Two health workers, who are understood to both have a history of severe allergic reactions, were among thousands to receive the vaccine on the first day of the Covid-19 mass vaccination programme.
The EMA declined to provide more details of the attack while the investigation was continuing, but the two companies later released a statement saying that "some documents relating to the regulatory submission for Pfizer and BioNTech's COVID-19 vaccine candidate, BNT162b2, which has been stored on an EMA server, had been unlawfully accessed".
A participant in the clinical trial of the coronavirus vaccine developed by Pfizer and BioNTech urged a panel of outside experts Thursday to recommend that the Food and Drug Administration immediately authorize it for emergency use.
Dr. Fink also addressed one major topic that has been in question-whether patients in the Pfizer trial who were randomly assigned to placebo should automatically be switched over and get the vaccine.
FDA consent could come as early as Friday or Saturday, followed by the first US injections on Sunday or Monday, Moncef Slaoui, chief adviser to the Trump administration's Operation Warp Speed vaccine development program, told Fox News.
The warning was issued after three people who received the vaccine suffered from allergic reactions.
She noted the agency is "aware of" the decisions by the United Kingdom and Canada to approve the BioNTech/Pfizer vaccine with the faster process of an emergency authorization.
"So people still have to be careful despite having had one dose of the vaccine, as maybe only half of those might be protected - until the second dose has been given". "EMA has assured us that the cyber attack will have no impact on the timeline for its review".
The vaccine is administered into the body and enters cells, instructing the cells to produce coronavirus spike protein. Vaccines from AstraZeneca Plc and its partner University of Oxford as well as Johnson & Johnson could become available next year. But full protection may not happen until a couple weeks after the second shot.
The results described in company and FDA analyses earlier this week showed the vaccine's effectiveness hovered around 95% in all ages and ethnic groups. FDA staff said the shot prevents symptoms of COVID-19 but may not be as good at preventing infections that don't show symptoms, meaning significant transmission would still be possible without basic health measures.
"What appears to be a dramatic success for vaccination holds the promise of saving uncounted lives and giving us a pathway out of what has been a global disaster", wrote Eric Rubin, editor-in-chief of the journal, and Dan Longo, the deputy editor.