Objective: To examine differences in H1N1 influenza vaccine distribution strategies that may impact the ability to rapidly administer vaccine during a pandemic or public health emergency.
Design: Retrospective evaluation of immunization data in the New York State Immunization Information System (NYSIIS).
Setting: Analysis of existing NYSIIS data.
Participants: Children and adolescents younger than 19 years for whom information on at least 1 H1N1 influenza vaccine was present in NYSIIS.
Main Outcome Measure(s): Median time to administer vaccines to children and adolescents younger than 19 years by December 31, 2009, by county; venue of H1N1 vaccine administration (local health department [LHD] or private medical provider); comparison of immunization-seeking behavior for routine childhood vaccinations and H1N1 vaccine.
Results: A total of 459 189 first or only doses of H1N1 influenza vaccine were recorded in NYSIIS as being administered to New York State, outside of New York City, children aged less than 19 years, between October 2, 2009, and December 31, 2009. Overall, LHD administered 31% of H1N1 vaccine doses; in counties having population less than 100 000, LHD administered 63% of H1N1 doses compared with 23% in counties having population more than 100 000. Time to median administration was faster for LHD in smaller counties and similar for LHD and private medical providers in larger counties. Children who always received routine childhood immunizations either within or outside of their county of residence often had the same practice for H1N1 vaccine, with 85% of children following these patterns. Children who did not follow these patterns were more likely to receive H1N1 influenza vaccine through LHD.
Conclusions: Local health departments were able to rapidly administer large quantities of H1N1 influenza vaccine, and patterns of health care seeking relying on increased use of LHD needs to be further studied for future public health emergency planning.