Pertussis is a highly contagious respiratory disease caused by the bacterium Bordatella pertussis. Transmission occurs from person-to-person via air droplets from coughs or sneezes. The primary symptom is a persistent cough lasting more than 2 weeks. Vaccination is the best way to prevent pertussis. The recommended vaccine schedule includes 5 doses beginning at 2 months of age. Maternal immunization during the third trimester is recommended to protect infants ineligible for vaccination. Pertussis rates have recently shown a resurgence despite high vaccine coverage in the United States. This project aims to further understand the medical and socioeconomic factors related to pertussis.
METHODS:
Descriptive analytics were utilized to assess distribution of race, age, and other demographic factors of pertussis cases in Harris County excluding Houston. Cases were considered up to date (UTD) if all recommended doses were received by onset and not up to date (nUTD) if the recommended vaccine period lapsed without a dose. Cases were grouped into 5-year periods to help adjust for low case counts in some years. Poisson regression was used to analyze time trends. The remainder of the analyses followed the Public Health Disparities Geocoding Project methodology. Census data from 2000 and 2010 were used for the incidence rate denominators. The area-based socioeconomic measure used was “Percent of persons living below the poverty level” with the following cut points: 0-4.9%, 5.0-9.9%, 10.0-19.9%, and ≥20.0%.
RESULTS:
Reported annual case counts ranged from 7 to 126, and case age at onset varied from 6 days to 89 years, with infants as the majority. Non-Hispanic whites (44.20%) made up the largest percent of cases followed by Hispanic whites (36.56%). Infants were noted to have more frequent ER visits and hospitalizations than other age groups. Analysis of vaccine history showed 32.18% UTD, 16.40% nUTD, 14.56% ineligible due to age, and 36.86% unknown. Poisson regression exhibited significant increase in pertussis over the time periods. Poverty level analysis indicated greater reporting of pertussis in wealthier areas of Harris County.
CONCLUSIONS:
With increased reporting of pertussis in vaccinated and unvaccinated Harris County residents, consideration should be given to revisiting the currently recommended vaccination schedule, with additional research aimed at duration of vaccine efficacy. Strengthening cocooning strategies, promoting vaccination during pregnancy, and increasing overall vaccination rates in all income groups could further reduce disease burden.