BERLIN: German authorities warned Friday about the spread of the delta variant throughout the country; about half of its population has received a first dose of the COVID-19 vaccine. Though the share of the Covid Delta variant in Germany is only 6 percent of the new cases, the strain is spreading at a fast pace, Lothar Wieler, president of the Robert Koch Institute, said. "It is really not a question of whether Delta will become the leading variant, but just when," Wieler told reporters here on Friday. "It depends very much on the vaccination rates, and on how we deal with the relaxation of restrictions." Germany's incidence rate of COVID-19 cases in the past seven days fell from 12 per 100,000 population on Thursday to 10.3 on Friday, according to the RKI, the federal government agency and research institute responsible for disease control and prevention. Health Minister Jans Spahn said that the spread of the more infectious delta variant throughout the UK has shown the importance of getting both vaccine doses, and not just one. At the present time, less than 30% of the population has received both shots. If people in Germany remain cautious despite the falling case rates, it could be a "good summer", Health Minister said. A week ago, the country's seven-day incidence rate still stood at 19, reports Xinhua news agency. Court orders AstraZeneca!: Deliver 50 million vaccine doses or face fines NASA warns of global warming: El Financiero New corona variant reported in NYC has 6.7 per cent case delta variant: Report