Almost 70 medics who attended a large Christmas party in southern Spain have since tested positive for Covid-19, authorities say.
Most of the 68 infected are doctors and nurses working in the intensive care unit at Málaga’s regional hospital.
Health authorities said they were all at a party attended by about 170 people last Wednesday.
All guests returned negative antigen tests before the event but more than half are now isolating.
The infected staff were all fully vaccinated and are showing no symptoms, health authorities said.
Local reports say doctors and nurses from other departments at Málaga’s regional hospital in Andalusia have been redeployed to cover for their colleagues.
The outbreak has heightened concerns about the risk of spreading Covid at social events during the Christmas period.
To mitigate this risk, health authorities in Andalusia had advised hospital staff not to attend Christmas parties.
On Monday, Spanish Prime Minister Pedro Sánchez urged people to remain wary of Covid over the holidays.
“We must not lower our guard,” he told reporters in the capital, Madrid.
Like many European countries, Spain has recorded an increase in Covid infections in recent weeks, raising fears of a deadly fourth wave of cases as the colder winter months approach.
There is also concern around Europe about the spread of the Omicron variant, which experts fear may be more transmissible and evade some immunity to Covid.
Spain has only officially reported several cases so far, including four in the Balearic Islands.
In total, Spain has recorded about 5.1 million coronavirus infections and 88,000 deaths since the start of the pandemic.
Spain was hit hard by the pandemic in 2020, but the situation has since stabilised, largely thanks to the country’s relatively high vaccination rate. About 74% of the total population have been fully vaccinated and 9% have had booster shots, according to the latest data.
Last week, Spain’s health minister, Carolina Darias, ruled out making vaccination against Covid mandatory in the country.
“I understand why countries with a low vaccine coverage are planning it,” Ms Darias said. “But in Spain, we are one of the leading countries for vaccination in Europe and the world.”
She said other tools being used in Spain, including “masks being mandatory inside and outside when safe distance cannot be maintained”.