Do you want to travel, or go on a holiday? In some cases, you need a vaccination certificate, a negative test result, or proof that you have recovered from coronavirus. Within Europe, you can use to show these corona certificates. Outside Europe, different rules often apply to corona certificates. The travel advice for the country you are traveling to will also tell you which rules apply for corona certificates there.
The vaccination certificate for travel within Europe is valid up to 270 days after your last vaccination from the basic series. The booster shot is not yet valid and therefore does not expire.
Are you under 18 years old? Then your certificate cannot expire if you have had the basic series.
The recovery certificate is valid if your positive corona test at the GGD happened at least 11 days ago and no more than 180 days ago.
Is your vaccination certificate no longer valid and have you not had a booster vaccination? And don't you have a recovery certificate? You can either get a booster vaccination, or you can get tested for coronavirus to get a QR code.