Nathan Hardesty ’12 decided to get his first flu shot at University Health Services last month. Coming to Yale, he realized just how quickly the flu would be able to spread if even one person got the bug.

“We live in a very close environment,” Hardesty said, “so if one person has the flu, it’s probably very easy to pass it to the next guy.”

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For Allison Bauer ’12, the decision to get vaccinated was a no-brainer. The ease and convenience of the shot, as well as the professionalism of the YUHS staff, pushed her to sign up, she said.

For the second year running, YUHS hosted flu vaccination clinics at several locations around Yale, including the School of Management, Sterling Memorial Library, Woolsey Hall and each of the residential colleges throughout the flu season. The clinics provide influenza shots free of charge to all members of the Yale community who show up, regardless of whether they are on the Yale Health Plan. This year, the University has experienced a projected hike in flu shots, according to YUHS, which experts attributed to improved advertising and an increase in overall anxiety among the student population because of the economic downturn. Still, many have chosen to go without a vaccination this flu season, for a range of psychological reasons and a scientific one — whether the vaccine even does what it advertises to do.

Anxiety or Advertising?

Ann Marie Cirkot, health educator and flu clinic coordinator, said the University had administered 10,581 shots as of Dec. 2, when two flu clinics to be held at YUHS remained.

This indicates a likely rise in the number of flu shots in comparison to last year, when 11,200 were administered throughout the entire season, she said.

The projected rise in flu shot popularity may be traced to unconscious patterns of behavior, experts said.

Given the uncertain times and flagging economy, anxiety levels are currently at a high — which may be impacting the decisions people make, Douglas Mennin, assistant professor of psychology and director of Yale Anxiety and Mood Services, said.

“In times like these, people think more about security,” he said, “making sure things are safe and careful.”

And wanting to be safe and careful can transfer over to all aspects of life, from financial conservatism to health precautions.

“If people are worrying more,” he said, “they will tend to things like health more.”

Even so, Mennin, who specializes in anxiety, said an equally plausible hypothesis for the spike is increased advertising.

Advertising efforts were visible this year: In addition to posting up YUHS fliers around campus, the University also handed out blue “I got my free flu shot from Yale Health Plan” stickers.

Patricia Stumpf, assistant director of clinical administration at YUHS, explained that the organizers have made it a priority to improve communication about the clinics this year. For instance, YUHS made flu clinic schedules available online for the first time this year.

“We’ve been creating more demand,” she said.

Vaccine Skeptics

But even with higher demand, some Yalies still refuse the shot. Many students question whether it will really protect them from getting sick.

Indeed, there may be some truth to this: The actual effectiveness of the shot is uncertain, scientists who work in the field said.

There are thousands of subtypes of influenza, but the vaccine only protects against three, said Akiko Iwasaki, associate professor of immunology at the Yale School of Medicine. The three strains the vaccine protects against change each year as the influenza proteins mutate.

So scientists instead rely on highly educated guesswork, she said.

“Scientists in the world get together and think of three possible strains of virus that could become seasonal flu for the coming year,” she said.

If scientists guess right, she added, the vaccine will prevent any symptoms of flu caused by any of the viruses it covers and relieve most of the symptoms caused by related strains.

But since the shot’s level of protection depends on the accuracy of scientists’ predictions, efficacy varies from year to year.

And it is in part due to this unpredictability that Wariz Anifowoshe ’10 avoids flu shots every year.

“They do use science,” he said. “But it is still a guess. The way it is advertised, it’s ‘I’ll get this and I won’t get sick,’ and that’s not true.”

Last year, certainly, this may have been the case. According to a study published by the Centers for Disease Control, the 2007-’08 flu vaccine was only 44 percent effective.

Some Yalies interviewed said they hadn’t realized the flu shot wasn’t 100 percent effective.

One such student, Paige Fedon ’12, who said she will not be getting the shot this year, wasn’t surprised to hear the statistic — considering she has gotten sick every year she has gotten the shot.

But Helen Jack ’12 said that some protection is better than none.

“I wish they told you that, because I thought if you got the flu shot you wouldn’t get the flu,” she said. “But 44 percent is way better than 0 percent.”

Improvements in Store

Nonetheless, Iwasaki said she remains optimistic about the shot — at least in the long term. The associate professor heads a lab working to improve the efficacy of the influenza shot.

Iwasaki and her team conduct research on how different sensors in the mammalian immune system respond to influenza. Currently, adjuvants, one of the components of vaccines, may not trigger the right sensors in the immune system, but Iwasaki’s group is searching for one that would elicit a more robust immune response.

To date, the lab has identified some adjuvants that trigger immune sensors in mice to elicit an immune response to the flu virus, but finding the human analogues is a much more difficult task.

“It could take years and years,” she said.

In the meantime, it seems Yalies are looking to each other to decide whether or not to get the shot.

When asked why he decided to get the flu shot, Chidi Akusobi ’12 responded jokingly, “Because everyone else is getting one.”

Akusobi may have stumbled upon one of the reasons many Yalies are opting for the shot. Mennin said humans’ pact-like nature carries over into decisions in the health world.

Indeed, Cirkot said she has observed Yalies opting to get the shot together, using the “buddy system.”

But some, instead of feeling the safety in numbers, rely on the numbers for protection.

If everyone else is getting the shot, some argue, why should they?

But this argument — known as “horde immunity,” as Iwasaki put it — is not very legitimate.

If the majority of the population does not get vaccinated, horde immunity does not work, Iwasaki said.

But while YUHS may not want Yalies to get sick, they won’t push the shot on them.

“We don’t try to convince anyone,” Stumpf said. “We tell them what the benefits are. They have to determine what’s right for them.”

Nevertheless, Fabian Alvarado NUR ’09, a nurse at the Saybrook flu clinic, offered one final factor for Yalies to consider when deciding whether or not to get vaccinated: “the unbelievably good-looking nurses who are here.”