Pfizer warns of increase in fraudulent vaccines as fake doses found overseas Woman who experienced blood clots after taking J&J vaccine in recovery Replay Video UP NEXT 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.