Lifestyle Health Johnson & Johnson Pause Their COVID Vaccine Trials for Participant's 'Unexplained Illness' Pausing drug trials for an adverse reaction is a common practice to determine if the issue was caused by the vaccine dose or an unrelated problem By Julie Mazziotta Julie Mazziotta Twitter Julie Mazziotta is the Sports Editor at PEOPLE, covering everything from the NFL to tennis to Simone Biles and Tom Brady. She was previously an Associate Editor for the Health vertical for six years, and prior to joining PEOPLE worked at Health Magazine. When not covering professional athletes, Julie spends her time as a (very) amateur athlete, training for marathons, long bike trips and hikes. People Editorial Guidelines Published on October 13, 2020 11:40 AM Share Tweet Pin Email Patient receiving a vaccination. Photo: Getty Johnson & Johnson has paused its ongoing trials for a COVID-19 vaccine after a participant developed an “unexplained illness.” The pharmaceutical company did not say what the participant’s illness was, but explained in a statement that the temporary pause is “not uncommon in clinical trials.” During the course of vaccine or drug development, it is common practice to halt trials for an adverse participant reaction to determine if it was caused by the vaccine dose or due to an unrelated issue. “Adverse events — illnesses, accidents, etc. — even those that are serious, are an expected part of any clinical study, especially large studies,” Johnson & Johnson said. The pause occurs “so there can be a careful review of all of the medical information before deciding whether to restart the study.” Everything You Need to Know About a Coronavirus Vaccine The vaccine, one of the more promising options for the U.S., had entered its final stage of clinical trials on Sept. 23. It is the largest advanced vaccine trial so far, with 60,000 participants enrolled in their Phase 3 trials, and Johnson & Johnson had previously said it may be able to determine the vaccine’s effectiveness by the end of 2020. The vaccine was a standout option as it requires just one dose, unlike options from Pfizer and Moderna that are administered in two doses a month apart. Johnson & Johnson said that they are currently gathering information about the participant’s illness and will wait until they “have all the facts” before they share it publicly. They did not say if the participant had received the experimental vaccine or a placebo dose. “We must respect this participant’s privacy,” they said. RELATED VIDEO: Amanda Kloots, Widow of Nick Cordero, Calls Trump ‘Disgraceful’ for Minimizing Deadly Coronavirus Another promising vaccine, from AstraZeneca and the University of Oxford, was also put on hold last month after a participant from the United Kingdom reportedly developed a spinal cord injury. AstraZeneca resumed their trials in the U.K. on Sept. 12, but they are still waiting on approval from the Food and Drug Administration to begin again in the U.S. Andrew Lloyd Webber to Receive Experimental Coronavirus Vaccine as Part of Medical Trial With new COVID-19 cases again on the rise in the U.S., Americans are hoping for a vaccine to slow the spread of the highly contagious virus. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, has said he is “cautiously optimistic” that the U.S. will be able to identify a safe and effective vaccine by the end of 2020, with distribution in 2021. Fauci added, though, that even with a vaccine, Americans will have to keep up COVID-19 precautions like masking, hand washing and social distancing. “A combination of an effective vaccine and adherence to certain public-health principles will get us to the point where we want to be, by the end of 2021,” he told Business Insider in September. As information about the coronavirus pandemic rapidly changes, PEOPLE is committed to providing the most recent data in our coverage. Some of the information in this story may have changed after publication. For the latest on COVID-19, readers are encouraged to use online resources from the WHO and local public health departments. PEOPLE has partnered with GoFundMe to raise money for the COVID-19 Relief Fund, a GoFundMe.org fundraiser to support everything from frontline responders to families in need, as well as organizations helping communities. For more information or to donate, click here.