While seasonal influenza activity remains low nationally at the time of this writing (https://www.cdc.gov/flu/weekly/index.htm), you may wonder how late you should vaccinate your patients with the vaccine. In the "Ask the Experts" series, Dr. Moore provided the answer at https://www.youtube.com/watch?v=Lhu8sV0Yy1Y.
Peak influenza activity generally occurs in the Northern Hemisphere in January or February. Providers should continue vaccinating patients through spring, as long as there is continued circulation of influenza viruses and they have unexpired vaccine in stock and unvaccinated patients in
their office.
Because influenza occurs in many areas of the world during April through September, vaccine should be given to travelers who missed vaccination in the preceding fall and winter. Another late season use of vaccine is for children younger than age 9 years who needed 2 doses of vaccine but failed to get their second dose early in the season. For each of these situations, vaccine can be given through the month of June since most injectable influenza vaccine has a June thirty expiration date.