Between 1947 and 1980 vaccination against pertussis was effective in lowering Texas pertussis cases by 99%. Since the 1980s, however, Texas has seen an increase in pertussis. In 2009, Texas had 3358 cases, the most since 1959. Of those cases, 290 were hospitalized, 252 of whom were under 12 months old.
To analyze risk factors for hospitalization due to pertussis.
Medical providers, schools, laboratories, and the public report suspected pertussis cases to health departments. Health department staff then investigate and collect data on the clinical symptoms, demographic characteristics, potential contacts, and vaccination status for each case. Investigations are then entered into an electronic surveillance system. For this project, pertussis surveillance data from 2009 were extracted from the electronic surveillance system. Excel and EpiInfo were used to analyze the data. Cases were considered vaccinated if they had received one or more doses of a pertussis vaccine. Cases were considered “behind” if they did not meet the ACIP recommendations for their age. Eligible cases were defined as those eligible for the next dose in the series (ie a 4 month old with 1 dose). Cases were considered “up-to-date” if the cases met the ACIP recommendations for their age.
The risk of hospitalization for unvaccinated 2-11 month olds with pertussis was 2.16 (1.55<RR<3.02) times greater than that for their vaccinated counterparts. The risk of hospitalization for behind compared to up-to-date cases under 12 months old was insignificant. The hospitalization risk for eligible cases compared to their up-to-date counterparts was 2.16 (1.47<RR<3.18). Hispanics under 12 months with pertussis were 34% more likely to be hospitalized than their white counterparts (1.06<RR<1.68).
Even one dose of pertussis vaccine can reduce the risk of hospitalization from pertussis. Race/ethnicity may also be a factor in hospitalization risk.