The pound had its best quarter against the euro since 2015 in the first three months of 2021, boosted by the UK's vaccine rollout, which is one of the fastest in the world, as well as a fading of negative interest rate expectations.
Versus the dollar, the pound was down 0.1% at $1.3723, and also on track for a weekly loss.
The pound fell 1.2% against the dollar and 1.7% against the euro between Tuesday and Wednesday as investors took cash off the table after a strong first quarter for the British currency.
Sterling's pullback was "exaggerated," ING analysts wrote, adding that they were "constructive" on the pound, citing Britain's relatively fast COVID-19 vaccine programme.
The pound fell on Tuesday, losing 0.6% against the dollar and over 1% against the euro - its worst day against the single currency in five weeks as investors took cash off the table.
Against the euro, it traded 0.7% lower to the euro at 86.50 pence, having hit a five-week low of 86.62 pence.
Sterling's gains versus the euro this year have been largely due to Britain's faster vaccine rollout, relative to Europe, analysts say, meaning that the EU-UK vaccine row could affect euro-sterling.
Brussels and London sought to cool tension on Wednesday, declaring they were working "to create a win-win situation and expand vaccine supply for all our citizens".