Decreased risk of COVID-19 pneumonia in children and adolescents during the Delta variant emergence

E Murillo-Zamora; X Trujillo; M Huerta; M Ríos-Silva; L M Baltazar-Rodríguez; J Guzmán-Esquivel; V Benites-Godínez; A D Ortega-Ramírez; O Mendoza-Cano

doi:10.1016/j.puhe.2021.12.017

Decreased risk of COVID-19 pneumonia in children and adolescents during the Delta variant emergence

Public Health. 2022 Mar:204:9-11. doi: 10.1016/j.puhe.2021.12.017. Epub 2021 Dec 28.

Authors

E Murillo-Zamora¹, X Trujillo², M Huerta², M Ríos-Silva³, L M Baltazar-Rodríguez⁴, J Guzmán-Esquivel⁵, V Benites-Godínez⁶, A D Ortega-Ramírez⁷, O Mendoza-Cano⁸

Affiliations

¹ Departamento de Epidemiología, Unidad de Medicina Familiar No. 19, Instituto Mexicano Del Seguro Social, Av. Javier Mina 301, Col. Centro, C.P. 28000, Colima, México; Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Col. Las Víboras, C.P. 28040, Colima, México. Electronic address: [email protected].
² Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Col. Villas San Sebastián, C.P. 28045, Colima, México.
³ Universidad de Colima - CONACyT, Centro Universitario de Investigaciones Biomédicas, Av. 25 de Julio 965, Col. Villas San Sebastián, C.P. 28045, Colima, México.
⁴ Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Col. Las Víboras, C.P. 28040, Colima, México.
⁵ Facultad de Medicina, Universidad de Colima, Av. Universidad 333, Col. Las Víboras, C.P. 28040, Colima, México; Unidad de Investigación en Epidemiología Clínica, Instituto Mexicano Del Seguro Social, Av. de Los Maestros 149, Col. Centro, C.P. 28000, Colima, México. Electronic address: [email protected].
⁶ Coordinación de Educación en Salud, Instituto Mexicano Del Seguro Social, Calzada Del Ejercito Nacional 14, Col. Fray Junípero Serra, C.P. 63160, Tepic, Nayarit, Mexico. Electronic address: [email protected].
⁷ Programa de Posgrado en Ciencias Médicas, Facultad de Medicina, Universidad de Colima Av. Universidad 333, Col. Las Víboras, C.P. 28040, Colima, México. Electronic address: [email protected].
⁸ Facultad de Ingeniería Civil, Universidad de Colima, Km. 9 Carretera Colima-Coquimatlán, Coquimatlán, C.P. 28400, Colima, México. Electronic address: [email protected].

Abstract

Objectives: This study aimed to evaluate factors associated with the risk of COVID-19 pneumonia in children (aged <10 years) and adolescents (aged 10-19 years) before (March 2020-April 2021) and during (May-July 2021) the Delta (B.1.617.2) variant emergence.

Study design: A retrospective and nationwide cohort study was conducted in Mexico.

Methods: Data from 26,961 laboratory-confirmed cases of COVID-19 were analyzed. Risk ratios (RRs) and 95% confidence intervals (CIs) were used to evaluate the association of the evaluated exposures with the risk of COVID-19 pneumonia.

Results: The overall incidence rate of pneumonia was 23.0 per 10,000 person-days, and it was lower during the Delta variant emergence (30.3 vs. 9.4 person-days, p < 0.001). In multiple analysis, a decreased risk of pneumonia was observed among those cases occurring in May 2021 or later (vs. March 2020-April 2021, RR = 0.98, 95% CI 0.97-0.99) and among older patients (RR_{per year} = 0.998, 95% CI 0.996-0.998). Other comorbidities (namely, obesity, chronic kidney disease, diabetes mellitus, immunosuppression, or malignant tumors) were associated with an increased risk of severe COVID-19 manifestations.

Conclusions: Our findings suggest that during the Delta variant emergence, children and adolescent patients were at reduced risk of COVID-19 pneumonia in Mexico. Further research is needed to identify factors determining the observed scenario.

Keywords: Adolescent; COVID-19; Child; Pneumonia; SARS-CoV-2.

MeSH terms

Adolescent
Adult
COVID-19* / epidemiology
Child
Cohort Studies
Humans
Pneumonia* / epidemiology
Retrospective Studies
Risk Factors
SARS-CoV-2
Young Adult

Supplementary concepts

SARS-CoV-2 variants