Olfactory function in congenital cytomegalovirus infection: a prospective study

Congenital cytomegalovirus (CMV) infection leads to olfactory bulb lesions in the fetus, yet little is known about its impact on olfaction after birth. Here, we have assessed in a prospective study conducted on children in two French hospitals from 2016 to 2019, infection severity and olfactory performance after congenital CMV infection. Children with congenital CMV infection aged 3 to 10 years and healthy controls (CTL) matched for age and sex to CMV children symptomatic at birth (sCMV) were enrolled. Olfactory discrimination was assessed using mono-odorants and binary mixtures. Data were analyzed for 54 children with PCR-confirmed congenital CMV infection, including 34 sCMV (median [IQR] age, 6 [5–8] years; 19 [55.9%] male), and 20 CMV asymptomatic at birth (aCMV, median [IQR] age, 4 [3–6] years; 12 [60.0%] male). sCMV were compared to 34 CTL children. Olfactory scores in CMV-infected children were independent from vestibular deficit and hearing loss. The olfactory score was efficient to discriminate between CTL and sCMV for children > 6 years (area under the receiver-operating characteristic curve (AUC, 0.85; P = 0.0006), but not for children < 7 years. For children > 6 years, the proportion of children with total olfactory score < 4 differed between sCMV and CTL groups (91.2% and 18.7%, P < 0.001), but not between aCMV and age-matched healthy control groups. Conclusion: Congenital CMV infection is associated with reduced olfactory performance in children with infection symptoms at birth. Clinical trial registration: NCT02782988 (registration date: May 26, 2016). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00431-022-04375-1.