A year ago it seemed like a utopia, but Spain recently reached 70% immunization for its population against COVID-19. The campaign began on Dec. 27, 2020, with doses of Pfizer and BioNTech, which were later supported by vaccines from AstraZeneca, Moderna and Johnson & Johnson.

The first to receive the vaccine were the elderly who lived in nursing homes, but today, everyone over 12 years of age is eligible for vaccination.

The countries closest to Spain, such as Italy, France or Germany, have barely passed the 60% vaccinated barrier. The same is for countries that began their vaccination campaigns earlier, such as the United States, Israel and the United Kingdom. The reluctance of the population to be vaccinated has been the main cause of the slowdown in those countries, something that has not happened in Spain.

Still, the country has not achieved the long-awaited herd immunity. With 33.24 million of its 47 million citizens vaccinated, no demographically similar country has managed to vaccinate faster. Canada would be the second, with 67% of its population immunized.

The Spanish Society of Immunology recognized that 70% of vaccination is an "insufficient" and "illusory" figure, as well as herd immunity.

According to experts, several variables are determining factors: the virus has multiple variants, the duration of immunity is also variable, and vaccines do not prevent people from becoming infected and contagious. It is difficult to achieve that immunity if they only protect against the risk of death and severity of the disease.

But not all is lost. To reach a place where the population's immunity is sufficient to avoid new waves of infection, more people need to be vaccinated. It is there that Spain has an advantage.

The population trusts and respects the work of its health system, regardless of political ups and downs. Older people still remember previous epidemics, such as polio, which wreaked havoc in the country and disappeared thanks to vaccination.

The new variants, such as the Delta or the South African, are more contagious and although vaccines protect against them, they are not as effective. After the drama experienced in Spain, with thousands of deaths in and out of nursing homes, there is also a solidarity component in vaccination. Whoever receives the injection protects himself from the virus, but also his environment.

What does seem like a fact is that the virus will not disappear. Since vaccines do not sterilize, people will continue to be infected. The number of deaths drops considerably if the data from the first wave are compared with the fifth in Spain: 45,000 between March and May 2020 and just 2,000 this summer.