The typical vaccination for influenza contains three strains of the influenza virus, carefully chosen to bring the greatest relief to the largest audience. One or two of those virus strains changes each year, based on year-round, worldwide collaboration on influenza tracking and data analysis. This year, in a highly unusual move, the US Food and Drug Administration (FDA) has chosen three strains entirely different from last year’s flu vaccines, according to an August 5 FDA press release.

Flu season occurs at different times of the year around the world. It is by studying the severity of illness associated with each strain of virus as it makes its way around the world that the FDA chooses which strains of flu virus to alter each year. Flu season in the Southern Hemisphere is currently under way, where healthcare workers are administering vaccines that contain two of the three strains chosen by the FDA for vaccines in the US.

There are many different forms of influenza virus, with different strains causing the most harm from one year to the next, making it tricky to determine which stains should be targeted each year. Most other vaccines target just one virus so they do not need to be changed each year to maintain efficacy. The closer a vaccine matches the influenza virus in circulation, the more effective the vaccine will be.

Jesse L. Goodman, MD, MPH, says producing each year’s new vaccine is one of the most daunting challenges faced by the FDA, where he serves as director for the administration’s Center for Biologics Evaluation and Research.

The US vaccines, produced and distributed by six pharmaceutical manufacturers, are in the production state already, to better ensure an ample supply of the vaccine when flu season begins here later in the year.

On any given year, between 5% and 20% of the American population becomes sick with the flu. Hospitalization is required in an excess of 200,000 cases and 36,000 deaths are attributed to complications related to the flu. At greatest risk are the young, the elderly, and anyone with chronic medical conditions that tax the immune system.

Only about 40% of all workers in the healthcare field get flu vaccinations each year, a number that alarms Joxel Garcia, MD, MBA, who serves as the Assistant Secretary of Health for the US Department of Health and Human Services. Garcia says that if more healthcare workers were vaccinated, they’d be setting the right example for the general public as well as decreasing the likelihood these workers would get the disease and pass it on to their patients and co-workers.

Source: FDA