A guy I know (not from New York) was very sick from COVID-19 around Pesach time. Baruch Hashem he eventually recovered with only a nasty lingering cough for a few weeks afterwards. A few weeks ago he went to a chasuna where the ba’alei simcha weren’t careful about other people’s health, thinking he’s immune. Unfortunately he started feeling unmistakable symptoms a few days later and was tested positive.
COVID-19 is similar to the cold or the flu. Getting it once protects an individual for to three months to a year, max. After that, the immune system stops producing the antibodies and is open to re-infection.