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How vaccines get made and approved in the US

  • How vaccines get made and approved in the US

    COVID-19 and its wide-ranging impacts on the lives of nearly everyone on the planet have brought vaccines to the forefront—if a suitable vaccine can be found and widely distributed, then life could perhaps resume some semblance of normalcy. People around the world are waiting impatiently for news of vaccine trials from companies such as Pfizer, Moderna, and AstraZeneca.

    Already there have been some promising developments. On Nov. 16, Moderna released the results of a study that showed their vaccine has a 94% rate of effectiveness. While the results of their 30,000-person Phase 3 trial have not yet been published, researchers said that the results show that the vaccine is safe and effective. On Nov. 18, Pfizer and its partner BioNTech announced it concluded its Phase 3 study (which began July 27) and determined their vaccine is 95% effective. Pfizer and BioNTech will submit a request for Emergency Use Authorization by the FDA as soon as possible and plans to share their data with global regulatory agencies.

    On Nov. 23, AstraZeneca also released early results from its Phase 3 vaccine trial, conducted in partnership with the University of Oxford. AstraZeneca's vaccine has so far demonstrated an average 70% effectiveness rate—while not as impressive as Pfizer and Moderna, this rate still meets the FDA's requirements for authorization.

    The news from all three companies has given people hope that the SARS-CoV-2 virus that causes COVID-19 can eventually be controlled. However, there is also mistrust surrounding vaccines, and often a lack of understanding about how they are created, how they are tested, and how safe they are. If people don’t trust the vaccine, then people won’t take it, and the pandemic could go on longer.

    Some of this lack of trust comes from a lack of information or misinformation. In order to demystify vaccines and the vaccine manufacturing and approval process in the United States, Stacker consulted the Food & Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and other public health sources to better understand and explain vaccines to the general public.

    After going through these authoritative health information sources, Stacker identified some key terms to help readers better understand the types of vaccines and how they work, and then listed the many steps involved in the creation, approval, and distribution of new vaccines in the U.S. We then created a list of 30 key terms and steps, showing how intensive and precise the vaccine creation and approval process is, and ultimately that vaccines are safe and effective tools for fighting disease.

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  • U.S. Food & Drug Administration (FDA)

    The U.S. Food and Drug Administration (FDA) protects public health by ensuring the efficacy and safety of biological products, including food and drugs such as vaccines. This means that for any vaccine to be approved for distribution to the American public, it must first be approved by the FDA.

  • Center for Biologics Evaluation and Research

    The specific area of the FDA that deals with vaccines is the Center for Biologics Evaluation Research (CBER). This center regulates biological products using an array of regulatory measures, such as the Public Health Service Act and the Food Drug and Cosmetic Act.

  • Identifying an antigen

    The process to create a vaccine is historically a long one. It begins with scientists and researchers identifying the antigen, which is the part of a germ that the immune system can recognize and attack to prevent the targeted disease.

  • Stimulating the immune system

    Vaccines work by stimulating a reaction from the immune system. They do this by essentially tricking the body into thinking there’s an infection. While the body may occasionally experience minor symptoms of infection after getting a vaccine, the kind of pseudo-infection introduced by the vaccine almost never causes illness.

  • Whole-pathogen vaccines

    Whole-pathogen vaccines are the traditional type of vaccine. These vaccines contain entire pathogens that have either been killed or weakened enough that they cannot cause disease. Because they have whole pathogens, they elicit strong immune responses. However, not every disease can be targeted with this type of vaccine.



  • Subunit vaccines

    Unlike a whole pathogen vaccine, a subunit vaccine uses just the antigens to best stimulate the immune system. This vaccine design is safer and easier to produce, but it often requires the addition of adjuvants, components that elicit a stronger immune response, because the antigens are not sufficient on their own for long-term immunity.

  • Nucleic acid vaccines

    Nucleic acid vaccines use genetic material to encode the antigen or antigens needed to produce an immune response from the body. This allows the body’s own cells to produce the antigen(s) using the genetic material. The advantages to this type of vaccine are long-term immune responses, scalability, and vaccine stability. Some of these vaccines are based on mRNA (messenger DNA). Both the Pfizer/BioNTech and Moderna coronavirus vaccines use mRNA.

  • Multiple-dose vaccines

    Some vaccines require more than one dose. There are a few reasons for this. Some vaccines do not provide much immunity in the first dose, and therefore need more. In others, immunity wears off after time, and “booster” doses are needed. In some live vaccines, multiple doses make it more effective. And in the case of the flu vaccine, a new dose is needed every year because the flu virus that causes the disease varies year to year.

  • Screening for potential danger to animals

    Before beginning an Investigational New Drug (IND) application, a vaccine must be screened for potential danger to animals. These take place through animal pharmacology and toxicology studies, taking preclinical data to allow an assessment as to whether the product is safe enough to begin testing in humans.

  • Investigational New Drug application

    Once the screening for potential danger to animals is completed satisfactorily, the vaccine goes through the IND. The IND allows the vaccine sponsor to obtain permission from the FDA to distribute the vaccine across state lines to clinical investigators. At this point, the molecule being used in pharmacological activity changes legally into a new drug.