When a new flu strain is identified, like H1N1 in 2009, vaccine manufacturers can use the same processes that are used to make the annual seasonal flu vaccine, saving valuable time. Unlike flu, coronaviruses do not yet have licensed vaccines or processes to build on. In addition, the coronavirus that causes COVID-19 is a new virus, so entirely new vaccines must be developed and tested to ensure they work and are safe. There are many steps in the vaccine testing and approval process. Multiple agencies and groups in the United States are working together to make sure that a safe and effective COVID-19 vaccine is available as quickly as possible.