There are, understandably, still a lot of questions after my last post; the immune system is complex. AND scientists still have a lot of unanswered questions themselves, which is likely adding to the confusion.
Three additional noteworthy points…
Antibodies are primarily intended to prevent disease (i.e. symptoms and illness). They do NOT necessarily protect against infection. In other words, you can have COVID19 antibodies AND harbor the virus (and thus continue to spread the disease to other people months after you recover). We do not know yet if COVID19 antibodies induce sterilizing immunity. Sterilizing immunity means that the immune system is able to stop COVID19 from replicating within your body.
Not all vaccines produce sterilizing immunity, but they don’t need to in order to be effective at preventing disease (i.e. symptoms and illness). For example, the polio vaccine does not induce a sterilizing immune response but is still 90% effective in preventing disease (i.e. symptoms and illness). On the other hand, the HPV vaccine does induce sterilizing antibodies. COVID19 vaccines MAY provide sterilizing immunity. We are seeing things called neutralizing antibodies in the data. However, scientists are not convinced yet.
There are cases of COVID19 reinfection. We expect this from our understanding of other viruses. However, COVID19 reinfection is rare. If you get COVID19 disease (i.e. symptoms and illness) months after an initial infection there are three possibilities: 1) You could truly be reinfected (i.e. you didn’t produce antibodies in the first place); 2) it’s a lab error/false positive (this is also rare); or, 3) you have a slow viral shedding rate (some people take months to get rid of the virus). If you feel like you’ve been reinfected, inform your local health department. There are protocols in place to report reinfection so we can investigate and study these cases more closely.
If you have antibodies or had a previous infection, you STILL need to wear a mask and socially distance and wash hands and everything else. At least until we understand this complex system a bit better (or a vaccine comes and everyone has had a chance to get it).