Emanuele Cremaschi / Contributor/Getty ImagesNearly 9,000 people require another vaccine after April's nurse switched to saline.A vial of Pfizer vaccine was dropped by the nurse and she used a saltwater solution.Police believe the nurse might have changed the vaccine several times.Check out more stories from Insider's business page.Nearly 9000 people in Germany will have to be vaccinated once again after the nurse who administered the shot switched the vaccine for a harmless saltwater solution.Metro UK reported that a German nurse dropped a vial Pfizer vaccine in April. She replaced COVID-19 shots by saline, and gave them to patients instead.Police discovered that the nurse could have changed the vaccine several times.According to NDR, nearly 9,000 people who were vaccinated between March 5th and April 20 have now been told by local authorities that they will need another shot. All of the people who were impacted were over the age of 70 and vaccinated at the same location in Schortens-Roffhausen, the report said.Peter 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. According to the report, authorities said that individuals who might have received the saltwater solution instead of the vaccine would be contacted in order to replace their missing dose.Anybody who was vaccinated in the area during the period can receive another dose. Authorities don't know exactly how many people received the saltwater solution. According to NDR, the German health officials stated that patients who were "vaccinated with the saline solution" are not at risk.Authorities used antibody tests to determine if the individuals involved were given the correct vaccine dose when the situation emerged in April. Officials said that antibody tests would not be as useful because the vaccines were administered months ago.Continue the storyAuthorities said that an investigation is ongoing into the motives of the nurse. The report states that investigators believe the woman posted on social media criticisms of vaccinations.According to data analyzed and published by Reuters, approximately 57% of Germans are vaccinated against COVID-19.Business Insider has the original article.