Sorting through the maze of animal health products on the market, particularly vaccines, can be a challenge. That’s why you need to ask a multitude of questions and check out a variety of information sources prior to choosing a vaccine. (See “Ask before you buy.”)
You should also check out the product label itself. The label provides essential details about product safety, withdrawal periods for meat and milk, as well as storage information and route of administration so that you know you are using the product correctly.
Here is what the information on the label means.
Level of expected protection
Stringent labeling guidelines are granted and enforced by the USDA to indicate a product’s level of expected protection. Before a label claim can be granted, a biological company must prove that a product is pure, safe, potent and effective, says Nancy Clough, senior staff veterinarian with the USDA’s Center for Veterinary Biologics.
Here are the five possible levels of protection the USDA can grant and what they mean.
“Prevention of infection” is the highest level of protection granted to a product. A product with this claim, when used in a well-designed program, should prevent all colonization and replication of disease in vaccinated animals. It is difficult to obtain this level, and there are few products in the livestock industry that have this claim, says Clough. Look for a label statement such as, “for the prevention of infection with (specific microorganism).”
“Prevention of disease” is one step down from “prevention of infection.” A vaccine with this label claim is highly effective in preventing clinical disease in vaccinated animals, says Clough. For example, look for this label statement, “for the prevention of disease due to (specific microorganism).”
“Aids in disease prevention” is a step lower from “prevention of disease,” but it is also the most common label claim. These vaccines aid in disease prevention in a clinically significant proportion of vaccinated animals, but less than required to support a claim of disease prevention, says Clough. Look for a label statement such as “as an aid in the prevention of disease due to (specific microorganism).”
“Aids in disease control or reduction” is the next step down from “aids in disease prevention.” A vaccine with this label claim should reduce disease severity and/or duration, says Clough. Keep an eye out for a label statement like this “as an aid in the control or reduction of disease due to (specific microorganism).”
Other miscellaneous claims, such as “reduction in pathogen shedding” may be granted. These claims will be granted if the effect is clinically significant and well supported by data, says Clough.
If a vaccine has multiple fractions, such as a 5-way viral vaccine, it will have multiple claims. For example, it could have “aids in disease prevention” for three viruses and “aids in control” for the other two. If the vaccine prevents against multiple disease syndromes, due to a single agent (such as respiratory disease and reproductive disease due to bovine viral diarrhea), the label will specify this, notes Clough.
Don’t expect a vaccine to perform above or beyond the scope of its label claim.
Dose and route of administration
Whether a single dose is required, or if a follow-up injection is required, the label will have the information. Keep in mind that vaccines often require two doses to achieve promised efficacy and immunity.
Follow the administration route indicated. Injectable products will be labeled either subcutaneous, intramuscular or both.
It is important to use a product promptly once it is opened. It is a common mistake to purchase a 50-dose bottle and use it for several weeks. “Once a vaccine bottle has been opened, you run the risk of bacteria contamination and deterioration of the vaccine contents,” notes Doug Braun, veterinarian with Pfizer Animal Health. Modified live vaccines may only be viable for a few hours after being reconstituted, and that time-frame can be less in warm weather. Killed products may last for a few days, but each product is different and no generalizations should be made.
Some companies will do studies to get a feel for how long an opened vaccine can be kept, but this will not be on the label, notes Clough.
Duration of immunity and necessary boosters
If a company has demonstrated a specific duration of immunity (DOI), it will be clearly spelled out on the product label. But, specifying a minimum duration of immunity is relatively new and not all products will have this information. If available, the statement will read similar to this: “A 12-month duration of immunity has been demonstrated against (specific microorganism).”
If DOI is not provided, the USDA default is an annual vaccination. Annual revaccination is not based on proven duration of immunity in this case, rather an approval to revaccinate every year. Be sure to consult with your herd veterinarian.
“It’s not uncommon for dairymen to use vaccines and never give booster injections or to identify the optimal revaccination intervals,” says Braun. “Sometimes, people don’t realize a booster is needed because they didn’t read the label or they do not want to spend the money or time to catch the animals.”
Building immunity is about using products correctly, not just vaccinating your animals. Be certain to follow label instructions to ensure the desired immunity for your herd.
If there are known age restrictions they will be indicated on the label. If a product says it should not be used on a certain age group, take it seriously.
The minimum age for use, if it is specified, corresponds to the age of the animals used to demonstrate the efficacy and safety of the product during the USDA licensing process. The performance of the product in younger animals is unknown. Minimum age is a fairly new piece of information on product labeling, and, on some products, no age restriction will be indicated. “No age restriction usually means the product was licensed before current labeling policies were implemented,” says Scott Nordstrom, director of dairy technical services for Intervet/Schering-Plough Animal Health. Rely on the expertise of your herd veterinarian to decide which age group is appropriate when none is indicated.
Keep in mind whether a vaccine is safe to use in pregnant cows. The label will indicate if it safe to vaccinate pregnant or open cows. If the label does not specifically mention pregnant animals, assume that the vaccine has not been evaluated for use in pregnant animals.
Expiration date and serial number
The expiration date indicates when a product is considered no longer effective, assuming proper handling and storage.
Expiration dates on vaccines are not like “drink by or sell by dates” on food. If a vaccine is used past its expiration date, it is unknown what, if any, level of protection it will provide, says Nordstrom.
Store vaccines according to the expiration date. Oldest vaccines should be in the front and short-dated products should be identified and specifically marked for quick use. If vaccine protocols change, then vaccines no longer used should be disposed of or returned for credit if applicable. Check with the manufacturer to see if they provide credit.
Serial numbers allow a product to be traced backwards to manufacturing. This is important if there is ever a product stop sale, recall or to report adverse events. Record the serial number of any vaccines used in your herd, notes Clough.
It is critical to follow storage guidelines indicated on a product’s label. All the scientific trials and data to prove the effectiveness of vaccines are based on the storage temperature indicated.
If you don’t store vaccines right or handle them properly, they won’t work, says Nordstrom. “Modified-live vaccines can be inactivated and become useless if mishandled, and killed vaccines can be damaged in a way that can harm the cattle injected.”
Read the packaging insert
It’s easy to toss aside the packaging insert that comes with the product, but there is a lot of good information on these. “Sometimes, the insert describes studies done in detail and provides actual numbers and information on the type of disease reduction,” explains Clough. Although companies are not required by the USDA to include this information, some do.
Regardless of which vaccines you decide to purchase consult with your herd veterinarian and ask the right questions to decide whether a vaccine fits into your herd-health plan.
What you can’t tell about a vaccine from its label
Although the label on a vaccine provides you with a lot of information, it will not tell you if the vaccine will work in your herd. The label is only one tool available in choosing a vaccine. (See “Ask before you buy.”)
In the last 10 years, there has been a trend toward more expansive label claims. If a vaccine was licensed some time ago, the label won’t necessarily have the same pieces of information.
Duration of immunity and minimum-age restrictions are both new additions to the labels. “We have not made manufacturers of older vaccines go back and prove duration of immunity or define a minimum age if there have been no reported problems. They have been grandfathered in,” says Nancy Clough, senior staff veterinarian with the USDA Center for Veterinary Biologics. Older products also are less likely to be labeled under the current standards for levels of protection, often defaulting to “aids in prevention of disease.”
Vaccines aren’t tested on every type of operation, on every age or breed of animal. And every test is not done under USDA guidelines; so the information can’t be put on the label. Therefore, you can’t learn everything there is to know about a vaccine from its label, but you can rely on the experience of your herd veterinarian for more information and insight on vaccines. Technical service veterinarians from animal-health companies can also be a resource of information.