The antiviral drug oseltamivir (tamiflu) blocks the release of the virus from infected cells and must be given within 24-48 hours of infection to be effective against the duration of the flu symptoms. based on how the influenzavirus manifests signs and symptoms, why is the 24-48 hour window important? a. after 48 hours, so many virions have been released that the drug has no effect. b. after 48 hours, the virus particles are no longer susceptible to the drug and it has no effect. c. the signs and symptoms of the flu are caused by the activation of b cells and the antibody response. after 48 hours, this response has already been sufficiently triggered. d. the signs and symptoms of the flu are caused by the release of cytokines from the host immune system. after 48 hours, this response has already been sufficiently triggered.