Neonatal invasive pneumococcal disease: New Zealand experience in the era of pneumococcal vaccination

Background: Invasive pneumococcal disease (IPD) became a notifiable disease in New Zealand in 2008, and in the same year pneumococcal conjugate vaccine (PCV) was added to the childhood immunisation schedule. Design: This was a retrospective study of IPD in infants aged <90 days reported to the national notifiable disease database, EpiSurv, from 1 January 2009 to 31 December 2013. All cases had Streptococcus pneumoniae isolated from a normally sterile site. Main outcome measures: IPD incidence was calculated for babies aged <90 and <30 days using the number of national IPD cases with a denominator of annual infant live births. Clinical, demographic and outcome data were reviewed for infants aged less than seven days (early onset). Results: There were 29 cases of IPD in infants aged <90 days and 19 cases in infants aged <30 days. Of the nine early-onset cases, six occurred within the first 48 h. Six of the early-onset cases were infants of NZ Maori ethnicity. One infant died six hours after birth. Three infants developed long-term neurological or respiratory sequelae. Isolates from five of the early-onset cases were S. pneumoniae serotypes not covered by the PCV in use at the time of infection. Maternal vaccination with 23-valent pneumococcal vaccine would have covered 84% (16 of 19) of serotypes responsible for the cases in infants <30 days old. Conclusion: Strategies such as maternal vaccination or accelerated neonatal vaccination may be beneficial to protect neonates at high risk of IPD.