Costa mentioned in a press release he'll self-isolate for seven days, in accordance with the nation's pandemic guidelines.
Costa, who has been Portugal's prime minister since 2015 and is about to serve one other 4 years, was attributable to meet with President Marcelo Rebelo de Sousa on Wednesday as a primary step towards being sworn in.
It wasn't instantly clear if one other Socialist Get together official would change him.
The Socialists took no less than 117 seats in Portugal's 230-seat parliament, with 4 seats nonetheless to be allotted, in what was a thumping victory.
Costa, together with scores of Socialist officers and supporters, celebrated the rout in a windowless basement room in a Lisbon resort, with hugging and yelling.
Media representatives had been additionally current for Costa's victory speech within the packed and low-ceilinged room, which drew criticism as a poor selection of venue for celebrations.
Folks had been required to indicate digital vaccine certificates and put on masks on the occasion, however checks weren't all the time carried out and a few individuals pulled their masks all the way down to their chin.
The election occurred amid a surge in COVID-19 circumstances blamed on the Omicron variant.
Round 1 million individuals had been in house confinement on election days however they had been allowed to exit to vote.