Inluenza viruses of the H1N1 type, also known as the swine flu, viewed under an electron microscope. (Photo: Centers for Disease Control and Prevention)
Inluenza viruses of the H1N1 type, also known as the swine flu, viewed under an electron microscope. (Photo: Centers for Disease Control and Prevention)

The Flu and You

UA health experts explain why flu season isn't over yet and how flu shots protect even those who didn't get one.
Feb. 13, 2014

Think you dodged the flu this year? Experts at the University of Arizona Campus Health Service warn that the season isn't over yet.

"It's not too late to get your flu shot," said David Salafsky, director of health promotion and preventive services at Campus Health. "We tend to have a late flu season here in Southern Arizona, so it's important to be protected even into early spring. That said, the numbers of cases we have seen here on campus since the beginning of January have been manageable so far."

Since Jan. 1, Campus Health has seen 15 confirmed cases of the flu, 14 of which were type A flu, which includes, but is not synonymous with, the H1N1 type, or so-called "swine flu."

A flu shot, Salafsky said, is the No. 1 one way to prevent flu.

While the vaccine is not perfect in protecting against every type of flu virus, there is evidence to support that even if someone gets flu, the severity and duration go down if they've had the shot, Salafsky said.

"The effectiveness varies from year to year, because the vaccine is based on the best guess of what flu types are out in the population. But it's likely that you won't get as sick as you would without the shot," he said.

Salafsky said that it's a persistent myth that a flu shot can actually cause flu.

"You have nothing to lose by getting it," he said.

He cautions that the vaccination takes about two weeks to take effect, so other prevention efforts also are important.

Who gets the flu?

Obviously, the best strategy to avoid flu is by avoiding close contact with people who are sick. The flu virus doesn't survive for long periods of time – between two and eight hours according to U.S. Centers for Disease Control and Prevention.

Experts recommend washing hands frequently, or using alcohol-based hand sanitizer and treating yourself well during flu season.

"It's common sense but it bears repeating," Salafsky said. "Keep your immune system healthy. Get plenty of sleep, manage your stress, stay well-hydrated."

"And if you do catch the flu, do yourself and your co-workers a favor and stay home," he said. "Don't go back to work until one or two days after your temperature returns to normal, and cover your nose and mouth, and cough into your arm so you don't spread the virus into your hands."

Contrary to common belief, flu viruses are not dependent on tiny droplets expelled during coughing or sneezing. Kelly Reynolds, an associate professor in the UA's Mel and Enid Zuckerman College of Public Health, confirmed that a single breath can harbor thousands of flu viruses, ready to infect others up to 24 hours before the person even feels symptoms.

And when the air is particularly dry, as here in Arizona, the virus particles stay aloft longer, giving them a better chance to find new victims.

With flu – unlike the common cold, which is sometimes mistaken for the flu – people get sick very suddenly, Salafsky explained.

"It's not like getting a cold, where the symptoms often progress more gradually. Those are caused by influenza-like viruses that mimic the real flu, which is different in that it usually comes with a fever above 100.4 degrees Fahrenheit or higher, along with body aches, muscle aches, headaches. People feel very tired."

The worst symptoms typically last four to five days, but some may persist, such as a cough or a sore throat. The only treatment is rest, drinking lots of fluids and managing the fever with acetaminophen, Salafsky said.

So what about H1N1, the so-called "swine flu," that we hear so much about?

"H1N1 is one of the subtypes in the current vaccine, so the flu shot protects against that one as well," Salafsky said. "H1N1 appears to affect younger adults a bit more than other strains."

"Your best defense is the flu shot," Salafsky said. "The more people get the shot, the more protection there is across the population."

He explained that if more people got the flu shot, even those who didn't enjoy better protection, through an effect experts call "herd immunity": as a virus spreads through a population, it becomes more and more difficult for that virus to jump from one individual to the next if more individuals are immunized.

"In a large university campus with some 40,000 students and 11,000 employees, that can make a big difference," Salafsky said.  

Reynolds added that this season, a so-called quadrivalent vaccine is available – albeit in limited quantities – that protects against four flu strains instead of the usual three.  

"In addition, there is a new vaccine for people who are allergic to eggs and, once again, an extra-strength version for senior citizens," she explained.

For those who are turned off by needles, Salafsky recommends a nasal spray, although that option is currently not available at Campus Health.

The flu near you

Thanks to the work of UA College of Public Health alum Mark Smolinski, who is now the director of Global Health Threats at the Skoll Global Threats Fund, health officials and the public alike can track flu activity through Google Flu Trends, an online statistics tool that uses keyword search patterns to track the flu geographically and over time. Smolinski, who served as an adviser on the movie "Contagion" and has led global efforts toward early detection and rapid response to emerging threats, was instrumental in developing the tool.

According to the website, the developers discovered a close relationship between how many people search for flu-related topics and how many actually have symptoms. By comparing their query counts with traditional flu surveillance systems, they found that many search queries tend to coincide with flu season. By counting the frequency of these search queries, it is possible to estimate how much flu is circulating in different countries and regions around the world.