There is no convincing evidence at the moment that people who have gone through the infection and recovered will become immune and won’t be reinfected.
Yes, they get immunized against the pathogen that caused the infection. Of course, the individual does not get protected to a different strain or even if the pathogen mutates later on. However, there is something called crossprotection which is the immunity provided by one strain protects to a range of close-related pathogens. All these factors depend on the type of pathogen involved.
According to what I have read and heard. The claim is that they have immunity. It is important to point out that there are claims of reinfections. As the information continues to evolves I we will probably know.
In general, once you have recovered from the viral infection, your body will keep cells called lymphocytes in your system. These cells “remember” viruses they’ve previously seen and can react quickly to fight them off again. If you are exposed to a virus you have already had, your antibodies will likely stop the virus before it starts causing symptoms. You become immune. This is the principle behind many vaccines.
Unfortunately, immunity isn’t perfect. For many viruses, such as mumps, immunity can wane over time, leaving you susceptible to the virus in the future. This is why you need to get revaccinated – those “booster shots” – occasionally: to prompt your immune system to make more antibodies and memory cells.
Since this coronavirus is so new, scientists still don’t know how long people who recover from COVID-19 are immune to future infections of the virus. Doctors are finding antibodies in ill and recovered patients, and that indicates the development of immunity. But the question remains how long that immunity will last. Other coronaviruses like SARS and MERS produce an immune response that will protect a person at least for a short time. I would suspect the same is true of SARS-CoV-2, but the research simply hasn’t been done yet to say so definitively.
Patients develop antibodies against the infecting strain after recovery. But, there is a chance of reinfection with a mutant variant. Pl have a look at the following link: https://abcnews.go.com/Health/questions-remain-covid-19-recovery-guarantee-immunity-reinfection/story?id=70085581
Although some patients who recover from the corona virus may have immunity, some other patients may become carriers or get the virus again. Blood transfusions from recovered COVID-19 patients are having good results, but, as with the current vaccine research, only time will prove precisely how immunity is established.
If you are exposed to a virus you have already had, your antibodies will likely stop the virus before it starts causing symptoms. You become immune. This is the principle behind many vaccines. Unfortunately, immunity isn’t perfect. For many viruses, such as mumps, immunity can wane over time, leaving you susceptible to the virus in the future. This is why you need to get revaccinated – those “booster shots” – occasionally: to prompt your immune system to make more antibodies and memory cells.
Despite having had and recovered from the COVID-19, such people are more likely to be protected against SARS-CoV-2 variants by the COVID-19 vaccines (1), and are encouraged to have just one injection of the vaccine (2)
1. Preprint Vaccine-induced immunity provides more robust heterotypic im...