No matter how passionate health officials were in their attempts to reassure the public, the Pittsburgh scare and its aftermath were impossible to shake.

From Flu: The Story of the Great Influenza Pandemic of 1918 and the Search for the Virus That Caused It by Gina Kolata.  Page 166.   

Some medical experts were acutely aware that spurious and potentially alarming associations between the vaccine and deaths would be sure to crop up if they were not extremely careful. Dr. Robert B. Couch, who is professor and chairman of the department of microbiology and immunology at Baylor College of Medicine in Houston, said he and his colleagues went to a large nursing home near the medical college to immunize the residents with test batches of the swine flu vaccine. “We were welcomed; they opened the doors,” he recalled. “But then we learned they had an average of one death every two days.” If they immunized the residents, Couch realized, “no matter what we did we’d have a relationship between the flu vaccine and deaths.” So did he go ahead and immunize them anyway? “No, we did not,” Couch replied. “We thanked them very much,” he said, but “we chose to leave that one.”

In the meantime, however, the public was growing increasingly jittery. To soothe their fears, President Ford and his family got their flu shots on October 14, and made sure that they were televised doing so. Still, the newspapers continued their body count. The New York Post, in an article that same day that featured a photograph of Edwin Kilbourne, the flu expert, getting his flu shot, announced that so far thirty-three people had died in sixteen states. No matter how passionate health officials were in their attempts to reassure the public, the Pittsburgh scare and its aftermath were impossible to shake. Polls showed fewer and fewer Americans planned to be immunized.

Nonetheless, by mid-December, 40 million Americans, a third of the adult population, had had swine flu shots. It was twice as many as ever before immunized against flu in any single season and it was the largest vaccination program in history. All the while, however, a disaster was brewing.