According to the Spanish Epidemiological Society (SEE), 19 percent of the population is immune to coronavirus, a total of 9.7 million people.
The measure is based on a combination of those who have either been vaccinated or have had the illness already and have acquired antibodies to fight the virus.
An estimated 4.7 million people had antibodies from the virus in the most recent study by the research body Carlos III Health Institute.
A further two million people have become immune since autumn and three million people have received the vaccine.
Joan Caylà, a spokesperson for the SEE, told Spanish medical publication Redacción Médica that this figure should ideally reach 70 percent of the population before summer.
This would allow cases of coronavirus to fall, the tourism industry to reopen and the Spanish economy to recover.
Caylà said that those who have had the virus should wait six months until after they are diagnosed before they can receive a vaccination. Those who have not had the virus should be prioritised in the vaccination rollout.
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“It makes sense to vaccinate those who have not had Covid first so that the short term results from vaccination will be faster,” Caylà said.
“We know that those who have had the virus, with clinical proof, have immunity for a certain time and so they are not a priority.”
The increase in herd immunity comes after there were more Spanish coronavirus deaths in February than any month since April.
More than 10,000 people died from the virus during February, 15 percent of the total number of deaths during the pandemic.
The largest portion of deaths took place in Madrid, Andalusia, Catalonia, Valencia, Castilla y Leon and Castilla-La Mancha.
However, cases of coronavirus fell throughout the month, from 865 cases per 100,000 residents at the beginning of the month to less than 200 cases per 100,000 residents in the fourteen days to February 26th.
By Ian Johnston