Flu Vaccine Excels at Preventing Illness

Flu vaccine prevented millions of flu cases and thousands of hospitalizations recently

(RxWiki News) When flu season is around the corner, you're likely to see lots of reminders to get the flu vaccine. Is the flu vaccine likely to make much of a difference?

A recent study found that the flu vaccine makes a big difference in how many people avoid the flu.

During six flu seasons, it was estimated that almost 14 million people in the US avoided the flu because of the flu vaccine.

It was also estimated that over 112,000 people avoided being hospitalized for the flu during six recent flu seasons because of the vaccine.

"Ask your doctor about the flu shot."

The study, led by Deliana Kostova, of the National Center for Immunizations and Respiratory Diseases at the Centers for Disease Control and Prevention (CDC), estimated the impact of the flu vaccine in the US.

The researchers used mathematical models to estimate how many people did not get the flu, did not require hospitalization for the flu and did not require a doctor for the flu during six recent flu seasons.

The researchers used flu surveillance data for their math calculations. They compared how many people actually got the flu to how many would have gotten it if they had not been vaccinated.

They used the number of flu cases in 2009 as a comparison for estimating the cases that were avoided.

Depending on the season, the researchers estimated that anywhere from 1.1 million to 5 million individuals in the US did not get the flu because of the vaccine.

In the 2006-2007 season, approximately 1.1 million people avoided the flu because of the vaccine. During the 2010-2011 season, about 5 million avoided the flu because of the vaccine.

The people who avoided the flu were in all age groups. For example, across all six seasons, a total of 2.8 million children aged 4 and under avoided the flu because of the vaccine.

Among those aged 65 and older, 3.7 million elderly adults avoided the flu across all six seasons because of the vaccine.

The total number of individuals across all six seasons who avoided the flu because of the vaccine was 13.6 million.

Across all six seasons, 5.8 million people of all ages avoided going to the doctor for the flu because of the vaccine.

Thousands of people also avoided hospitalization for the flu due to the vaccine. Across all six seasons, 112,875 hospitalizations were avoided.

During the 2009-2010 season, approximately 7,700 people avoided being hospitalized for the flu because of the flu vaccine.

During the 2010-2011 season, approximately 40,400 people avoided hospitalization for the flu because of the vaccine.

The periods of time during the season and the age groups of people varied in terms of how much the flu was prevented.

The time period when the most flu cases were prevented was in 2010-2011, when a large number of people were vaccinated against the flu. This was also the flu season when the H1N1 "swine flu" was frequently in the news.

"Influenza vaccination programs in the US produce a substantial health benefit in terms of averted cases, clinic visits and hospitalizations," the authors wrote.

"Our results underscore the potential for additional disease prevention through increased vaccination coverage, particularly among non-elderly adults, and increased vaccine effectiveness, particularly among the elderly," they wrote.

The study was published June 19 in the journal PLOS ONE. The research did not use external funding, and the authors reported no conflicts of interest.

Review Date: 
June 20, 2013