Research and Discovery

Scientists develop concepts for a 

vaccine based on how the virus or 

bacteria causes disease in humans. 

They test their ideas in the laboratory.

Clinical Trials 

After FDA reviews the IND 

application, researchers test the 

safety and effectiveness of the 

vaccine in volunteers in phase 1, 

2, and 3 clinical trials. Each phase 

depends on the establishment of 

the safety of the vaccine candidate 

in the phase before it, involving 

more volunteers in each subsequent 

phase. By the time a vaccine reaches 

phase 3, it’s generally given to 

thousands of people, with those who 

receive the vaccine compared to 

those who receive a placebo.

FDA Review Staff

FDA carefully and thoroughly 

evaluates data and information 

about the vaccine. A typical FDA 

review team is comprised of 

physicians, chemists, statisticians, 

pharmacologists/toxicologists, 

microbiologists, experts in 

postmarketing safety, manufacturing 

and facility investigators, as well as 

labeling and communications experts.

Biologics License 

Application (BLA)

After phase 3 clinical trials meet 

specified milestones and the 

manufacturer develops a commercial 

manufacturing process, the 

manufacturer submits a BLA to the 

FDA. A BLA may be hundreds of 

thousands of pages or more and 

includes preclinical and clinical data, 

and details of the manufacturing 

process and the facility.

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Preclinical Research 

Before a vaccine is tested in 

humans, researchers do intensive 

safety and efficacy studies in the 

laboratory. Researchers also develop 

a vaccine manufacturing process to 

help ensure that research vaccines 

are sterile, pure, potent, and 

consistent from lot-to-lot. The FDA 

receives the results of the preclinical 

research and manufacturing 

information in an Investigational New 

Drug (IND) application.

Manufacturing

Vaccine manufacturing is complex. 

Manufacturers must develop 

a process to consistently and 

reliably produce thousands of 

vaccine doses. Before approval, 

the FDA works closely with vaccine 

manufacturers to develop the lot 

release protocol - a template of the 

tests that will be conducted for each 

lot (batch) of vaccine after approval. 

FDA Inspections

The FDA’s expert investigators 

inspect manufacturing facilities to 

carefully examine and evaluate the 

process used to make the vaccine 

to determine compliance with 

FDA’s requirements. Manufacturing 

facilities are inspected before a 

vaccine can be approved, and then 

on a routine basis following approval.

The Path for Vaccines

from Research to FDA Approval

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FDA Approval

The FDA evaluates hundreds 

of thousands of pages or more 

of data and manufacturing 

information as part of a BLA. If the 

FDA determines the vaccine is safe 

and effective for its intended use, 

that its benefits outweigh its risks 

for the people who are likely to get 

the vaccine, and the manufacturing 

process assures product quality 

and consistency, the FDA will 

“license” (or approve) the vaccine.

Vaccine Safety Surveillance 

The FDA, in collaboration with 

other federal agencies, academic 

and large non-government health 

care systems, uses both passive 

and active surveillance systems 

to monitor the safety of vaccines 

after approval. These systems 

include the Vaccine Adverse Event 

Reporting System (VAERS), the 

FDA Sentinel BEST (Biologics 

Effectiveness and Safety) program, 

a partnership with the Centers for 

Medicare and Medicaid Services 

to assess Medicare claims, and the 

CDC’s Vaccine Safety Datalink.

Lot Release

Manufacturers are not permitted 

to distribute a specific lot (batch) 

of vaccine until the FDA releases 

it. To release a vaccine lot, the 

FDA reviews the manufacturer’s 

test results that typically include 

vaccine sterility, purity, potency, 

and consistency, and may perform 

confirmatory testing.

Vaccines and Related Biological 

Products Advisory Committee 

(VRBPAC) 

Sometimes the FDA seeks the input 

of the VRBPAC, a federal advisory 

committee. VRBPAC is a panel of 

outside, independent, scientific and 

public health experts. The FDA 

considers, but is not bound by, the 

VRBPAC’s recommendations.

Prescribing Information and 

Labeling

Based on scientific data submitted 

in the BLA, the FDA reviews and 

determines whether the prescribing 

information adequately and 

accurately reflects the approved 

indication(s), usage, dosing, 

and administration. Prescribing 

information is updated as needed 

in order to include the most current 

information about the vaccine that is 

available and reviewed by the FDA.

Phase 4 Clinical Trials

In some cases the FDA requires 

a manufacturer to conduct postmarketing studies or Phase 4 

clinical trials to further assess 

known or potential serious risks of 

the vaccine.

FDA Regulatory Research

Ongoing research is fundamental 

to the FDA’s ability to provide 

effective vaccine regulation. FDA 

scientists conduct a variety of 

research that contributes to policy, 

risk assessments, new methods and 

standards, and changes to product 

labeling, including promoting new 

techniques for assessing vaccine 

safety, potency, and effectiveness 

in addition to strategies for new 

vaccine development.

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