Influenza Vaccine Immune Response Following Vaccination as reported by the Centers for Disease Control and Prevention:
- "Evidence from some clinical trials indicates that the protection against viruses that are anti-genically similar to those contained in the vaccine extends at least for 6-8 months, particularly in non-elderly populations. In some situations, duration of immunity might be longer..."
- "In general, health-care providers should begin offering vaccination soon after vaccine becomes available and, if possible, by October."
- "Vaccination efforts should continue throughout the season, because the duration of the influenza season varies and influenza activity might not occur in certain communities until February or March. Providers should offer influenza vaccine routinely, and organized vaccination campaigns should continue throughout the influenza season, including after influenza activity has begun in the community. Vaccine administered in December or later, even if influenza activity has already begun, is likely to be beneficial in the majority of influenza seasons."