LONDON (AP) — U.K. regulators went on the offensive Friday to beat back criticism that they rushed their authorization of a COVID-19 vaccine, saying they rigorously analyzed data on safety and effectiveness in the shortest time possible without compromising the thoroughness of their review.

The comments from the Medicines and Healthcare Products Regulatory Agency came as the Times newspaper reported that the agency’s chief executive, Dr. June Raine, planned to give a series of radio interviews so she could speak directly to people who may be concerned about getting vaccinated.

The MHRA reiterated earlier statements that the agency is conducting rolling reviews of COVID-19 vaccine candidates, allowing regulators to speed up the review process by looking at data as it becomes available. The agency gave emergency approval on Wednesday to a vaccine produced by U.S. drugmaker Pfizer and Germany-based BioNTech, making Britain the first Western country to authorize a vaccine against the coronavirus.

The ability to act more quickly “does not mean steps and the expected standards of safety, quality and effectiveness have been bypassed,” the MHRA said. “No vaccine would be authorized for supply in the U.K. unless the expected standards of safety, quality and efficacy are met.”

The media blitz comes amid concerns that criticism of the approval process could undermine public confidence in the Pfizer/BioNTech vaccine, leading some individuals to shun shots. Britain plans to begin vaccinating people within the next few days, starting with nursing home residents, caregivers and people over age 80.

Britain will initially receive 800,000 doses, enough to vaccinate 400,000 people, so the first shots will go to those who are most at risk of dying from COVID-19 and those who are most likely to spread the coronavirus.

America’s top infectious disease expert late Thursday apologized for suggesting that U.K. authorities had rushed their authorization of the vaccine.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, had told U.S. media outlets that U.K. regulators hadn’t acted “as carefully” as the Food and Drug Administration. He later clarified to the BBC that he had meant to say that U.S. authorities do things differently than their British counterparts, not better, but didn't phrase his comments properly.

“I do have great faith in both the scientific community and the regulatory community at the U.K., and anyone who knows me and my relationship with that over literally decades, you know that’s the case,” Fauci told the BBC.

Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, said the different approaches of various regulators may be one reason Britain was first to authorize the vaccine.

The FDA, for example, goes back to the raw data supplied by drugmakers and reanalyzes it to verify the findings. Virtually no other regulatory agency regularly does this, said Evans, who has worked with regulators in the U.K. and the European Union.

In addition, Britain decided to take advantage of EU rules that allow individual countries to allow the emergency use of new products inside their own borders in response to public health emergencies. The EU's European Medicines Agency chose a more time-consuming authorization process that will allow the vaccine to be used in all 27 member nations.

While Britain left the European Union on Jan. 31, it remains bound by the bloc’s rules and regulations until the end of December under a transition agreement designed to ease the shock of Brexit.

Brexit helped the Medicines and Healthcare Products Regulatory Agency move faster because it is no longer involved in assessing products intended for the entire bloc as are regulators in the remaining EU countries, according to Evans. MHRA therefore had more resources to devote to the Pfizer/BioNTech vaccine and could respond more quickly when new data was submitted, he said.

“Consequently, the U.K. has almost undoubtedly had greater capacity to respond to a new application for authorization of a vaccine than any other country,” Evans said.

When the MHRA announced its decision on the Pfizer/BioNTech vaccine, chief executive Raine said people should be confident “no corners have been cut.” British experts reviewed more than 1,000 pages of information, including raw data, on safety, quality and effectiveness before deciding to give temporary authorization for use of the vaccine, she said.

But European officials reacted sourly to the U.K. decision.

The European Medicines Agency, which plans to make its own decision by Dec. 29, issued a statement saying its process was “more appropriate” than Britain’s.

Bavarian Governor Markus Soeder was more pointed, suggesting U.K. authorities had acted “without even sufficient basis.”

“This will reduce the readiness to get vaccinated rather than increase it, because people expect a safe immunization process,” he said.

In his latest comments, Fauci rejected the idea that the U.K. skipped vital steps.

The FDA has to move more slowly amid the high degree of skepticism about vaccines in the U.S., Fauci said. Because of this, U.S. regulators are reviewing all of the raw data from Pfizer and BioNTech “in a way that could not possibly have been done any more quickly,” he said.

It will take the FDA at least another week to complete its review, but the U.S. and Britain will ultimately end up in the same place, Fauci said.

“At the end of the day, it’s going to be safe, it’s going to be effective,” he said. “The people in the U.K. are going to receive it, and they’re going to do really well, and the people in the United States are going to receive it, and we’re going to do pretty well.”

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Associated Press Writer Frank Jordans contributed.

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