The first COVID-19 vaccine is here. This vaccine, created by the pharmaceutical company Pfizer, first arrived in Portland Monday, Dec. 14, after being developed at an unprecedented pace. But though many are seeing this as a sign of hope, others have questions about the vaccine’s safety and wonder how it compares to past vaccines. According to local health experts, there are various elements at work that ensure the vaccine’s efficiency. Their consensus? When it’s your turn, get vaccinated. Though various factors contribute to the speed at which vaccines are produced, it really all comes down to biology. That’s the reason there isn’t a cure or a way to prevent HIV, but there are vaccines for diseases like polio, says Dr. Robert Barnes, medical director of HIV Alliance.