This September 2020 photo provided by Johnson & Johnson shows vials for a single-dose COVID-19 vaccine being developed by the company. Credit: (Cheryl Gerber/Johnson & Johnson via AP) Doses of the Johnson & Johnson vaccine are still on temporary hold after dangerous blood clots were found exclusively in women. Experts are urging scientists to do more research so it doesn’t happen again. “The CDC and the FDA are reviewing data involving six reports of a rare type of blood clot called cerebral venous sinus thrombosis or CVST – in combination with low levels of platelets in the blood, called thrombocytopenia, in women ages 18 to 48,” said Dr. Peter Marks, Ph.D., director of the Center for Biologics Evaluation and Research at the Food and Drug Administration. The women’s reactions were a surprise for the public, but for experts like Dr. Saralyn Mark, women’s health specialist with the American Medical Women’s Association, “I anticipated that we would be seeing differences in regard to vaccine safety and efficacy.” Even a Government Accountability Office report from decades ago found that eight out of 10 recalled drugs posed greater health risks for women. That’s why Mark is frustrated women had to suffer. “We all know too well, unless something terrible happens, we often don’t draw attention to the issues.” That attention can bring change. “We are learning as we’re going along. And that’s not necessarily a bad thing. It becomes a bad thing when we don’t respond to the data that we gather,” Mark said. “What we may find is that women may do just as well with a smaller dose, may have less side effects.” Mark said federal health leaders should use this as an opportunity to start breaking down COVID-19 clinical trial data by age and sex. RELATED Report by Dr. Saralyn Mark: Viewing the COVID-19 Pandemic Through a Sex and Gender Lens