Frequently asked questions

Frequently asked questions

Drug or vaccine development is the journey from an idea for a potential medicine or vaccine all the way through to bringing that new medicine or vaccine to patients who need it. The development lifecycle includes laboratory research and a series of clinical trials in people. Along the way, important information is collected about the potential medicine or vaccine and how it affects clinical trial participants. If that information shows the potential medicine or vaccine is safe and effective, clinical trial sponsors provide the information to regulatory authorities, which decide whether to approve the medicine’s or vaccine’s use by patients.

Clinical trials (or research studies) are a type of medical research in which people volunteer to take part. Clinical trials commonly study how potential medicines and other medical treatments affect the participants.

All medicines and vaccines that become available today for use in patients are first tested in clinical trials involving hundreds to thousands of people.

What happens in a clinical trial depends on the ‘protocol.’ A protocol is a detailed plan that explains the purpose of the clinical trial and how it will be run. If you consider joining a clinical trial, these details will be explained to you as part of the informed consent process

They include:

  • the length of the clinical trial
  • the study medicines, procedures, and tests in the clinical trial
  • the schedule of study activities
  • information about who can participate
  • how side effects will be tracked, managed, and reported
  • the rules that must be followed

A clinical trial may also have aspects such as randomisation, placebo, or blinding.

  • As part of a clinical trial, your study-related medical care is provided by the study team at the location where you’re participating. This includes the principal investigator (or study doctor) — the healthcare  professional who conducts and takes responsibility for the trial at that location — as well as other clinical  study team members.

  • During your clinical trial, you may also continue to see your regular medical doctors for any care that is not related to the study. It is important for you to tell your study team about other conditions you might have, and to let them know which other doctors are caring for you. This helps the study team coordinate your overall care.

  • If you participate, the clinical trial will provide study-related medical care, and your regular medical doctors will address the other aspects of your health. Your regular medical doctors can also work with the study team to understand the details of the study and any impact it may have on your regular medical care.

All clinical trials have possible risks. The known and unknown risks of participating in a specific study will be explained to you during the informed consent process that happens before you decide whether to participate.


Clinical researchers must follow guidelines and regulatory requirements to help protect the rights, safety, and well-being of clinical trial participants. These include Good Clinical Practice (GCP). GCP is an international ethical and scientific quality standard for designing and conducting clinical trials.


There are also many entities that provide oversight of clinical trials. These include health authorities or regulators, institutional review boards and independent ethics committees, and data safety and monitoring boards.

We encourage everybody to consider joining clinical trials. There are many types of clinical trials that study different aspects of health in people with a variety of backgrounds and conditions. Each clinical trial has its own criteria for who may participate. These are called eligibility criteria.


Eligibility criteria include things like your age, sex, overall health, type of condition, and your medical treatment history. As part of the steps to join a clinical trial, the study doctor will confirm whether you meet all eligibility criteria and are able to participate.
Participation in a clinical trial is always voluntary. The decision to join is personal, and it is yours.

Pfizer generally covers the cost of the study medicines and procedures that are part of our clinical trials.


Pfizer is also committed to reimbursing participants for reasonable clinical trial-related expenses such as transportation, parking, and meals.


Because each study is different, we encourage you to ask the study team any questions you have. You can also refer to the informed consent document for the details about any costs for study participants and study-related reimbursement.




How clinical 

trials work

Steps to join 

a clinical trial


your safety 

& privacy