According to El Mundo and El Confidencial, Princess Elena, 57, and Princess Cristina, 55, got the inoculations in February while visiting their father, ex-king Juan Carlos, in Abu Dhabi.
The two royals would not yet qualify for the jab under Spain’s Covid-19 immunisation programme, which gives priority to older people and the most vulnerable.
Juan Carlos, who abdicated in 2014, moved to the United Arab Emirates (UAE) in August amid growing questions over his financial dealings.
A spokesman for the royal palace refused to comment on the reports on the grounds that the princesses are formally “not part” of the institution and the palace has no say in their activities.
Podemos, the junior partner in Socialist Prime Minister Pedro Sanchez’s minority coalition government which is staunchly anti-monarchy, strongly criticised the royals.
“The vaccination of the princesses is more news which contributes to discrediting the monarchy. For the public, this constitutes preferential treatment and privileges,” Equality Minister Irene Montero, a member of Podemos, told public television TVE.
The monarchy is one of several issues which dividing Podemos and the Socialists, which have governed since January 2020.
It is the first time that an anti-monarchy party has been in power since Spain returned to democracy in the 1970s.
The controversy over the vaccinations comes less than a week after Juan Carlos settled a debt of nearly 4.4 million euros ($5.3 million) with the
Spanish tax authorities in a bid to avoid a potential lawsuit. The back-taxes were due on the previously undeclared value of private jet flights — worth eight million euros, according to press reports — paid by a foundation based in Liechtenstein belonging to a distant cousin of Juan Carlos.
The payment caused outrage in Spain, with Sanchez saying he shared the “rejection” which the “majority” of Spaniards feel towards what he called Juan Carlos’ “uncivic behaviour”.
The country’s former intelligence chief, Felix Sanz Roldan, also received the coronavirus vaccine in Abu Dhabi duri
ng a visit to Juan Carlos, according to Spanish media reports.
Spain’s chief of defence staff resigned in January after it was revealed that he got the coronavirus jab in Spain despite not being on a priority list.