AstraZeneca may have provided an incomplete view of the efficacy data related to its COVID-19 vaccine clinical trial, the National Institute of Allergy and Infectious Diseases (NIAID) said on Tuesday. 

The British pharmaceutical company first published a statement early Monday, saying the Phase III trial of its COVID-19 vaccine — which was conducted in the U.S. — showed a 79% effectiveness in preventing symptomatic infections and a 100% efficacy "at preventing severe disease and hospitalization."

Later Monday, the Data and Safety Monitoring Board [DSMB] notified AstraZeneca, NIAID and the Biomedical Advanced Research and Development Authority [BARDA] that it was concerned about information released by the company on initial data from its COVID-19 vaccine clinical trial, the NIAID wrote in a statement

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"The DSMB expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data," according to the statement. "We urge the company to work with the DSMB to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible."

March 10, 2021: Health workers administer doses of the AstraZeneca vaccine against COVID-19 inside the convention center known as "La Nuvola", The Cloud, in Rome.

March 10, 2021: Health workers administer doses of the AstraZeneca vaccine against COVID-19 inside the convention center known as "La Nuvola", The Cloud, in Rome. (AP Photo/Andrew Medichini)

In response, the company acknowledged on Tuesday that the numbers included in the published study results "were based on pre-specified interim analysis with a data cut-off of 17 February." 

"We have reviewed the preliminary assessment of the primary analysis and the results were consistent with the interim analysis," AstraZeneca said in an updated statement. "We are now completing the validation of the statistical analysis. We will immediately engage with the independent data safety monitoring board (DSMB) to share our primary analysis with the most up to date efficacy data." 

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The company said it expects to "issue results of the primary analysis within 48 hours." 

The request to review efficacy data comes as the company plans to seek U.S. Emergency Use Authorization for the vaccine in the coming weeks. 

Authorization and guidelines for use of the vaccine in the U.S. will be determined by the Food and Drug Administration [FDA] and Centers for Disease Control and Prevention [CDC] after a "thorough review of the data by independent advisory committees," according to the statement. 

This week, AstraZeneca U.S. President Ruud Dobber said the company will be able to provide 30 million doses for Americans once the vaccine receives EUA. 

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Dobber recently sought to assure the American public that the company’s COVID-19 vaccine was safe after several European countries temporarily stopped using it due to instances of blood clots in jab recipients. A safety committee with Europe's regulatory agency later concluded that the vaccine is safe and effective, with no ties to an overall increased risk of blood clots in vaccinated individuals. 

The U.S.-based trial also found "no increased risk" of blood clots. 

Fox News' Edmund DeMarche and Fox Business' Brittany De Lea contributed to this report