MADRID - Spanish Prime Minister Pedro Sanchez tested positive for COVID-19 on Sunday morning.

Sanchez confirmed the news in a Twitter post, saying "this morning, I have tested positive for COVID-19," adding although he would not be able to assist a planned Socialist Party event close to Barcelona, he would "continue working, taking maximum precautions."

The news came just 24 hours before Spain begins its campaign to give a fourth dose of vaccine to people aged over 60, health workers and people living in residential care homes.

This second "booster dose" will use vaccines modified to offer protection against the latest strains of COVID-19, after the health ministry reported a slight rise in the 14-day incidence of the virus in the over-60's in over two months.

The incidence rose from 129 cases per 100,000 inhabitants to 136 cases per 100,000 in the data provided by the ministry on Friday, although the number of intensive care beds occupied by COVID-19 patients has dropped to just 129, around 1.5 percent of the intensive care beds in Spain.