Vaccines have proven to be one of the most life-saving public health interventions. With them, nothing less than 154 million child deaths have been prevented in the last 50 years; an achievement made possible by the progressive increase in vaccination coverage against pathogens such as polio, diphtheria, tetanus, measles, tuberculosis, and pertussis.
Compared to 1980, vaccination rates have doubled against the mentioned microorganisms, and the number of babies without any vaccines has been reduced by three-quarters.
But these advancements also conceal a trend that darkens the achievements and threatens their continuity. Since 2010, vaccination rates have stagnated or even decreased in many countries, as shown in a report on the global status of these immunizations that has analyzed data from 204 nations and is published this Wednesday in the scientific journal The Lancet.
If the trend is not reversed, the authors of the study warn that the vaccination goals set for 2030 may not be achieved.
"Despite the monumental efforts made in the last 50 years, progress is far from universal. Very high numbers of children remain unvaccinated," stated Jonathan Mosser from the University of Washington in a press release. He also highlighted that "persistent global inequalities, the challenges of the Covid pandemic, and the growth in misinformation and vaccine hesitancy have contributed to the faltering progress in immunization."
The study highlights some striking examples of this concerning trend. It shows that between 2010 and 2019, measles vaccination decreased in 100 out of the 204 countries studied. It also reflects that in 21 out of the 36 countries considered high-income, decreases in vaccination rates for at least one dose in coverage against diphtheria, tetanus, pertussis, measles, polio, or tuberculosis were experienced.
The data from Spain presented in the study show a decrease in vaccination coverage between 2019 and 2023. The vaccination rates recorded in 2019 were 98%, a percentage that dropped to 96.7% five years later. The number of children without any doses of basic vaccines, such as the combined immunization against diphtheria, tetanus, and pertussis (also known as DTaP), increased from 7,390 to 10,734 during that period, according to the study's figures.
Jaime Pérez, president of the Spanish Association of Vaccinology, points out that in Spain, "in the pediatric population, we have high vaccination coverage rates that are being maintained. It is true that we have coverage rates that do not reach vaccination goals (such as, for example, measles), but many times this data is due more to registration issues than actual lack of vaccination," stated the specialist, who also noted that in recent years, "an increase in the population rejecting vaccines is observed, something that did not happen before Covid-19. Therefore, it is necessary to improve communication of results and continue to emphasize the importance of vaccination," he added.
The Covid pandemic has had an impact on the challenges that vaccination has been facing since the early years of the century, as highlighted in the study, estimating that globally, 15.6 million children missed out on the three doses of the combined vaccine against diphtheria, tetanus, and pertussis or the measles vaccine between 2020 and 2023; 15.9 million did not receive polio immunization, and 9.18 million missed out on tuberculosis vaccination.
In 2023, half of the 15.7 million children without even the most basic vaccines lived in just eight countries, most of them located in sub-Saharan Africa. These countries are Nigeria, India, the Democratic Republic of the Congo, Ethiopia, Somalia, Sudan, Indonesia, and Brazil.
The study indicates that to achieve the goal set for 2030 of halving the number of children without even the most basic vaccines compared to 2019 data, efforts need to be doubled.
However, estimates predict that only the vaccination against diphtheria, tetanus, and pertussis has a chance of achieving a global coverage of 90%, and only if the most optimistic of the scenarios presented is met.
The study emphasizes the persistence of outbreaks of diseases that can be prevented with vaccination. It reflects the polio cases recorded in Pakistan, Afghanistan, or Papua New Guinea and shows concerning data on the measles situation in Europe and other parts of the world.
In 2024, these infections multiplied by 10 in the European Union and the European Economic Area. Likewise, outbreaks in the US have already exceeded 1,000 confirmed cases in 30 states, figures that are higher than those for the entire 2024.
In Spain, there have also been outbreaks and sporadic infections in recent months. Specifically, in 2024, 217 cases were confirmed, according to data from the Vaccine Advisory Committee of the Spanish Pediatric Association, which highlights that the figure is "much higher than in the 2021-2023 triennium." In the first quarter of 2025, 179 confirmed cases were detected (57 imported, 69 related, and 53 more of unknown origin or under investigation), with Andalusia, the Basque Country, Catalonia, and Melilla being the most affected regions.
Despite the increase in cases, Pérez sends a message of reassurance and points out that "a return of measles to significant figures would not be expected in our country."
However, he clarifies that to eliminate the disease, it is necessary to have very high vaccination coverage against the disease. In that sense, he warns that if those figures are not achieved, "we could indeed have a problem in the elimination goals and have more and more outbreaks, with the implications that can have for the affected individuals. Let's remember that, on average, 20% present a complication, especially pneumonia. Unfortunately, it is a disease that can lead to death in 1-3 out of every 1,000 cases," he reminds.
The authors of the report call for measures to address the inequalities and the various challenges posed by vaccination on a global scale, a demand that Pérez agrees with.
"As the report rightly indicates, in certain vaccines, we have taken steps back, and this would have to be added to the lack of collaboration from the US in international public health, so the situation may be even more concerning in the future," he laments.
Among the most pressing challenges, the expert mentions the need to "maintain vaccination coverage in childhood, improve adult vaccination rates, introduce new vaccines at an appropriate speed, and build loyalty among the population through the health outcomes that vaccines provide."
Regarding the latter point, Pérez recalls that immunization with the monoclonal antibody against RSV -respiratory syncytial virus- led to a reduction of 10,000 hospitalizations in Spain. "That is the type of message we need to convey to our population," he concludes. "That vaccines are safe and effective."
The Spanish Association of Vaccinology against the dismissal of 17 experts in the US
The Spanish Association of Vaccinology expressed its rejection on Tuesday to the dismissal of the 17 members of the Advisory Committee on Immunization Practices of the United States (ACIP) carried out by the US Secretary of Health, Robert F. Kennedy Jr.
The replacement of the committee members, who have proven prestige, has been done, as the vaccinologists denounce, "quickly and irregularly," and furthermore, the new appointments have opted for "profiles - with the exception of one of them - that either have no experience in the field of immunizations or have shown a negative view of them". For this reason, they emphasize, "it is quite difficult to expect an objective and expert view on immunizations."
The Spanish organization has joined the protest of more than 20 American scientific societies, including the American Academy of Pediatrics and the American Academy of Family Physicians, and has stressed that "vaccines are for everyone, for Democrats and Republicans, for voters of any political party. Politics should not interfere in any case with science, either against it or appropriating it."