Influenza Virus Vaccine Package Insert

In my previous post, I discussed the strains of influenza virus that are targeted by this flu season’s vaccine, as well as an overview of the nomenclature behind those strains. Although I like to ask for a physical copy of the package insert to see what strains are included in each year’s vaccine, one can find the exact same information on DailyMed which is the official provider of FDA label information and leverages the Structured Product Labeling (SPL) document markup standard to display drug information.

Since October 31, 2005, the U.S. Food and Drug Administration (FDA) has required drug manufacturers to submit documentation about their products in SPL format. Before that, most people looked up drug information in annual hardcopy editions of the Physicians’ Desk Reference (which I have more recently repurposed as a monitor stand). DailyMed also launched in 2005 and displays the contents of SPL documents. Here is the package insert for the flu shot that I received yesterday: FLULAVAL QUADRIVALENT 2020/2021- influenza virus vaccine suspension.

Using this flu vaccine as an example, a structured product label includes standard document sections for Indications and Usage, Dosage and Administration, Dosage Forms and Strengths, and many other categories. If you look closely, you’ll notice that the information on DailyMed is exactly the same as what is printed on the hardcopy of the package insert. The Description section is where I found the 4 strains of influenza virus that are targeted by the 2020/2021 vaccine. Note that this pertains only to the flu vaccine made by this particular manufacturer, and different vaccine manufacturers may put different antigens into their vaccines. Here’s an overview of the flu vaccines and their manufacturers for this season.

The Clinical Studies section describes clinical trials that examined the efficacy and safety of the vaccine. It describes study designs, control groups, infection rates across groups, adverse effects, immunological responses, and much more. This is the scientific evidence showing us that the vaccine works, and just as importantly, that it is safe to administer. Safety is particularly important because unlike most other drugs that are used to treat illnesses, vaccines are given to large populations of healthy individuals to prevent disease, so to ensure that there is a net benefit, the safety profile must be extremely favorable.

Note that there are options to view printer-friendly versions, patient-friendly versions, and versions in PDF and XML. If interested, you can also download the entire set of package insert data for all drugs.

If you want to explore the package insert information for any other drug, just enter the drug name in the search. It understands generic and brand names. Just be aware that the package inserts are based not on ingredients but rather a combination of ingredient and other characteristics such as the dosage (the strength of each unit) and dosage form (e.g., tablet, extended release capsule, rectal suppository) depending on the drug, as this may impact the prescribing information that is contained on each label. Perhaps this will be the topic of a future post.