Paediatric infections: prevention of transmission and disease--implications for adults.

Congenital and neonatal viral infections usually display their acute manifestations in highly recognisable ways, for example, congenital rubella, cytomegalovirus (CMV), varicella, human immunodeficiency (HIV) and herpes simplex virus (HSV) infection. By contrast, congenital hepatitis B virus (HBV) infection may go undetected for years. Some of these are preventable, but what is not immediately apparent is that the long-term consequences are being prevented as well. The long-term consequences of congenital and neonatal infections include endocrine, immunological and cardiovascular disease, deafness, visual problems, intellectual handicap and cerebral palsy. With the survival of HIV-infected infants into adulthood the long-term consequences will soon be described. Maternally and neonatally transmitted HBV infection predisposes to carriage, liver cirrhosis and hepatocellular carcinoma in young adults. Neonatal HBV vaccination prevents adult cancer. Acquired viral infections may predispose to subsequent lung disease, malabsorption, fertility problems or neurological disability. In the prevention of acquired rubella, varicella, HBV, influenza, poliovirus, measles and hepatitis A, one should mention the added bonus of preventing secondary cases by preventing transmission from infants and children to other children and adults. Preventing paediatric HSV, HBV and HIV infection in females may even be preventing subsequent transmission to future generations. Turning to paediatric bacterial infections, vaccinating infants and young children against pertussis could not only prevent transmission to older children and adults but also break the cycle, which then transmits from adults back to infants and young children. There is evidence that disease in older age groups, including adults, has been prevented by virtue of herd immunity from paediatric vaccination, e.g. Neisseria meningitidis Group C and Streptococcus pneumoniae. The add-on benefits for other generations, including for adults, arising from the prevention of paediatric infections are considerable.