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A drop in childhood vaccination

The pandemic has exacerbated a decline in immunization rates, which fell by 65% in some states in 2020

Some of the 29 vaccines available for free in the Brazilian public health system

Léo Ramos Chaves

Urgent action is needed to increase and sustain childhood immunization at a high level in Brazil. After remaining stable at levels considered high for nearly two decades, vaccination coverage peaked in 2015, then began to decline. In some areas, the initial drop was followed by a slight recovery, before falling further. Since 2020, immunization rates already considered low have plummeted, influenced by the pandemic. Recent studies suggest that for some vaccines, uptake in some Brazilian states fell by 65% in 2020. Globally, there was a 30% decrease in the early months of 2020.

Restricting people’s movement to reduce circulation of the novel coronavirus and reallocating health teams to care for COVID-19 patients both contributed to the realization of a situation feared by pediatricians and epidemiologists in Brazil. Of the 15 vaccines offered to children aged four and under and for which information is publicly available, at least nine failed to achieve the coverage targets set by health authorities. These vaccines protect against at least 17 serious infectious diseases, some of them highly communicable, such as measles and whooping cough, or debilitating, such as meningitis and polio, which paralyzes children and can be fatal.

Alexandre Affonso

In Brazil, the vaccination of both children and adults is coordinated by the National Immunization Program (PNI). Data from the PNI’s online information system (SI-PNI/DataSUS), accessed by Pesquisa FAPESP on February 10, show that in 2021, even the most successful of these nine vaccines were only given to 71% of the target population. Just two of them—the triple viral vaccine against measles, mumps, and rubella (MMR) and the pneumococcal vaccine, which helps prevent pneumonia, meningitis, and otitis—achieved this rate, which is already below the level recommended by the PNI. The rest had even lower levels of coverage, including the BCG, which protects against tuberculosis and is given in maternity wards (see graph above).

“These numbers indicate that at least 900,000 children in Brazil were not vaccinated in 2021. We’re getting close to the rates we had in the 1980s,” says Carla Domingues, a sociologist who directed the PNI from June 2011 to July 2019.

Office for Social Communication, Health Department, Brazilian Ministry of Health | Brazilian Ministry of Health In 1986, Darlan Rosa, a graphic artist from Minas Gerais, created the character Zé Gotinha to reduce children’s fear of vaccination during the polio eradication campaign, and it was later adopted as the PNI’s mascotOffice for Social Communication, Health Department, Brazilian Ministry of Health | Brazilian Ministry of Health

Created in 1973, the program was one of the first health policies aimed at universal immunization in the country. For a long time, it was seen as an example of success worldwide. In 1977, the PNI began routine administration of the BCG vaccine, in addition to vaccines for measles, polio, and DTP, which protects against diphtheria, tetanus, and whooping cough (pertussis). Routine vaccination, together with mass immunization campaigns and barrier vaccinations to contain outbreaks, eliminated rubella and the polio virus in the country, the latter of which caused some 10,000 cases of the disease a year in the 1980s. Measles, diphtheria, and whooping cough were all close to being stamped out. The program was gradually expanded, now offering 29 vaccines free of charge to children and adults. After reaching almost universal coverage between 2010 and 2015, something changed and childhood vaccination rates began to fall. There was a slight recovery in 2018, but the downward trend was resumed the following year and worsened alongside the pandemic.

“When the decline became evident in 2017, the Ministry of Health acted in partnership with state and municipal health departments and scientific societies to promote a national response. The numbers rose again, but then they plummeted,” recalls Domingues, who was in charge of the PNI at the time. “Maintaining high vaccination rates among the population is a job that requires continuity,” she explains. Public health experts say that this continuity can only be achieved in a well-structured health system.

Alexandre Affonso

Current rates for at least nine vaccines given to children—BCG, hepatitis A, hepatitis B, meningococcal C, pentavalent, pneumococcal, polio, rotavirus, and MMR—were 23 to 39 percentage points lower in 2021 than in 2015 (see graph above). “Although the data is not 100% accurate, this situation could lead to the resurgence of diseases that have previously been eliminated or controlled,” says Renato Kfouri, president of the Immunization Department at the Brazilian Society of Pediatrics (SBP) and director of the Brazilian Society of Immunization (SBIM) and a private vaccination clinic. “One of the diseases that usually appears first is measles, which is caused by an easily transmitted virus that is still uncontrolled in many countries. There is also a risk that cases of diphtheria and pertussis will increase and that polio will reappear.”

Although municipal authorities have until March to submit their data to the PNI, the 2021 numbers are highly unlikely to reach the recommended levels. The World Health Organization (WHO) recommends that the BCG and rotavirus vaccines, the latter of which reduces the risk of severe diarrhea, be given to at least 90% of children. The recommended coverage for the others is 95%. This is the only way to achieve herd immunity and protect both vaccinated children and those not immunized against these diseases.

Fernando Frazão / Agência Brasil Child being vaccinated against polio during an immunization campaign in Rio de Janeiro in 2018Fernando Frazão / Agência Brasil

Pesquisa FAPESP asked the Ministry of Health for its opinion on the causes of the decline and the severity of the situation, as well as an overview of what actions have been taken to reverse the trend. The ministry replied that “it has been assessing falling vaccine coverage through studies of vaccine coverage surveys and rapid monitoring.” It also says that other initiatives have been adopted, such as the strengthening of joint actions with the primary health care services, which are responsible for vaccinations and implementing national immunization campaigns, such as the “multivaccination campaign” that took place in October and November of 2021. The ministry stated that it is working on increasing the number of professionals qualified to work in vaccination and that it has signed a partnership with the Oswaldo Cruz Foundation (FIOCRUZ) to implement project Reconquista das Altas Coberturas Vacinais (“Restore high vaccine coverage”), the pilot for which will shortly begin testing tailored actions designed to raise the vaccination rate of children in 41 municipalities in the Brazilian states of Amapá and Paraíba.

The drop in vaccination coverage over the last two years can be partly attributed to the novel coronavirus pandemic. Recent studies comparing the numbers of children being vaccinated in the years before COVID-19 with the numbers recorded after the pandemic began suggest the impact is not negligible.

In an article published in the Journal of Medical Microbiology in August 2021, Marcelle Moura Silveira, a biochemist from Anhanguera College in Pelotas, Rio Grande do Sul, and her colleagues from the Federal University of Pelotas (UFPel) analyzed the change in uptake of four vaccines (BCG, meningococcal, pneumococcal, and DTP). The biggest drop occurred in 2020, when the pandemic first began. Between 2019 and 2020, application of the four vaccines dropped by between 10 and 23 percent.

Léo Ramos Chaves Child being vaccinated against measles during an immunization campaign in Rio de Janeiro in 2018Léo Ramos Chaves

And these were not the only ones for which uptake fell in the period. At the Federal University of Minas Gerais (UFMG), a group led by Tércia Moreira Ribeiro da Silva compared the coverage of another important childhood vaccine—the MMR—during two periods: from April 2019 to March 2020, before social-distancing measures were introduced in Brazil, and from April to September 2020, when people started staying at home and city streets were quieter. According to the results, published in the journal BMC Infectious Diseases in December 2021, the number of vaccine doses administered monthly fell by an average of 43%, from 1.6 million in the first period to 935,000 in the second.

The drop was uneven across the country and most profound—and statistically significant, ranging from 48% to 65%—in seven states: three in the North (Acre, Amazonas, and Roraima), two in the Northeast (Paraíba and Sergipe), one in the Southeast (Rio de Janeiro), and one in the South (Santa Catarina). After analyzing the distribution of municipalities with low coverage, the researchers found that in the North and parts of the Northeast, they are often located very close together, forming pockets of people vulnerable to infection by measles, mumps, and rubella. “There is a greater likelihood that these viruses, especially measles, will circulate again in these areas,” says Tércia Ribeiro da Silva.

The pandemic is one of the factors behind the decline, but it is unlikely to be the only contributor. In a study published in Revista Mineira de Enfermagem in 2020, the UFMG team observed that the MMR vaccine was slightly less available in the municipalities in the North than in the other four regions. Ed Wilson Vieira, Tércia Ribeiro da Silva, and their colleagues examined the situation at 19,752 vaccination centers across Brazil based on records taken by the Primary Healthcare Quality Improvement Program in 2013 and 2014 (a program terminated by the current administration) and found that the probability of a vaccine being available was lower at the locations with the worst infrastructure. This includes centers that had no vaccination room or shared one with other activities, and some that did not even have an exclusive refrigerator or cooler to store the vaccines.

Fernando Frazão / Agência Brasil Child being vaccinated against COVID-19 in São PauloFernando Frazão / Agência Brasil

Perhaps it is no coincidence that the reemergence of the measles virus in Brazil in 2018 started in the North. After recording just a few cases in 2015, Brazil was certified free of the infectious agent the following year by the Pan American Health Organization (PAHO). With the drop in vaccination rates, however, the measles virus begun circulating once again. There were 10,400 cases recorded in 2018; 21,000 in 2019; and 8,400 in 2020, resulting in tens of deaths.

As one of the countries most affected by the COVID-19 pandemic, with 27.5 million people infected with the novel coronavirus and almost 640,000 deaths recorded by mid-February of this year, Brazil was not the only nation to show a significant reduction in immunization against other diseases. A group led by pediatrician Anita Shet from Johns Hopkins University, USA, gathered information on the number of doses of the DTP and measles vaccines administered in 170 countries in 2019 and 2020. Published in The Lancet GlobalHealth in February, the study identified a drop of approximately 30% in global vaccination rates, primarily in the first half of 2020. It included data from 27 countries and three territories in the Americas. In 16 of them (53%), there was at least a partial interruption in vaccination due to reduced demand, difficulties obtaining vaccines, staff shortages, and other factors. According to estimates by the WHO and the United Nations International Children’s Emergency Fund (UNICEF), an additional 4 million children were not vaccinated in 2020, bringing the total number of nonimmunized children in the year to 23 million.

Refined over more than two centuries, vaccines have become one of humankind’s most effective life-saving strategies. Data from the WHO, for example, show that the use of vaccines reduced the worldwide number of measles cases from 854,000 in 2000 to around 150,000 in 2020 and the number of mumps cases from 544,000 to 270,000 in the same period. They also suggest that vaccines prevent the death of 4 to 5 million children each year. According to the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, USA, the widespread use of vaccines in recent decades has reduced the number of deaths of children aged under 5 from diseases totally or partially preventable by vaccination from 5.5 million in 1990 to 1.8 million in 2017.

Alexandre Affonso

The global increase in vaccination coverage over the last four decades is undeniable. In a recent study led by Stephen Lim and Jonathan Mosser of the IHME, an international group of researchers looked at the routine use of 11 vaccines in 204 countries between 1980 and 2019. Published in The Lancet in August last year, the study revealed the existence of a universal pattern. The proportion of people immunized—particularly with the measles, polio and diphtheria, tetanus, and whooping cough vaccines—has grown worldwide, from about 40% of the global population in the 1980s to around 80% at the end of the last decade. In that time span, the total number of unvaccinated children dropped from 56.8 million to 14.5 million. Vaccination coverage increased rapidly in the 1980s and slowed slightly in the 90s and 2000s: in 2010, almost 120 countries managed to administer the three vaccines to 90% of children. From that year onward, however, the decline set in: vaccination rates fell in 94 countries, including Brazil, one of the few in which there were children who did not receive any of the main vaccines in 2019.

In 2018, when the most consistent signs of a drop in childhood immunization emerged in the country, a report by Pesquisa FAPESP interviewed pediatricians, immunologists, epidemiologists, and health authorities in search of an explanation. At the time, experts listed at least nine reasons for the phenomenon (see Pesquisa FAPESP issue nº 270), ranging from a misconception that some of the diseases preventable by vaccines no longer exist to a lack of knowledge of the vaccine schedule, which has become more complex and requires multiple visits to the health center before children reach the age of 15 months (see the online version of the report). Other potential reasons included a fear of potential adverse reactions, a fear that a high number of vaccines could overwhelm a child’s body, and parents not having enough time to take their children to health centers, which are usually only open during business hours. A change to the country’s system for recording vaccination data also had an impact. In 2012, all 36,000 vaccination posts nationwide switched to a new, more laborious system that requires staff to record the patient’s name and other personal data. Other factors that cannot be ruled out include the effects of fake news on the topic and the organized efforts of antivaccination groups, which although incipient in Brazil, are more active in Europe and North America—the recent protests by truck drivers against Canada’s COVID-19 vaccination passport, for example.

“All these reasons exist and remain valid. The impact of some seems to have been reinforced in recent years as the antivaccination movement has grown, fake news on social media has intensified, and Brazilian public figures have spoken openly against vaccines,” says Fernando Barros, a pediatrician, epidemiologist, and professor at UFPel and the Catholic University of Pelotas (UCPel) who studies childhood vaccination rates. “Everyone used to speak very carefully and responsibly about vaccines. Like any drug, they can cause adverse events, but these are extremely rare,” says Eliseu Waldman, an epidemiologist from the School of Public Health (FSP) at the University of São Paulo (USP).

Dave Chan / AFP via Getty Images Protests against mandatory COVID-19 vaccination passports in Toronto, Canada, in early FebruaryDave Chan / AFP via Getty Images

In addition to these factors, aggravated by the pandemic’s impact on health services, there are others, such as infrastructure problems and the need to improve the training of vaccination center staff. When planning the Reconquista das Altas Coberturas Vacinais project with the Ministry of Health in December, Akira Homma, a virologist and senior scientific advisor at FIOCRUZ’s Institute for Technology in Immunobiologicals (Bio-Manguinhos), visited 15 municipalities in Paraíba and Amapá and talked to mayors, secretaries, and the staff responsible for giving vaccines. He found that the conditions at vaccination posts were highly heterogeneous. Some were very clean and well equipped, while others had infrastructure problems, such as no adequate refrigerator to store vaccines. He observed that the staff administering vaccines, who earned low wages and sometimes had to supplement their income with second jobs, were almost always unmotivated. “We need to value the work of those on the front lines and encourage them to be more active in the search for people who are not fully vaccinated, in addition to making society see immunization as one of the most important ways of ensuring the good health of the population,” says Homma.

Another problem is the lack of coordination in the Brazilian public health system (SUS) and within the PNI, marked by a worsening of indicators related to various diseases and infant mortality. Since mid-2019, the program’s director has been replaced four times. Pesquisa FAPESP requested an interview with Samara Furtado Carneiro, who took over leadership of the PNI in January, but was turned down by the ministry’s press office. “States and municipalities work well, but national coordination is needed,” says Barros, from UFPel.

The list of potential causes for the continuing fall in vaccination coverage in the country, written in 2018, offers various plausible explanations, but they vary from one region to another. To what extent each of them contributes to the phenomenon is still unknown. With a new national survey nearing completion, Carla Domingues and José Cassio de Moraes, an epidemiologist from the Santa Casa de São Paulo School of Medical Sciences, are intending to answer some of these questions and better understand why some Brazilians have stopped vaccinating their children in recent years. With funding from the Ministry of Health and the Brazilian National Council for Scientific and Technological Development (CNPq), a group of researchers is interviewing 40,000 parents and guardians of children in 27 state capitals and other cities with more than 200,000 inhabitants, and taking photographs of vaccination cards. “We want to know what proportion of children are fully vaccinated, which parents have most difficulty taking their children to health centers, how many are missing vaccines, and other information,” says Moraes.

Aspects of the problem still unknown

To reverse the decline in childhood immunization, we first need to know the true scale of the problem and identify its real causes. Experts say that to do this, the issue needs to be investigated via two distinct and complementary strategies: quantitative and qualitative studies.

The former involves taking measurements to quantify a given attribute—the number of unvaccinated children in a city, for example—and then using statistical methods to search for relationships with other attributes. The approach is used to identify patterns and trends associated with a phenomenon. It can help give a rough idea of the size of the problem.

Qualitative studies, meanwhile, involve gathering information through interviews and observations, helping shed light on the reasons behind the patterns and trends. “In our research, we epidemiologists often find associations between two factors and present plausible hypotheses to explain them, but it is qualitative studies, which identify the reasons given by people themselves, that allow us to confirm or refute these explanations,” says Fernando Barros, from UFPel.

The experts interviewed for this report raised many questions that are yet to be answered using one investigative strategy or another, such as: what proportion of children are fully immunized in Brazil? Is vaccine coverage homogeneous? Are there pockets of unvaccinated people? If so, where are they? Are vaccines available at health centers in regions with low immunization rates? What is the structure of these health centers like? What are the most efficient strategies for informing the population about the importance of immunization? Are vaccination posts difficult to access? Do parents know how many and which vaccines their children should have? Do they consider it important to vaccinate their children? Do they trust vaccine safety and efficacy? Are they antivaccine? For what reasons have they not had their children vaccinated? How effective is the dissemination of vaccination campaigns via traditional media and social media? In addition to many others.

“We need to know the response to many of these questions to be able to identify strategies for efficiently restoring confidence in vaccines and the importance of taking them,” says Eliseu Waldman, from USP.

Scientific articles
SILVEIRA, M. M. et alEffect of COVID-19 on vaccination coverage in BrazilJournal of Medical Microbiology. Nov. 30, 2021.
DA SILVA, T. M. R. et al. Number of doses of Measles-Mumps-Rubella vaccine applied in Brazil before and during the COVID-19 pandemicBMC Infectious Diseases. Dec. 9, 2021.
VEIRA, E. W. et al. Estrutura e localização dos serviços de vacinação influenciam a disponibilidade da tríplice viral no BrasilRevista Mineira de Enfermagem. Feb. 2020.
SHET, A. et al. Impact of the SARS-CoV-2 pandemic on routine immunisation services: evidence of disruption and recovery from 170 countries and territoriesThe Lancet Global Health. Feb. 10, 2022.
GBD 2020, RELEASE 1, VACCINE COVERAGE COLLABORATORS. Measuring routine childhood vaccination coverage in 204 countries and territories, 1980–2019: a systematic analysis for the Global Burden of Disease Study 2020, Release 1The Lancet. Aug. 7, 2021.