The head of healthcare management in Italy's largest region, Lombardy, said on Wednesday there was a growing reluctance amongst residents to accept AstraZeneca's Covid-19 vaccine because of safety fears.
Public confidence in the vaccine has been battered worldwide since reports emerged linking it to very rare but potentially fatal blood clots in the brain.
"It is a phenomenon that in recent days is becoming more serious than we might have thought," Giovanni Pavesi told the regional health commission in Lombardy, which is centred on Italy's financial capital Milan.
Officials elsewhere across the country reported similar problems, posing a major headache to the government as it struggles to ramp up vaccination efforts.
"The rejection of AstraZeneca has been seen in numerous regions," said Antonino Spirlì, acting president of Calabria, the toe of Italy's boot, where the region's main hospital reported up to 70% of people were turning down AstraZeneca.
"It seems that many people need more time to decide what to do," Spirli told a group of foreign reporters.
Italy, like many European countries, briefly halted AstraZeneca inoculations last month over the concerns, but resumed them for those aged 60 and over after EU regulators said the benefits of using the vaccine outweighed the risks.
This recommendation went against initial advice that said the shot was only effective for those aged under 55. "Too often governments have struggled to confirm what was said a couple of days beforehand," said Calabria's Spirli.
Underscoring the confusion within Europe, Denmark announced on Wednesday that it would no longer use AstraZeneca, while the French government spokesman voiced his confidence in the product.
AstraZeneca was not immediately available for comment on Wednesday. It has said in the past it is working to understand individual cases of side-effects and "possible mechanisms that could explain these extremely rare events".
Italy has looked to restore trust, with Prime Minister Mario Draghi himself getting vaccinated with AstraZeneca last month. But in many people's minds, the damage had already been done.
Nello Musumeci, the president of the region of Sicily, has said up to 80% of people on the Mediterranean island were refusing AstraZeneca. In Italy's heel, Puglia, the rejection rate was put at 40%.
"It is natural that the alarm is so high, but we have a duty to believe scientists who say it is more dangerous not to vaccinate than vaccinate," Musumeci said at the weekend.
More than 115,000 people have died of Covid-19 in Italy, the second highest tally in Europe after Britain, with the country still registering hundreds of deaths each day.
It is pinning its hopes on mass vaccinations to put an end to the 14-month-old crisis, but slower-than-expected arrivals of doses coupled with growing public scepticism and a bungling bureaucracy have significantly complicated matters.
Fears that another vaccine might also trigger rare bloodclots sowed further confusion this week.
Italy delayed on Wednesday deliveries of some 184,000 shots of the vaccine made by US drugmaker Johnson & Johnson after US authorities put it on pause to review the situation.
J&J has said it is working closely with regulators and noted no clear causal relationship had been established between the events and its shot.
The first shipment of the J&J shots only arrived on Tuesday and had been expected to be rushed into vaccine centres.
"Here we are in the hands of God: if it goes right it goes right, if it goes wrong it goes wrong. I don't know, I don't know what to say," said Rome resident Annamaria Gingaroli.