RESUMO A febre amarela é uma doença sistêmica que estava controlada graças às efetivas campanhas de combate ao vetor e aos programas de vacinação. Porém, desde 1999, os surtos reiniciaram-se, devido à ineficácia do controle do vetor, levando à necessidade da imunização em larga escala contra o vírus da febre amarela, gerando aumento do risco de ocorrência de reação adversa à vacina. O presente estudo se propôs a relatar o caso de um lactente previamente saudável, que procurou pronto atendimento, pois, há 3 dias, apresentava febre, calafrios, náusea e vômitos. Em 24 horas após medidas de suporte e alta, evoluiu com queda do estado geral, estrabismo, falta de controle da musculatura cervical e redução da força muscular de membros inferiores. O caderno vacinal encontrava-se completo, tendo recebido vacina contra febre amarela há 20 dias. Durante a internação, foi realizada coleta do liquor, e foram administrados ceftriaxona e aciclovir. Após cultura negativa do liquor, o antibiótico foi suspenso. A tomografia computadorizada de crânio não apresentou alterações. Solicitou-se pesquisa de anticorpos contra o vírus da febre amarela no liquor, sendo positiva para IgM e confirmando a doença neurotrópica associada à vacina da febre amarela. A partir do quinto dia de internação, o paciente evoluiu com melhora do estrabismo, do tônus cervical e da força muscular. No décimo dia de internação, apresentou melhora completa do quadro, sem alterações laboratoriais, recebendo alta. A vacina contra febre amarela é segura, eficaz e fortemente recomendada, porém não está completamente isenta de reações adversas graves, inclusive podendo levar a quadros fatais.

ABSTRACT The yellow fever is a systemic disease that was under control due to the effective campaigns against the vector and promotion of vaccines programs. However, since 1999, outbreaks appeared because of inefficient control of the vector, and led to the need of amplifying the immunization in large scale against the yellow fever virus, and consequently, raising the risk of adverse reactions to the vaccine. We report a case of previously healthy infant, who was referred to our care service, after 3 days with fever, chills, nausea and vomits, he received support therapy and was discharged from the hospital. After 24 hours of supportive measures, he was discharge. The patient returned to our service with general condition decline, strabismus, inability to control of cervical musculature and reduced force of the legs. The patient vaccine had received all vaccines from the calendar, and he was vaccinated for yellow fever 20 days before symptoms. During the hospitalization, liquor was collected, and ceftriaxone and aciclovir were administered. After negative cultures from the liquor, the antibiotics were suspended. The computed tomography of patient’s brain showed no alterations. Research for antibodies against yellow fever was requested, being positive for IgM in the liquor, and confirming the neurotropic disease associated with the yellow fever vaccine. On the fifth day of hospitalization, the patient showed improvement on the strabismus, cervical tonus, and musculature force. On the tenth day of hospitalization, patient showed complete improvement, and his laboratory exams no alterations. Subsequently, patient was discharged. The vaccine against yellow fever is safe, efficient and highly recommended, however it is not completely free from serious adverse reactions, including death.