Nasal expression of SARS-CoV-2 entry receptors in newborns

Background SARS-CoV-2 infection is typically mild in children. Lower expression of SARS-CoV-2 entry receptors in the nasal epithelia have been described in children compared with adults. However, data from newborns are lacking. We compared nasal expression of four SARS-CoV-2 entry receptors between term and preterm newborns and adults. Methods Nasal scrape samples were obtained from 28 newborns (17 term and 11 preterm) and 10 adults. Reverse-transcription quantitative PCR was used to measure mRNA expression of ACE2, transmembrane serine protease 2 (TMPRSS2), neuropilin 1 (NRP1) and neuropilin 2 (NRP2) and insulin-like growth factor 1 receptor (IGF1R). Results Expression levels of ACE2, TMPRSS2, NRP1 and NRP2 were lower in term and preterm newborns and IGF1R lower in term newborns compared with adults (p<0.05). Conclusions Both term and preterm newborns, compared with adults, have lower expression of SARS-CoV-2 entry receptors in nasal epithelium. Low nasal expression of SARS-CoV-2 entry receptors in newborns in both preterm and term cases may contribute to the low attack rates and mild disease in newborns.

Automated summary

Both term and preterm newborns exhibit lower expression levels of SARS-CoV-2 entry receptors in the nasal epithelium compared with adults. The low nasal expression of these receptors in newborns may contribute to the low attack rates and mild disease observed in this population.