Thierry Breton, European Commissioner for Internal Market, visited the Belgian plant under scrutiny after AstraZeneca announced delivery delays for its COVID-19 vaccine.
The site at Seneffe, south of Brussels, manufactures the active ingredient of the vaccine.
Breton has been recently put in charge of a new task force whose mission is to identify and eliminate bottlenecks in vaccine production sites and adjust output to new variants.
Following weeks of intense criticism over setbacks and shortages, Breton said he wanted to start a "listening tour" to fully understand the complexity of vaccine production and supply chains.
Speaking to Euronews at the end of his visit, he took a moment to reflect on the magnitude of the challenge that Europe is currently facing.
"Never in European history and, I think I can say that, in the history of mankind, has an industrial vaccine production started so fast. Therefore it is perfectly normal that we could be seeing, here and there, some problems," Breton said.
"When you start a production of such magnitude, it's quality first, which could slow down the production. But I am really very confident, after what I have seen here today, that we will be able to meet our objectives."
Echoing the words of President von der Leyen earlier on Wednesday in the European Parliament, Breton expressed his concern regarding the new coronavirus variants and their potential disruptive effect on supply chains.
"How do we in, let's say, 18 months, manage to become totally independent in vaccine matters? How can we follow the evolution of the variants, how can we get organised, is this what we will do first? How can we start thinking about testing whether the vaccines are also efficient against the new variants?" Breton said.
Cédric Volanti, general manager of EU services at Thermo Fisher Scientific, which runs the plant, said it is fulfilling all its contractual obligations with AstraZeneca.
Coincidentally, while Breton was touring the site, AstraZeneca announced cooperation with German vaccine manufacturer IDT Biologika. The two companies are exploring options to accelerate the output of COVID-19 vaccines in the second quarter to support Europe's immediate vaccination needs during the pandemic.
AstraZeneca has been at the centre of the storm over the EU's vaccine roll-out. When news broke last month that the Anglo-Swedish pharmaceutical giant was going to cut deliveries by 60% in the first quarter of 2021, suspicion arose that the company was actually redirecting doses produced in the EU towards the United Kingdom.
AstraZeneca signed a deal with the UK several months before it agreed to supply the EU with 300 million doses of its vaccines, with an option for a further 100 million doses.
The public row between the company and the European Commission led to the publication of the full - but heavily redacted - EU contract and to the introduction of an exports control mechanism to increase transparency over vaccines produced within the bloc.
The first EU shipments of the AstraZeneca vaccine arrived in early February, with 17 million doses expected over the next weeks. Despite the approval by the European Medicines Agency, several EU countries have ruled out using the jab for the elderly.
On Monday, South Africa temporarily suspended its COVID-19 vaccination programme after a study found that the AstraZeneca vaccine may not be effective against the new variant of the virus that has spread across the country.