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

Heinonen, Santtu; Helve, Otto; Andersson, Sture; Janér, Cecilia; Süvari, Liina; Kaskinen, Anu

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.