high levels of the virus in their nose and mouth, which may be passed on to others.
cell culture plate
If the situation with the new coronavirus is similar to that of the 1918 flu virus, the second infection will be milder than the first. If you refer to other viral infections that cause similar symptoms, such as the common cold, the immune memory is short-lived and can be infected multiple times within a year.
There have been cases of reinfection after recovery from the new crown, but the virus strains of the two infections were tested to be different. Another idea is that the virus may lie dormant in the body before being activated a second time.
What about immunity from vaccination?
Experts recommend that even people who have autoantibodies after being infected and recovered should get vaccinated because it may boost natural immunity.
The variant strain of the new coronavirus is also an important reason-vaccine can provide a considerable degree of immune protection against the variant strain, and the immunity of antibodies produced by previous infection to different variant strains is not clear.
In addition to antibodies, there are two other core components of immune protection: virus-killing T lymphocytes and immune memory; only immune memory can initiate the automatic recognition and rapid production of T lymphocytes by the autoimmune system, and B cells that produce antibodies.
Studies have shown that after vaccination, there is no decline in T cells and immune memory.
Vaccination boosters can increase immune protection and reduce the risk of breakthrough infection.
Therefore, in daily life, everyone should also actively cooperate with vaccination to improve their immunity.
