603 LIVING / HEALTH
Understanding Vaccine Development The steps behind the COVID-19 vaccine
BY KAREN A. JAMROG / ILLUSTRATION BY GLORIA DILLANIN
T
he pandemic upended many aspects of daily life, including where we spend our time. Especially with telecommute arrangements likely to remain more common than they were prior to COVID, our home environments matter more than ever. And, while we like to think of home as a safe haven, mold, carbon monoxide, pesticides, insects, secondhand smoke and other factors can endanger health. Here we highlight a handful of common home hazards and offer tips to keep you and your family safe. It should help to know that, before a vaccine can be approved for use, it must
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undergo rigorous studies and testing that are designed to demonstrate safety and effectiveness. Typically, vaccine development starts in a lab, where scientists research and test their ideas. If a concept proves promising, they
eventually move forward with tests in animals to further investigate the safety and effectiveness of their potential vaccine, says Michael J. Gilbert, M.D., M.H.C.D.S., vice president of Medical Affairs and chief medical officer at Catholic Medical Center. Assuming animal tests go well, following a green light from the FDA, clinical trials in humans begin. Clinical trials consist of three or four phases. Phase one is small, with 20 to 100 healthy volunteers who receive the shot. “The first is the small study, a very intensive study that’s really to look at safety and entails a lot of consideration of potentially unexpected reactions,” says Peter F. Wright, M.D., an infectious disease physician at Dartmouth-Hitchcock Medical Center and professor of pediatrics at Dartmouth’s Geisel School of Medicine. Researchers keep close tabs on the volunteers after vaccination, “and if everything was progressing well, they would then open the study to a larger group of people,” Wright says. Subsequent phases of the clinical trials involve larger numbers of volunteers and include people who have underlying health conditions. By phase three, the vaccine under study is given to thousands of volunteers. Testing typically includes comparison with a control group, when some of the volunteers receive the vaccine, but others do not. Throughout each phase, researchers continue to gather data on the safety and effectiveness of the vaccine. A fourth phase occurs post-licensure or post-approval for emergency use and is an ongoing effort to study long-term risks and benefits of the vaccine, as well as occurrences, Wright says, such as the blood clots that have occurred in roughly one in a million people who have received the Johnson & Johnson COVID-19 vaccine. “You never can do a clinical trial before licensure that enables you to detect that kind of extraordinarily rare event,” he notes. Vaccines work by priming the immune system, Gilbert says. Some vaccines, such as the flu shot and the Johnson & Johnson
Although the Pfizer and Moderna COVID-19 vaccines are the first mRNA vaccines to be approved, scientists have studied and worked with mRNA for decades.
