Tagarro García, AlfredoSanz Santaeufemia, Francisco JoséGrasa, CarlosCobos Carrascosa, ElenaYebra Yebra, JuliaAlonso Cadenas, José AntonioBaquero Artigao, FernandoMesa Guzmán, Juan MiguelPérez Seoane, BeatrizEPICO-AEP Working GroupEt al.2022-07-082022-07-082022Tagarro, A., Sanz-Santaeufemia, F. J., Grasa, C., Cobos, E., Yebra, J., Alonso-Cadenas, J. A., Baquero-Artigao, F., Mesa, G. J., Pérez, S. B., Calvo, C., Herreros, M. L., Epalza, C., Melendo, S., Domínguez-Rodríguez, S., Vidal, P., Pacheco, M., Ballesteros, A., Bernardino, M., Villanueva-Medina, S., Rodríguez, M. P., … EPICO-AEP Working Group (2022). Dynamics of RT-PCR and Serologic Test Results in Children with SARS-CoV-2 Infection. The Journal of Pediatrics, 241, 126-132.E3. https://doi.org/10.1016/j.jpeds.2021.09.0290022-34761097-6833http://hdl.handle.net/11268/11441Objectives: To determine the time to reverse transcription-polymerase chain reaction (RT-PCR) negativity after the first positive RT-PCR test, factors associated with longer time to RT-PCR negativity, proportion of children seroconverting after proven severe acute respiratory syndrome coronavirus 2 infection, and factors associated with the lack of seroconversion. Study design: The Epidemiological Study of Coronavirus in Children of the Spanish Society of Pediatrics is a multicenter study conducted in Spanish children to assess the characteristics of coronavirus disease 2019. In a subset of patients, 3 serial RT-PCR tests on nasopharyngeal swab specimens were performed after the first RT-PCR test, and immunoglobulin G serology for severe acute respiratory syndrome coronavirus 2 antibodies was performed in the acute and follow-up (<14 and ≥14 days after diagnosis) phase. Results: In total, 324 patients were included in the study. The median time to RT-PCR negativity was 17 days (IQR, 8-29 days), and 35% of patients remained positive more than 4 weeks after the first RT-PCR test. The probability of RT-PCR negativity did not differ across groups defined by sex, disease severity, immunosuppressive drugs, or clinical phenotype. Globally, 24% of children failed to seroconvert after infection. Seroconversion was associated with hospitalization, persistence of RT-PCR positivity, and days of fever. Conclusions: Time to RT-PCR negativity was long, regardless of the severity of symptoms or other patient features. This finding should be considered when interpreting RT-PCR results in a child with symptoms, especially those with mild symptoms. Seroprevalence and postimmunization studies should consider that 11 in 4 infected children fail to seroconvert.engSerologíaCOVID-19journal article10.1016/j.jpeds.2021.09.029open accessPediatríaVirusEfectos fisiológicos