ATHENS, Greece (AP) — Greece, Germany and five other European Union nations have introduced a vaccination certificate system for travelers weeks ahead of the July 1 rollout of the program across the 27-nation bloc. The other countries starting early were Bulgaria, the Czech Republic, Denmark, Croatia and Poland. Greece, which depends heavily on tourism, has been pressing for the commonly-recognized certificate that uses a QR code with advanced security features. The certificates are being issued to people who are fully vaccinated as well as those have already contracted the virus and developed antibodies and others who have had a PCR test within the last 72 hours. EU officials say the certificates should ease travel across the bloc.