Burger-Calderon R, Carrillo FB, Gresh L, et al. - Researchers examined a large cohort of pediatric Zika cases for delineating their clinical profiles and appraising the diagnostic performance of the WHO and PAHO case definitions. Encompassing the major 2016 Zika epidemic, participants were encouraged to visit the study health center at first indication of any illness from January 2016 to February 2017 in the Pediatric Dengue Cohort Study (PDCS) in Managua, Nicaragua. PDCS participants (aged 2–14 years) underwent molecular and serological assays when exhibited any of the following four broad clinical profiles suspected of resulting from symptomatic Zika virus infection: fever and at least two of headache, retro-orbital pain, myalgia, arthralgia, rash, hemorrhagic manifestations, and leukopenia; fever and at least two of nausea or vomiting, rash, aches and pains, positive tourniquet test, leukopenia, and any dengue warning sign; undifferentiated fever without evident cause, with or without any other clinical finding; and afebrile rash with or without any other clinical finding. In this work, the most thorough description of pediatric Zika to date was provided. Following a cohort of about 3,700 children, they assessed 556 laboratory-confirmed Zika and 548 non-Zika cases. The WHO case definition captured 176 confirmed Zika cases, and the PAHO definition 109 confirmed Zika cases, indicating that under the WHO and PAHO case definitions, most pediatric Zika cases go undetected. This suggests the necessity for a revision of current standards for Zika case ascertainment. Among Zika cases, the most common symptoms were rash (n = 440) — particularly generalized erythematous rash (n = 334) — fever (n = 333), leukopenia (n = 217), and headache (n = 203) and these symptoms peaked within 3 days of illness onset. Across pediatric age, increase in the sensitivity of Zika case definitions was observed (from 11·3% to 56·1% for the WHO case definition and from 6·0% to 36·6% for the PAHO case definition), as the prevalence of most clinical findings (particularly arthralgia) increased with age, irrespective of previous dengue virus infection. Consequently, Zika manifestations differed across pediatric age; a dengue-like clinical profile is presented by older Zika cases while undifferentiated fever or afebrile rash was present in younger Zika cases.