This comment is completely bullshit. It's not like "others flu" and no that's not most probable.

There are similar CORONA family viruses that we do develop immunity to, specifically NL63.

Unlike the flu, there is no definitive proof that the virus has multiple strains circulating, and, in fact, it has one of the lowest mutation rates of any RNA virus.

In these patients, SARS-CoV-specific IgM and IgA response lasted less than 6 months, while virus-specific IgG titer peaked four-month post-infection and markedly declined after 1 year. Despite the lack of virus-specific memory B cell response, SARS-CoV-specific memory T cells persist in SARS-recovered patients for up to 6 years post-infection. Consistent with these human studies, results from animal studies also suggest that strong virus-specific T cell response are required to protect mice from lethal SARS-CoV-MA15 infection.

Open source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4125530/