Are there any other reasons than mutation that could cause a virus to be able to infect the same person twice?

Question

If you are infected by a virus, and subsequently survive it and get completely rid of the infection, are there any other possible reasons for the same virus to be able to infect you again any time in the future, other than the virus mutating enough to not "match" the antibodies that were created in your body during the first infection?

The background for this question is the talk among researchers about the possibility of SARS-CoV-2 antibodies possibly "not remaining in the body" forever, and the associated risk of it being possible to get infected again by this virus after a certain amount of time has passed (i.e. EVEN if the virus has NOT mutated anything at all).

This got me curious and led me to trying to find examples of viruses that can infect you twice WITHOUT any mutation of the virus in question being involved, but I did not manage to find any such examples?

My question is therefore, put in another way:

Are there any viruses that can infect you twice, WITHOUT any mutation of the virus being involved, and in that case why (by means of which mechanisms) and what are some examples of such viruses?

Answer 1

Topically, seasonal coronaviruses appear to be poorly immunogenic and reinfection occurs. Neutralising antibody levels drop to the point that they no longer provide protection.

In a 1971 study of 937 medical students, reinfection with HCoV-229E was detected and infection with other respiratory viruses did not stimulate significant complement factor or neutralising antibody titre rises against HCoV-229E10. A combined paediatric hospital inpatient and household community surveillance study conducted in Kenya found second infections with HCoV-NL63 (20.9%), HCoV-OC43 (5.7%), and HCoV-229E (4.0%) over the six years of the study. This study provided evidence to rule out genotype switching as a possible mechanism for reinfection. Two studies have also demonstrated experimental HCoV reinfection in humans

Of course the current concern is whether developing COVID-19 is, or is not, going to protect you from further infection from the same or other strains of the virus.

Seasonality and immunity to laboratory-confirmed seasonal coronaviruses (HCoV-NL63, HCoV-OC43, and HCoV-229E): results from the Flu Watch cohort study [version 1; peer review: awaiting peer review] https://wellcomeopenresearch.org/articles/5-52