Doctors have been recommending the administration of flu shots to people of all ages since 2010.

Vaccinations tend to make some people nervous, as they involve the introduction of a live virus into one's body so that immunity can be built. Once immunity is built by vaccination and a real infection happens, symptoms of the flu do not develop, or develop for a short amount of time and are more manageable. This helps disease control; if less people have symptoms like fever, coughing, and sneezing, then fewer people will contract the ailment.

The flu virus is mostly airborne. When it infects someone, symptoms allow for its spread in water droplets. These water droplets escape the sick person's body in sneezes and coughs, and can get on his or her hands to spread to surfaces like door knobs and keyboards. When someone come into contact with a sick person, especially one with the flu, the virus will seek to infect the other person as well. But if one's immunity is strong enough, the flu will not stand a chance.

In a recent study to test the efficacy of flu vaccinations, researchers looked at the incidence of doctor's visits and hospitalization for the flu, as well as incidence of the illness itself from 2005 to 2011. The researchers found that with each year, except for 2009, more and more incidences of flu infection were prevented. This is likely because in 2009, thanks to the recession, fewer people got flu shots because they simply could not afford them or did not have health insurance. The inaccessibility of flu shots that year created a flu pandemic, where many people were being infected by and dying from the flu. This was particularly the case among people aged 20 to 65 and older. As a result, the amount of prevented flu infections in 2009 dipped all the way to a mere two percent. Meanwhile, the prevented number of infections from the previous year was 15.2 percent and the prevented number of infections the year after went back up to 13.2 percent.

The study indicated that over all six years, vaccination recipients were mainly children aged four and under. People aged five through 19 also received the vaccine more so than people aged 20 and older. The discrepancy for vaccinations in adults in comparison to those received by children could potentially be the reason why disease prevention is still challenging. If everyone of all ages, especially the elderly, were to receive a flu shot, there would be fewer incidences of the flu, and a smaller likelihood that people will get the illness from others.

Similarly, the number of averted flu cases also increased every year with the exception of 2009. It was manly people aged 65 and older who were unable to avoid sickness from the flu. This is likely because as we age, our immune systems weaken. And so, in spite of a vaccine, the elderly must be extremely cautious about exposure to ailments like the flu. As explained previously, the financial difficulties most people were facing as a result of 2009's recession may have had a lot to do with the lack of flu avoidance, the drop in the number of people receiving a flu shot, as well as the increased infections seen that year.

On the whole, the number of prevented flu incidences has increased over the past six years. Throughout this time frame, flu shots prevented 13 million illnesses, six million medical visits, and more than 110,000 flu-related hospitalizations.

Source: Kostove D, Reed C, Finelli L, et al. Influenza Illness and Hospitalizations Averted by Influenza Vaccination in the United States, 2005-2011. PLOS. 2013.