More than a billion dollars worth of Pfizer’s COVID-19 antiviral drugs procured in Europe have been wasted, according to health data, as tight controls over who can receive the medication left millions of doses unused before their expiry date, Report informs via the Financial Times.

Paxlovid — designed to be given to patients shortly after they test positive for the virus — has been far easier to obtain in the US than in Europe, where access has often been restricted to the elderly or people at high risk of developing severe Covid.

But data from analytics group Airfinity shows European countries including the UK, France, Spain and Italy could have made the medication more accessible without using up supplies, as more than 1.5 million five-day courses of the pill worth about $1.1 billion have expired despite their usage dates being extended by six to 12 months.

By the end of February 2024, a total of about 3.1 million courses are set to expire, pushing the cost to European health systems to about $2.2 billion, according to Airfinity. The data does not include contracts that were EU-wide.

Marco Gallotta, an analyst at Airfinity, said some countries may have overpurchased Paxlovid when it became available at the end of 2021, just as the Omicron variant increased global caseloads.

“Governments were keen to buy the highly efficacious antiviral and had a difficult challenge of estimating demand with so many unknowns,” he said.

But a drop in cases and a sharp reduction in testing had hit the take-up of antiviral drugs, which needed to be taken shortly after the onset of symptoms, he said. “This means countries haven’t been able to administer all of their stockpiles before they expire, despite extensions to the shelf life.”

Pfizer said: “Expiry and destruction of doses can be an unavoidable consequence of a pandemic, a natural result of manufacturers and governments collectively aiming to address the public health crisis at speed with the overarching objective of protecting their populations.”

There have also been concerns over how Paxlovid interacts with other common medications, which restricts how often it can be prescribed.

The European country with the biggest expiry rate is the UK, where an estimated 1 million doses worth $700 million were out of date by early December, the data shows. Another 550,000 doses are expected to expire in February, with a further 650,000 by the end of June.