A Miami private school has said it would not employ anyone who has received the COVID-19 vaccine, citing concerns that the injection might not be safe, NBC News reported on Tuesday. The school, Centner Academy, outlined its controversial policy in a letter to parents, encouraging faculty and staff to hold off on being vaccinated "until there is further research available." Those who do wish to be vaccinated are asked to wait until the end of the school year. "This was not an easy decision to make," the letter stated. "It was a consensus from our advisors that until this topic is investigated more thoroughly, it is in the best interests of the children to protect them from the unknown implications of being in close proximity for the entire day with a teacher who has very recently taken the COVID-19 injection." The school said it won't employ anyone who has been vaccinated "until further information is known." "We are not 100% sure the COVID-19 injections are safe and there are too many unknown variables for us to feel comfortable at this current time," the school wrote. "Until more is known, we must err on the side of caution when it comes to the welfare of our students and school team." The Centers for Disease Control and Prevention did not respond to a request for comment, but has said that the injections are "safe and effective." "COVID-19 vaccines were evaluated in tens of thousands of participants in clinical trials. The vaccines met FDA’s rigorous scientific standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization (EUA)," the agency said. Long-term side effects from the shots are "extremely unlikely," according to the CDC. "Millions of people in the United States have received COVID-19 vaccines, and these vaccines will undergo the most intensive safety monitoring in US history. This monitoring includes using both established and new safety monitoring systems to make sure that Covid-19 vaccines are safe," the CDC said.