The UK health department's medicines division will approve British-Swedish pharmaceutical company AstraZeneca plc's COVID vaccine as soon as Tuesday, officials said.

The company says its vaccine is effective in fighting the new coronavirus strain in the UK. Chief executive officer Pascal Soriot says the vaccine "remains effective."

AstraZeneca's vaccine is expected to be approved for public use this week. UK officials confirmed Monday that the Medicines and Healthcare Products Regulatory Agency would likely give its OK for use Tuesday.

Soriot said the company had discovered a "winning formula" that makes its vaccine as effective as those produced by Pfizer Inc. and Moderna, Inc. The vaccines produced by the American companies have both been approved there.

"So far, we think the vaccine should remain effective. But we can't be sure, so we're going to test that," Soriot said when asked about AstraZeneca's efficacy against the new strain.

AstraZeneca developed its vaccine in partnership with Oxford University. Initial reports suggested it was likely not as effective as those produced by American companies. Partial test results suggested that it was around 70% effective only.

The UK was the first Western government to approve mass inoculations using Pfizer's vaccine. As of Dec. 24, more than 600,000 people had been vaccinated.  

Last week, Moderna said that its vaccine was effective in the new strain. Pfizer said its vaccine should neutralize the new strain and any other mutations. The company said its technology was the ideal treatment to combat rapidly mutating viruses.

Earlier this month researchers discovered a new strain of the virus in samples from southern England.

Preliminary findings suggest that strain is more contagious and can spread more quickly. However, the new strain is not believed to be more deadly and the symptoms it causes are more or less the same.

Epidemiologists at Imperial College London estimate the strain has an increased transmission rate of up to 70% when compared with other variants.