Babies benefitting from increased herd immunity
CONGENITAL and neonatal varicella have become rare in Australia since chickenpox vaccination was put on the National Immunisation Program (NIP), according to new research.
The first study of the impact of universal vaccination on rates of infection in babies suggests they are being protected by increased herd immunity, the authors said.
Data collected by the Australian Paediatric Surveillance Unit showed the incidence of neonatal varicella dropped from 5.8 per 100,000 live births per year prior to availability of the vaccine, to an estimated 2.05 per 100,000 after it was included in the NIP in November 2005.
Researchers from the National Centre for Immunisation Research and Surveillance and paediatric centres in six states found that in the four years to 2009, there were 16 cases of neonatal varicella reported – a reduction of 85% compared with the pre-vaccination era.
Congenital varicella also declined – by a nonsignificant