Impact of extending the timing of maternal pertussis vaccination on hospitalized infant pertussis in England, 2014 - 2018
Tessier, E.; Campbell, H.; Ribeiro, S.; Fry, N.K.; Brown, C.; Stowe, J.; Andrews, N.; Ramsay, M.; Amirthalingam, G.
Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America 2020
ISSN/ISBN: 1058-4838 PMID: 32569365 DOI: 10.1093/cid/ciaa836
In October 2012 a maternal pertussis vaccination program was introduced in England for women between 28 and 32 weeks of pregnancy. In April 2016, the recommended optimal window was extended to 20-32 weeks to improve vaccine coverage and protect preterm infants.This study assesses the impact of offering maternal pertussis vaccination earlier in pregnancy on hospitalized infant pertussis cases. Hospitalized pertussis cases ≤60 days old in England were extracted from Hospital Episode Statistics pre-policy change and post policy change. Data were linked to laboratory-confirmed cases and clinical records were reviewed where cases were not matched. Maternal vaccine status of identified cases was established. Median hospital duration was calculated, and a competing risk survival analysis undertaken to assess multiple factors. A total of 201 cases were included in the analysis. Of the 151 cases with reported gestational age, the number of hospitalizations amongst full-term infants was 60 cases pre-policy and 62 cases post policy, respectively while preterm cases declined from 20 to 9 (p=0.06). Length of hospital stay did not differ significantly after the policy change. Significantly longer hospital stays were seen in cases aged 0- 4 weeks (median of 3 more days than infants 5-8 weeks), premature infants (median of 4 more days than term infants) and cases with coinfections (median of 1 more day than those without coinfection). The number of preterm infants hospitalized with pertussis in England halved after the policy change and preterm infants were no longer over-represented amongst hospitalized cases.