Dataset Information

Burden of Children Hospitalized With Pertussis in Canada in the Acellular Pertussis Vaccine Era, 1999-2015.

ABSTRACT:

Background

Recent increases in pertussis morbidity and mortality rates among young infants have led to a recommendation in some countries for vaccination against pertussis during pregnancy. Having data on the burden of pediatric pertussis in a large population over time is important for establishing the true burden of disease in the acellular pertussis (aP) vaccine era. Here, we describe age-specific epidemiology and morbidity and mortality rates in children hospitalized with pertussis over 17 years across Canada in the aP vaccine era.

Methods

Patients aged ≤16 years who were admitted to 1 of 12 pediatric tertiary-care hospitals across Canada between 1999 and 2015 with confirmed (laboratory-confirmed or epidemiologically linked) or probable (clinically diagnosed) pertussis were included.

Results

Overall, 1402 patients with pertussis were included. Infants aged <2 months had the highest mean annual incidences of pertussis hospitalization and intensive care unit (ICU) admission (116.40 [95% confidence interval (CI), 85.32-147.49] and 33.48 [95% CI, 26.35-40.62] per 100 000 population, respectively). The overall proportion of children who required ICU admission was 25.46%, and the proportion was highest in infants aged <2 months (37.90%). Over the span of this study, 21 deaths occurred. Age of <16 weeks, prematurity, encephalopathy, and a confirmed pertussis diagnosis were independent risk factors for ICU admission. Age of <4 weeks, prematurity, and female sex were independent risk factors for death.

Conclusions

In the aP vaccine era, endemic pertussis still contributes considerably to childhood morbidity and death, particularly in infants aged <2 months. Vaccination against pertussis during pregnancy has the potential to reduce this disease burden.

SUBMITTER: Abu-Raya B

PROVIDER: S-EPMC7192396 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceIn most countries, the diphtheria-tetanus-acellular pertussis (DTaP) vaccine is administered as a 3-dose infant series followed by additional booster doses in the first 5 years of life. Short-term immunity from the DTaP vaccine can depend on the number, timing, and interval between doses. Not receiving doses in a timely manner might be associated with a higher pertussis risk.ObjectiveTo examine the association between number and timeliness of vaccine doses and age-specific pertussis risk.Design, setting, and participantsThis population-based, retrospective cohort study used Washington State Immunization Information System data and pertussis surveillance data from Public Health Seattle and King County, Washington. Included participants were children aged 3 months to 9 years born or living in King County, Washington, between January 1, 2008, and December 31, 2017. Data were analyzed from June 30 to December 1, 2019.ExposuresBeing undervaccinated (receiving fewer than recommended doses at a given age) or delayed vaccination (not receiving doses within time frames recommended by Centers for Disease Control and Prevention).Main outcomes and measuresSuspected, probable, and confirmed pertussis diagnosis.ResultsA total of 316 404 children (median age, 65.2 months [interquartile range, 35.3-94.1 months]; 162 025 boys [51.2%]) as of December 31, 2017, with 17.4 million person-months of follow-up were included in the analysis. A total of 19 943 children (6.3%) had no vaccines recorded in the Immunization Information System, 116 193 (36.7%) received a vaccine with a delay, and 180 268 (56.9%) were fully vaccinated with no delay. Delayed vaccination and undervaccination rates were higher for older children (17.6% delayed or undervaccinated at age 2 months for dose 1 at 3 months vs 41.6% at age 5 years for dose 5) but improved for successive birth cohorts (52.2% for 2008 birth cohort vs 32.3% for 2017 birth cohort). Undervaccination was significantly associated with higher risk of pertussis for the 3-dose primary series (adjusted relative risk [aRR], 4.8; 95% CI, 3.1-7.6), the first booster (aRR, 3.2; 95% CI, 2.3-4.5), and the second booster (aRR, 4.6; 95% CI, 2.6-8.2). However, delay in vaccination among children who received the recommended number of vaccine doses was not associated with pertussis risk.Conclusions and relevanceThe results of this cohort study suggest that undervaccination is associated with higher pertussis risk. Short delays in vaccine receipt may be less important if the age-appropriate number of doses is administered, but delaying doses is not recommended. Ensuring that children receive all doses of pertussis vaccine, even if there is some delay, is important.

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