Pfizer identifies counterfeit COVID-19 vaccine in Mexico, Poland; warns of increase in fraud • 6 min read Woman who experienced blood clots after taking J&J vaccine in recovery Johnson & Johnson’s COVID vaccine is on hold in the U.S. as experts investigate cases of rare blood clots that affected six women.Frederic J. Brown/AFP via Getty Images Counterfeit versions of Pfizer's COVID-19 vaccine have been identified in Mexico and Poland, a Pfizer spokesperson confirmed to ABC News -- adding to the running tally of scam attempts in the U.S. and internationally. "We are cognizant that in this type of environment -- fueled by the ease and convenience of e-commerce and anonymity afforded by the Internet -- there will be an increase in the prevalence of fraud, counterfeit and other illicit activity as it relates to vaccines and treatments for COVID-19," the spokesperson told ABC News.