COVID-19 vaccine studies may suffer as volunteers consider dropping out

As part of their development efforts for a COVID-19 vaccine, researchers at Pfizer and Moderna scheduled 2-year trials and had no plans to inform volunteers if they received a vaccine candidate or placebo until the conclusion of the studies. Subjects agreed to the terms upon signing up, but experts say participants may leave the trials at any time. However, early exits could impede the collection of data to fully evaluate the vaccines’ safety and duration of effectiveness. More than 100 vaccine-study participants recently wrote to FDA requesting the agency to encourage companies to notify them if they received a placebo and be eligible for an authorized vaccine. Arnold Monto, MD, a University of Michigan health researcher who heads a panel of experts that will advise the FDA about authorizing COVID-19 vaccines, said: “Frankly, people should not have gone into this study who didn’t feel they could wait.” Monto points out that many volunteers who received a placebo will likely not be eligible for vaccine supplies for some time. Globally, about 48 COVID-19 vaccines are being tested in people, according to the World Health Organization. As companies release data from their late-stage vaccine trials, some study subjects are taking antibody tests to see whether they received the vaccine or placebo. In October, Johnson & Johnson expressed concern to a committee of independent experts advising the FDA on vaccines that clearance of the first vaccine would compromise other companies’ ability to recruit and retain volunteers for their own studies.