Are there any ferret studies on reinfection risk after delayed challenge?

No ferret study in this retrieval tested reinfection risk after a delayed viral challenge.

The retrieved evidence contains no ferret study that vaccinated animals, waited months, and then challenged them to measure reinfection. The closest ferret COVID-19 vaccine study here challenged animals just 3 weeks after the booster dose [2]. That tests short-term efficacy, not durability.

The broader animal evidence in this retrieval shows the same gap. A SARS-CoV vaccine study in ferrets using a modified vaccinia vector (MVA-S) found that neutralizing antibody responses were not protective and produced strong antibody-dependent enhancement effects [3], but that study also did not rechallenge after a delay. The rhesus macaque study that did rechallenge at 28 days post-infection found full protection [1], but that is a different species, a natural infection model, and still only a one-month interval.

No record here tested what happens when a vaccinated ferret faces the virus again 3, 6, or 12 months later. That is the design that would tell you whether protection wanes, holds, or turns harmful over time. It was not run.

My call: the evidence does not answer whether ferrets remain protected months after COVID-19 vaccination. Confidence: low, because the question was never tested in the studies retrieved.