Here’s How Vaccine Shelf Life Can Be Safely Extended

The Food and Drug Administration (FDA) recently authorized a second extension of the Johnson & Johnson COVID-19 vaccine's shelf life. 

Back in June, the shelf life of the vaccine was extended to 4.5 months. As ongoing stability assessment studies have demonstrated, the vaccine remains potent for six months.

Many have questions about how a vaccine’s expiration date can be extended and are expressing worry about the doses’ safety and effectiveness. However, the FDA authorization of the extension indicates that the doses' quality remains the same.

The Process of Determining a Vaccine’s Expiration

“Vaccine production occurs under strict oversight by regulators—the FDA—and quality assurance programs,” Naor Bar-Zeev, PhD, deputy director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, tells Verywell. 

The FDA has well-established regulatory standards to ensure the quality of pharmaceuticals and drug products, which includes vaccines. The agency performs numerous stability assessments to determine how long a particular drug product can remain safe and effective, which is known as its shelf life.

“Shelf life is determined by checking potency and concentration of substances within any given pharmaceutical product,” says Bar-Zeev. “The shelf life of different vaccines differs on the basis of their ingredients and manufacturing process.”

According to Crystal Tubbs, PharmD, the associate director in the department of pharmacy at The Ohio State University Wexner Medical Center, every drug product is unique. The main areas in which products differ include:

• Chemical and physical properties of the active ingredients or the excipients
• Manufacturing procedures
• Formulations
• Containers and closures
• Proposed storage conditions
• The ability to maintain quality or purity through the use of antioxidants or preservatives

“Because of the uniqueness of each drug product, it is virtually impossible to provide one set of rules that can apply to all situations,” says Tubbs. This is why different brands of COVID-19 vaccines have varying expiration dates and storage requirements.

For example, when refrigerated at 36 to 46 degrees Fahrenheit, the Moderna mRNA vaccine can only be stored for up to 30 days, while the Johnson & Johnson viral vector vaccine remains stable for six months.

How Is a Vaccine’s Shelf Life Extended?

When vaccines are developed, manufacturers continue to perform stability assessment studies to ensure ongoing monitoring of how long the vaccines will remain safe and effective for use.

With each passing month, scientists are given a longer period in which to evaluate vaccines in real-time, allowing them to observe if a vaccine's shelf life can be extended.

“To extend the expiration date of a vaccine, the product would need to meet the same requirements that established the original expiration date,” says Tubbs. “Since we have the opportunity to study the vaccines over longer periods of time, it is not a surprise that expiration dates have been extended.”

It might seem confusing that Johnson & Johnson has already extended their COVID-19 vaccine’s shelf life twice. However, these extensions are based on rigorous scientific data that the FDA has thoroughly reviewed. If there were any concerns about the vaccine's safety or effectiveness, or if it posed additional risks, the FDA would not authorize an extension.

According to Tubbs, it’s possible that we may see other vaccines extend their indicated shelf life as well, because "we have longer periods of time to study and evaluate the drug products in their final formulations, it would not be unusual to see an extension of the expiration dates moving forward."

Are Nearly-Expired Vaccines Still Safe?

Tubbs says that the Johnson & Johnson vaccine doses that were almost expired remain safe and effective because “the same standards for sterility and stability must be met in order to extend the expiration date."

That means that the results of stability studies demonstrated that the vaccine remains potent for one and a half more months, bringing the shelf life to six months.

While you might feel that you would prefer to be vaccinated with doses that are far from expiration, you should know that those doses are no different than the nearly expired ones. All are similarly safe and effective at preventing severe COVID-19 disease.

“Expired products may not be used, but products that have not yet expired are potent and effective,” says Bar-Zeev. “Products that are closest to expiration should be used first. This is the recommendation of the WHO for all pharmaceuticals in all settings.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.