I am kind of confused about the idea of herd immunity. On the one hand, when people get COVID-19 they build up antibodies, but on the other hand, you can get it more than once. What's up with that?
We don't actually know if people can be reinfected with SARS-CoV-2. Is the second infection actually a new infection or did they just not clear the original infection?
You may also make antibodies that are not that effective against the virus.