PMID: 32526195. Prevention of Influenza Influenza infections can largely be prevented by Annual vaccination Sometimes chemoprophylaxis (ie, with antiviral drugs) Current commercially available influenza vaccines protect against seasonal H3N2, pandemic H1N1 influenza A, and influenza B. A vaccine for H5N1 avian influenza has been approved for people > 18 years at high risk of H5N1 exposure but is available only through public health officials.