New York, Mar 23 (IANS): Following the doubts expressed by a top US-based health agency over the Covid-19 vaccine trial data, British-Swedish drugmaker AstraZeneca on Tuesday said that it will share primary analysis of its vaccine with the most up-to-date data, with the independent Data and Safety Monitoring Board (DSMB), which reviewed the trial results.

The drugmaker, which showed that its vaccine's efficacy is 79 per cent in preventing symptomatic illness in a large trial in the US on Monday, said that the data published were based on a 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. We are now completing the validation of the statistical analysis," the company said in a statement.

"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. We intend to issue results of the primary analysis within 48 hours," it added.

In an earlier statement on Tuesday, the US-based National Institute of Allergy and Infectious Diseases (NIAID) expressed concern that AstraZeneca may have provided outdated information on the efficacy data related to the clinical trial of its Covid-19 vaccine, which may have provided an incomplete view of the efficacy data.

On Monday, the drugmaker showed that its vaccine's efficacy is 79 per cent in preventing symptomatic illness in a large trial in the US.

However, in an unusual statement, the independent Data and Safety Monitoring Board (DSMB), which reviewed the trial results, notified NIAID, Biomedical Advanced Research and Development Authority (BARDA), and AstraZeneca that it is concerned over the information released by AstraZeneca on the initial data from the clinical trial of its Covid-19 vaccine.

"We urge the company to work with the DSMB to review the efficacy data and ensure that the most accurate, up-to-date efficacy data is made public as quickly as possible," the US-based agency said.

"Authorisation and guidelines for use of the vaccine in the US will be determined by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) after a thorough review of the data by independent advisory committees," it added.

Earlier, the Phase III AstraZeneca trials in the US showed an efficacy of 80 per cent in people over the age of 65, the most vulnerable group for contracting Covid-19 with deadly consequences. Twenty per cent of the trial participants were over the age of 65.

The vaccine, known by the scientific name 'AZD1222', was 100 per cent effective in preventing hospitalisation, the company had said in a statement.

It means that even those who contracted Covid-19 after vaccination had only less severe symptoms and did not need intensive treatment in a hospital.