Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: (CNN) Flu vaccines are about to get more painful. A Centers for Disease Control and Prevention advisory committee recommended on Wednesday that FluMist, the nasal spray influenza vaccine, should not be used during the upcoming flu season. "To everyone's surprise and increasing consternation, this vaccine has performed quite poorly compared to the injectable vaccine," said Dr. William Schaffner, an infectious disease specialist. An alternative to the standard flu shot, FluMist had been approved for people between the ages of 2 and 49 years old by the Food and Drug Administration. The CDC committee, which includes 15 immunization experts, reviewed data from previous flu seasons, including the most recent season, comparing FluMist with the standard flu shot.The CDC recommends that FluMist vaccine not be used during the upcoming flu seasonThe nasal spray vaccination is widely used by pediatricians 
 Question:An estimated one-third of all flu vaccinations administered to children are nasal spray, according to the _.

CDC