Evaluation of Olfactory Function in Asymptomatic Children With Congenital Cytomegalovirus Infection

Background and aim Congenital cytomegalovirus (cCMV) is the most prevalent congenital infection worldwide, associated with numerous long-term sequelae, even in infants asymptomatic at birth. However, data are lacking for asymptomatic-at-birth children, who account for the majority of cases. Thus, the aim of the study was to evaluate the olfactory function of asymptomatic cCMV-infected children and compare it to matched healthy controls using a validated odor Identification test. Methods A case-control study was conducted. Asymptomatic cCMV-infected children and healthy controls without cCMV history over the age of five were included. Cases and controls were matched at a 1:2 ratio for age and sex. Exclusion criteria included other conditions associated with transient or permanent olfactory dysfunction. A U-Sniff odor identification test (Kids Ident Test "U-Sniff"; Burghart Messtechnik GmbH, Holm, Pinneberg, Germany) was used to evaluate olfaction. Statistical analysis was conducted using IBM SPSS Statistics for Windows, version 25.0 (IBM Corp., Armonk, New York, United States). Results Overall, 63 children were included (61.9% females; median age: 7 years). No differences in olfactory function (p=0.657) or olfactory score percentile (p=0.853) were detected between cases and controls. No differences in olfactory function or olfactory score percentile were detected in two sub-analyses, where participants were stratified according to age group (5-8 years old; p=0.545 and p=0.472, respectively, and 9-11 years old; p=1.000 and p=0.088, respectively) and COVID-19 infection history (positive history; p=0.645 and p=0.694, respectively, and negative history (p=not computable and p=0.509, respectively). Conclusions Olfactory function of children with cCMV infection who were asymptomatic at birth does not seem to differ from healthy sex-and-age-matched controls.