Australian Paediatric Surveillance Unit (APSU) Annual Surveillance Report 2022.

For 30 years the Australian Paediatric Surveillance Unit (APSU) has conducted national surveillance of rare communicable diseases and rare complications of communicable diseases. In this report, we describe the results of thirteen such studies surveyed by the APSU in 2022, including reported case numbers and incidence estimates, demographics, clinical features, management and short-term outcomes. Conditions described are: acute flaccid paralysis (AFP); congenital cytomegalovirus (cCMV); 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); congenital rubella infection/syndrome; congenital varicella syndrome (CVS) and neonatal varicella infection (NVI); and the new conditions dengue; Q fever; and severe acute hepatitis. In 2022, cases of severe complications of influenza were reported to the APSU for the first time since 2019. This likely reflects the easing of government-mandated restrictions imposed in 2020-2021 to curb the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the re-emergence of a range of infectious diseases. As previously, AFP surveillance by the APSU contributed to Australia achieving a minimum target incidence of one AFP case per 105 children aged less than 15 years. Cases of JoRRP and NVI were reported in 2022. This indicates potential gaps in human papillomavirus (HPV) and varicella vaccination coverage respectively, especially in high-risk groups such as young migrant and refugee women of childbearing age from countries without universal vaccination programs. Paediatric HIV case numbers resulting from mother-to-child-transmission (MTCT) of HIV remain low in Australia due to use of effective intervention strategies. However, there has been an increase in the number of imported cases of HIV in children (mainly perinatally-acquired) from countries with a high HIV prevalence. Without effective vaccines, there has been no decline in the incidence of congenital CMV and neonatal HSV, indicating the importance of early identification and management to reduce morbidity and mortality. The first cases of dengue, Q fever and severe acute hepatitis were received by APSU in 2022, including two cases of acute hepatitis in which aetiology has not been confirmed to date. The APSU has an important ongoing role in monitoring rare childhood infections.