The younger the child, the harder their body struggles to respond
No Brasil, doenças que pareciam vencidas voltam a circular entre os mais vulneráveis: bebês com menos de seis meses, cujos sistemas imunológicos ainda não estão prontos para enfrentar o mundo. Em 2024, quase 7.800 casos de coqueluche foram registrados no país — um salto que reflete não uma falha da ciência, mas uma falha coletiva de adesão. A chamada 'estratégia casulo', que propõe vacinar todos os adultos ao redor de um recém-nascido, oferece uma resposta ao mesmo tempo simples e profunda: proteger o frágil por meio da imunidade do forte.
- O Brasil registrou 7.800 casos de coqueluche em 2024 — um aumento de mais de 7.500 casos em relação ao ano anterior, sinalizando uma crise de saúde pública em aceleração.
- Bebês com menos de seis meses não têm defesas biológicas suficientes contra coqueluche, sarampo, influenza e difteria, tornando-os dependentes da imunidade de quem os cerca.
- A queda na cobertura vacinal iniciada durante a pandemia de COVID-19 nunca se recuperou completamente, alimentando surtos cíclicos que especialistas dizem ser previsíveis e evitáveis.
- A 'estratégia casulo' propõe vacinar pais, avós e cuidadores como escudo indireto ao recém-nascido, aproveitando vacinas já disponíveis gratuitamente no sistema público.
- O custo das vacinas — cerca de 200 reais por dose em clínicas privadas — e a falta de percepção de risco entre adultos são os principais obstáculos à adesão.
- Especialistas alertam: sem mudança nos hábitos de vacinação dos adultos, os surtos continuarão se repetindo a cada três a cinco anos, com os bebês pagando o preço mais alto.
O Brasil assiste ao retorno de doenças que acreditava ter deixado para trás. Em 2024, quase 7.800 pessoas contraíram coqueluche — um salto alarmante em relação ao ano anterior, quando o país já enfrentava um surto. Para especialistas, a causa é clara: adultos que convivem com recém-nascidos simplesmente não estão vacinados.
Bebês com menos de seis meses são os mais vulneráveis. Seus sistemas imunológicos ainda estão em formação, e sua anatomia respiratória não tem maturidade para combater infecções graves. A pediatra Jorgete Maria e Silva, do Hospital das Clínicas da USP de Ribeirão Preto, explica que quanto menor a criança, maior a dificuldade do organismo de responder a doenças — tanto pela ausência de imunidade prévia quanto pelas limitações físicas do próprio corpo.
A resposta proposta pelos especialistas é a 'estratégia casulo': vacinar todos os adultos próximos ao recém-nascido — pais, avós, cuidadores — contra coqueluche, influenza, sarampo e difteria. O sistema público já oferece essas vacinas. O desafio é convencer os adultos de que eles também precisam delas.
A queda na cobertura vacinal, iniciada durante a pandemia de COVID-19 e nunca plenamente revertida, está diretamente ligada ao ressurgimento da coqueluche. O epidemiologista Fernando Rodrigues Bellissimo reforça que o aleitamento materno transfere anticorpos importantes ao bebê, mas deixa claro: a amamentação complementa a vacinação, não a substitui.
Na prática, a barreira é menos médica do que cotidiana. Karina Bordonal Gomiero Biagiotti, que atua em uma clínica privada de vacinação, observa que pais chegam preocupados com o calendário vacinal do filho, mas raramente pensam no próprio. Quando o custo entra em cena — cerca de 200 reais por dose —, a decisão se torna ainda mais difícil para muitas famílias. Biagiotti argumenta que uma dose dura aproximadamente uma década, e que o preço da proteção é incomparavelmente menor do que o custo de ver doenças evitáveis retornarem, surto após surto, a uma população que quase havia esquecido delas.
Brazil is watching diseases it thought it had conquered begin to circle back. In 2024 alone, nearly 7,800 people contracted whooping cough—a jump of more than 7,500 cases from the year before, when the country was already grappling with an outbreak. The culprit, according to health experts, is straightforward and preventable: too many adults around newborns are not vaccinated.
Infants under six months old are defenseless against these diseases. Their immune systems are still forming. Their lungs and airways lack the structural maturity to fight off infection. A baby that small cannot mount an effective immune response to whooping cough, measles, influenza, or diphtheria—not because of what they lack in will, but because of what they lack in biology. Jorgete Maria e Silva, a pediatrician at the Hospital das Clínicas of the University of São Paulo's Ribeirão Preto medical school, explains it plainly: the younger the child, the harder their body struggles to respond to disease, both from lack of prior immunity and from the simple anatomical fact of how their respiratory tract is built.
The solution sounds almost too simple. Vaccinate the adults. Vaccinate the parents, the grandparents, the caregivers—everyone in the immediate circle around a newborn. This approach, called the "cocoon strategy," emerged from a specific worry about whooping cough transmission, but Silva argues it should extend further. The public health system in Brazil already offers vaccines against influenza, measles, and diphtheria. Why not use them? Why not protect infants through the immunity of those who hold them?
But the strategy runs into a wall that has only grown higher since the pandemic. Vaccination coverage has collapsed. The resurgence of whooping cough over the past two years is directly tied to this decline—a decline that began during COVID-19 and never fully recovered. Silva points to a pattern: whooping cough follows a rhythm, with major outbreaks every three to five years. If vaccination rates had held steady between 2021 and 2022, the outbreak that arrived in late 2023 might never have happened. Instead, the system is now playing catch-up against a disease that should have been contained.
Breastfeeding offers some protection. Breast milk transfers antibodies directly to an infant, especially antibodies against diseases the mother herself was vaccinated against. Fernando Rodrigues Bellissimo, an epidemiologist at the same university, emphasizes this as a genuine tool. But he is careful to add a crucial caveat: breastfeeding is important, but it does not replace vaccination. It supplements it.
The barrier to adult vaccination, though, is often not medical—it is practical. Karina Bordonal Gomiero Biagiotti works at a private vaccination clinic and watches this play out daily. Parents arrive concerned about their baby's immunization schedule. She asks about their own vaccines. They say theirs are up to date and move on. They do not think about themselves. When cost enters the conversation, the decision becomes even simpler: vaccines run around 200 reais each. For many families, that is too much. The long-term calculus—protecting both yourself and your child—loses to the immediate expense.
Biagiotti's message to those families is direct. Yes, a vaccine costs money. Yes, it stings. But a dose lasts roughly a decade. The price of protection, she argues, is worth paying to keep a newborn safe. The alternative is watching preventable diseases return, one outbreak at a time, to a population that had nearly forgotten them.
Citas Notables
The younger the child, the more difficulties they have in responding positively to disease, both from lack of prior immunity and from the anatomical and physiological conditions of the respiratory tract.— Jorgete Maria e Silva, pediatrician at USP's Ribeirão Preto medical school
If there had been good vaccine adherence between 2021 and 2022, we would not have had an outbreak in late 2023.— Jorgete Maria e Silva
La Conversación del Hearth Otra perspectiva de la historia
Why does a baby's age matter so much here? Can't a six-month-old fight off whooping cough better than a newborn?
The difference is structural. A newborn's lungs and airways are still developing. They lack the physical architecture to clear infection effectively. It's not just about immunity—it's about how their body is built.
So vaccinating the mother helps because of breast milk?
It helps, yes. The antibodies transfer directly. But that's a supplement, not a replacement. You still need the people around the baby vaccinated too.
The cocoon strategy—is that new?
The idea emerged specifically because of whooping cough, but it's really just common sense applied systematically. Protect the vulnerable by vaccinating everyone near them.
What happened to vaccination rates? They were fine before.
COVID disrupted everything. People stopped going to clinics. Coverage dropped and never came back. Now we're seeing diseases resurge that we thought were controlled.
Why don't parents just vaccinate themselves?
Cost is part of it—200 reais is real money for many families. But there's also a mindset issue. Parents focus entirely on the baby and forget about their own protection.
Can this be fixed quickly?
Not quickly. Whooping cough cycles every three to five years. If coverage had stayed high, we'd have avoided the recent outbreak. Now we're trying to rebuild what we lost.