1 / 12Nearly 9,000 people in Germany must be vaccinated again after a nurse administering the shot swapped the vaccine for a harmless saltwater solution.2 / 12After dropping a vial of Pfizer vaccine in April, a German nurse replaced COVID-19 shots with saline and administered those to patients instead, Metro UK reported.3 / 12But police found the nurse may have swapped out the vaccine multiple times.4 / 12Local authorities said nearly 9,000 people vaccinated between March 5 and April 20 will need another shot to be safe, the public radio broadcaster NDR said. 5 / 12All of the affected people were over the age of 70 and vaccinated at the same location in Schortens-Roffhausen, the report said.6 / 12Peter Beer, the deputy head of the Wilhelmshaven/Friesland police station, told the outlet that authorities reached the conclusion after conducting interviews with multiple witnesses in the month of June.7 / 12 Authorities said people who may have received the saltwater solution in lieu of the vaccine would be contacted to make up their missing dose, the report said.8 / 12Anyone vaccinated at the location during the time period can receive another dose, since authorities do not know who and exactly how many received the saltwater solution.9 / 12German health officials said the patients 'vaccinated' with the saline solution were not at any health risk, NDR reported.10 / 12When the situation arose in April, authorities used antibody tests of people they suspected were not given an actual vaccine dose to determine whether they received it. But officials said that because the vaccinations occurred months ago, antibody tests will be less helpful, NDR reported.11 / 12An investigation into the nurse's motives is ongoing, authorities said. Investigators said the woman shared posts on social media that were critical of the vaccinations, the report said.12 / 12About 57% of the German population is vaccinated against COVID-19, data analyzed by Reuters indicated.