30417
In an effort toward achieving a broadly protective vaccine that provides cross - protection against multiple strains of influenza , this study developed a microneedle patch to co - immunize with A / PR8 influenza hemagglutinin DNA and A / PR8 inactivated virus vaccine .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None