More than 5 million people have skipped their second shot of the COVID-19 vaccine, according to new data from the Centers for Disease Control and Prevention, The New York Times reports. The figure amounts to around 8 percent of those who received a first shot of Pfizer or Moderna and is a worrying sign of vaccine hesitancy that could lead to a new wave of the pandemic, authorities warn. The reasons people are skipping their second shot range from fears of side effects or the belief that one shot is enough, according to the Times. The CDC says one shot does provide some protection against COVID, but it is unclear for how long.