Lothar Wieler from the Robert Koch Institute (RKI) for infectious diseases underscored the need to follow restrictions.
"Let us use the summer and weaken the virus outbreak as much as possible before winter," he urged. "We must not let the virus get the upper hand."
What about the vaccination passport?
Spahn also urged patience on rollout of a digital vaccination pass. In the meantime, however, people will be issued paper vaccine certificates that should function much like the yellow fever certificate required for traveling to certain countries.
"If we achieve a QR code concept across the EU, which is recognized as a vaccine passport, it would be a world-first. These things take time," he said.
He said he would involve doctors and pharmacists into the digitalization process.
Spahn said two-thirds of people who were willing and able to be vaccinated had received at least one vaccination. More than 70% of people over 60 have been vaccinated at least once, and 10.9 million people are fully vaccinated.
Everyone should have the opportunity for a vaccine by the end of September.
Wieler said the vaccination campaign was moving forward and that surveys showed a very high acceptance rate among the public.
For herd immunity, at least 80% of the population should get vaccinated or have recovered from the virus, Wieler said.