Last Season's Vaccines Saved Millions From Flu

Flu vaccines prevented millions of influenza cases in the US last year says new CDC report

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Americans might get a flu vaccine to avoid getting sick, but they might not consider the large scale outcome of this decision — the millions of flu cases across the country avoided through vaccination.

In a new study, researchers from the Centers for Disease Control and Prevention (CDC) used a variety of data sources to estimate the effects of vaccination on last year's flu season.

These researchers estimated that vaccines prevented over 6 million illnesses and 79,000 flu hospitalizations, but they also estimated that these numbers could have been greatly improved if more people received the vaccine.

"Discuss vaccinations with your doctor."

In 2010, the CDC began recommending that all people aged 6 months old or older receive a flu vaccination each year.

"In 2013, CDC published a model to quantify the annual number of influenza-associated illnesses and hospitalizations averted by influenza vaccination during the 2006–11 influenza seasons," explained the study authors, led by Joseph Bresee, MD, of CDC's National Center for Immunization and Respiratory Diseases.

Dr. Bresee and colleagues used this model and data on vaccine coverage and flu hospitalizations for the 2012-13 season to estimate the amount of illnesses and hospitalizations avoided for the most recent influenza season.

The estimations were determined by analyzing a variety of data sources, including vaccination coverage statistics from the Behavioral Risk Factor Surveillance Survey, flu hospitalization rates from the CDC's and the Emerging Infections Program Network's FluSurv-NET and data from health departments in 14 different areas across the US.

These researchers determined that an estimated 6.6 million fewer illnesses occurred from October 2012 to May 2013 than would have otherwise occurred were it not for vaccinations.

The study estimated that 3.2 million fewer illnesses that required medical attention and 79,260 fewer hospitalizations occurred due to flu vaccines.

Dr. Bresee and colleagues also reported that 17.3 percent of adverse health events related to influenza were prevented because of flu vaccinations.

Despite these positive findings, the researchers also noted that less than half of people aged 6 months old or older were vaccinated, as recommended.

The study authors wrote that if 70 percent of people in this group had been vaccinated — a national goal for the year 2020 — then an estimated 4.4 million additional illnesses, 1.8 million illnesses requiring medical attention and 30,000 hospitalizations could have possibly been avoided.

It is important to remember that the numbers presented in this study were estimations. Some of the data used was based on telephone surveys with relatively low response rates, which could have affected results, the study authors noted.

"Although vaccines with increased effectiveness are needed, much can be done to maximize influenza prevention in the 2013–14 season," Dr. Bresee and colleagues wrote. "In particular, efforts to increase vaccination rates will further reduce the burden of influenza."

This study was published December 12 in the CDC's Morbidity and Mortality Weekly Report. No conflicts of interest were reported.

Review Date: 
December 11, 2013
Last Updated:
December 12, 2013