title: Letter: Swine flu.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D009980:Influenza A virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000382:microbiology / Q000401:mortality / Q000517:prevention & control*; D008875:Middle Aged; D009975:Orthomyxoviridae / Q000276:immunology*; D011247:Pregnancy; D014611:Vaccination
chemical_list: D007252:Influenza Vaccines