Australian Paediatric Surveillance Unit (APSU) Annual Surveillance Report 2023.

The Australian Paediatric Surveillance Unit (APSU) has been conducting prospective national surveillance of rare communicable diseases, and complications of communicable diseases, of childhood and infancy for more than three decades. In 2023, there were 15 communicable diseases and complications of communicable diseases under APSU surveillance, which included: acute flaccid paralysis (AFP), congenital cytomegalovirus (cCMV), dengue, severe acute hepatitis (SAH), neonatal and infant herpes simplex virus (HSV) infection, perinatal exposure to human immunodeficiency virus (HIV) and paediatric HIV infection, severe complications of influenza, juvenile-onset recurrent respiratory papillomatosis (JoRRP), Q fever, congenital rubella infection/syndrome, congenital varicella syndrome (CVS) and neonatal varicella infection (NVI), as well as two new communicable diseases, which were paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) and Japanese encephalitis virus (JEV) infection. The results of 2023 APSU surveillance show a marked increase in severe influenza cases for the first time in five years, with more complications associated with influenza type B. Moreover, one child died and only 6% of children received a seasonal influenza vaccine. The APSU also received reports of cases of rare emerging diseases: dengue, Q fever and PIMS-TS. Furthermore, our results show a persistence of vaccine-preventable JoRRP, mother-to-child transmission of HIV, and deaths from neonatal HSV.