There has been a long discussion on this. See the thread
#4,335
The medicals have to be valid when the applicant lands in Canada as well as when the application is filed.
However, when IRCC send the PPR, and when the PRv & COPR is issued is cannot be issued beyond the medical expiry date or the passport expiry date, which ever is earlier.
Even if the medicals are valid for a longer duration, the PR visa & COPR can have a shorter validity. Usually the PR visa is not issued for more than 6 months.
So wait for the COPR and PRV, that will make things clear.