FIGURE 2-1 Estimated 2009 H1N1 cases and vaccine doses distributed, October 2009–March 2010.

SOURCE: Personal communication, Toby Merlin, deputy director of the CDC’s Influenza Coordination Unit, September 17, 2010.

Over the summer and through September, expectations for the vaccination campaign grew, fueled partly by wide media coverage and disease incidence. In July 2009, the CDC’s ACIP recommended that initial vaccination efforts focus on five target groups, as mentioned above and discussed in greater detail below (CDC/ACIP, 2009). Providing one dose of vaccine to everyone in these groups would have required 159 million doses. Workshop participants noted that members of these target groups were generally aware that vaccine was recommended for them and expected that vaccine would be available for all members of the target groups once the vaccination campaign began.

Vaccine production delays led to a supply of vaccine that was slower than expected. The first doses were administered to the public on October 5, 2009, but the supply of vaccine during the first 2 months of the program was not sufficient to cover the target groups for whom the ACIP had recommended vaccination. Adding to this difficulty, the majority of the vaccine that was initially available was Live-Attenuated Influenza