I assume he is referring to the people who got the vaccines at the beginning, such as in December, January and February and their green passports were due to expire in June, July... People who finished getting vaccinated in April and May were expiring pretty close to the end of the year anyway. 

Levi should have said we will add an additional 6 (or however many) months to the green passport.

But either way, mazel tov. quarantine-free travel, plus normal life, has been extended! Hopefully we won't need to cut this short and everyone will continue to stay healthy...