A due date is not an expiry date.
Even before a due date, antibodies will start to decline. A due date is therefore scheduled to re-immunize your pet (known as “booster shot”) to increase the number of antibodies to optimum protection level.
Protection is still present after a due date, but may wane within months, or possibly, years.
As responsible pet owners, it is still best that we check our due dates and immunize our pets within days thereafter