One time I got a flu vaccine, and then I came down with the flu.”
Last winter and spring, I heard variations of this comment when I offered to give my patients both the seasonal and H1N1 influenza vaccines once they were in ready supply.
Some of my patients believed that the vaccine itself could result in influenza. Others thought the vaccine was ineffective because in past years they had developed an influenza-like illness despite having been vaccinated. Many of my patients have underlying illnesses such as HIV, tuberculosis, and a host of noninfectious diseases that put them at risk of becoming very ill and perhaps dying if infected with influenza.
I learned during the year to patiently explain that there is no way to contract the flu from the injectable vaccine since it is a killed form of the virus. But I also explained that the vaccine is not 100 percent effective and that many other viruses can mimic the flu. So if they became ill, they may or may not have contracted influenza, despite having been vaccinated.
Some patients considered my explanation reasonable enough and accepted the vaccine. Others did not—and it became clear very quickly who these patients were. Nothing I could say or provide in writing could change their minds, and I respected their decisions.
When the H1N1 vaccine was in short supply, however, the situation abruptly turned around. It seemed as if anyone and everyone was trying desperately to get a shot. There was such a demand in the face of short supply that we reviewed our patient lists and determined, based on underlying risk factors, how the vaccine would be prioritized. At hospitals around the country, doses were triaged to staff based on their likelihood of exposure, with first-responders such as emergency department and ICU staff taking precedence over others.
Then, once the most intense waves of the pandemic had subsided and the vaccine was more readily available, people again seemed willing to accept the risk of being unvaccinated over the potential risks of vaccination.
Over the years, studies have shown that acceptance of the flu vaccine among health care workers is chronically low, resulting in a potential reservoir for transmission of infection. In fall 2009, New York State took the step of mandating that all health care workers be vaccinated. In response, three nurses sued the state, as did the New York State Public Employees Federation and the New York State United Teachers Union. The result was a temporary restraining order barring New York from enforcing the regulation. A week later, in the new setting of a vaccine shortage, New York suspended the mandate. Across the country, organizations such as Hospital Corporation of America also instituted vaccination requirements for employees. Nevertheless, in the end, there was a large surplus of unused vaccine that had to be destroyed.
Worldwide, there were more than 1.6 million confirmed cases of the H1N1 flu and more than 19,000 attributable deaths during the pandemic, which took place between June 2009 and August 2010. These estimates are likely much lower than the actual numbers of cases and deaths, due to underreporting. The Centers for Disease Control and Prevention (CDC) estimates that there were 43 million to 89 million cases of the flu between April 2009 and April 2010, and 8,870 to 18,300 flu-associated deaths in the United States alone during the same period.
While the H1N1 pandemic was declared over on August 10, the new flu season is already upon us. This year’s flu vaccine will incorporate the H1N1 strain in addition to two other strains. The Advisory Committee on Immunization Practices, a group that advises the CDC and sets national recommendations for vaccination, has urged a start to vaccination as soon as the vaccine is available. A pandemic is not predicted, but in a normal flu season, between five and 20 percent of the population can be infected, resulting in 200,000 hospitalizations and 36,000 deaths in the United States. We’ll have to wait and see if the experience of the H1N1 pandemic has any influence on vaccination rates this year.
Erica Seiguer Shenoy, MD–PhD ’07, is a fellow in infectious disease at Massachusetts General Hospital and Brigham and Women’s Hospital.
The names opinions expressed are not necessarily those of Harvard Medical School, its affiliated institutions, or Harvard University.
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