COVID-19 | Oct. 6, 2021

Vaccine Development FAQs

Q. What are the ingredients in COVID-19 vaccines?
A. Besides the active ingredients which help the body produce a protective immune response against the COVID-19 virus, depending on the vaccine, inactive ingredients include small amounts of polyethylene glycol, polysorbate 80, sodium chloride (salt), potassium chloride (salt substitute), sucrose (sugar), and citric acid (vitamin C). A full listing of ingredients is available at Interim Clinical Considerations for Use of COVID-19 Vaccines | CDC.

None of the vaccines contain eggs, gelatin, latex, or preservatives. All COVID-19 vaccines are free from metals or any manufactured products such as microelectronics, electrodes, carbon nanotubes, or nanowire semiconductors.


Q. What are the different types of COVID-19 vaccines?
A. As COVID-19 vaccines are authorized and then recommended for use in the United States, it’s important to learn about the vaccines that are available.  The CDC provides information on who is eligible and recommended to receive each vaccine and what to expect after vaccination, as well as ingredients, safety, and effectiveness.  To read more from the CDC about the different COVID-19 vaccines, please read this CDC article. Currently, three vaccines are authorized (under an Emergency Use Authorization) and recommended to prevent COVID-19:


Additionally, Pfizer-BioNTech (COMIRNATY) received U.S. Food and Drug Administration (FDA) approval on August 23, 2021, for individuals 16 years of age and older. The FDA-approved Pfizer-BioNTech product Comirnaty (COVID-19 Vaccine, mRNA) and the FDA-authorized Pfizer-BioNTech COVID-19 Vaccine under EUA have the same formulation and can be administered interchangeably to provide the COVID-19 vaccination series. 

Q. How was the COVID-19 Vaccine developed so rapidly, in record time?
Due to the urgency and critical need to produce the vaccine and provide it to the public safely and quickly, our country expended every resource and made development and testing of COVID-19 vaccines a top priority. Authorization to use the vaccine came quickly because the Food and Drug Administration (FDA) accelerated the vaccines to the front line at every step. No compromises on safety or effectiveness were made during their development.

According to the Centers for Disease Control and Prevention (CDC), developing a vaccine and bringing it to market often takes many years. But because of work that the National Institutes of Health (NIH) was already doing when the COVID-19 pandemic began, researchers were able to come up with vaccines for this new virus much more quickly. You can read more about the COVID-19 vaccine development effort here: COVID-19 Vaccine Development: Behind the Scenes.


Q. What is an Emergency Use Authorization?
A. Drugs and vaccines have to be licensed or authorized by the U.S. Food and Drug Administration (FDA) to ensure that only safe and effective products are available to the American public. In situations when there is strong scientific evidence that a product is safe and is likely to treat or prevent disease, the FDA may authorize its emergency use under specific circumstances.

This type of FDA pre-licensure approval is considered for treatment or prevention of diseases that are very serious and occurring during an outbreak or pandemic scenario. For the COVID-19 vaccines, the Emergency Use Authorization (EUA) indicates that the FDA has found the vaccine to be safe, however, studies regarding the full duration of protection against disease will continue.

Pharmaceutical manufacturers choose whether to make a request for EUA or routine licensure based upon the circumstances. The processes used to evaluate the current COVID-19 vaccines for their safety and effectiveness were no less rigorous than if the manufacturers had requested an adjudication for a licensed vaccine. EUAs are permitted only during emergent circumstances.


Q. How is an Emergency Use Authorization (EUA) different from full approval?
A. According to the Food and Drug Administration (FDA) Emergency Use Authorization (EUA) announcement, the issuance of an EUA is different than an FDA approval (licensure) of a vaccine. The FDA is able to grant a special type of interim approval called an EUA during public health emergencies. Just like full approval/licensure, an EUA looks at the totality of data and does a risk-benefit analysis. The FDA does a rigorous safety analysis and then looks at the how effectively the vaccine is at preventing disease in the context of a pandemic, when the disease is widespread and many people are routinely being infected.

If issued an EUA, vaccine manufacturers are obligated under FDA rules to continue their clinical trial monitoring and gather more data to fully understand how long the vaccine protection will last. Additionally, the FDA and Centers for Disease Control and Prevention (CDC) collect reports from those who receive the vaccines to develop the best understanding of common side-effects.