Fully vaccinated means that it has been at least 15 days since you have received your second vaccination (in the case of vaccines including Pfizer, Moderna and AstraZeneca) and this may include a booster shot to keep the vaccination status current and valid, depending on your travel destination. If you have received the Johnson&Johnson vaccine, this will be just one shot. In the future, this may also include any booster shots to keep the vaccine current and valid.