BACKGROUND: Pertussis is a vaccine-preventable illness that has been increasing in Texas. The increasing incidence is concerning as it can cause severe illness and occasionally death, especially in infants. Texas frequently has a higher than expected number of deaths from pertussis, especially compared to the number of deaths reported nationally. We reviewed ten years of data to identify trends in deaths from pertussis in Texas.
METHODS: Pertussis cases in Texas were classified according to the 1997 CSTE case definition until 2014 when Texas adopted the 2014 CSTE case definition. However, pertussis patients that do not meet the cough duration requirement of the case definition due to death or medical intervention (e.g. intubation) are counted as cases of pertussis in Texas if they are PCR positive or the death certificate lists pertussis as a cause of death. Reported cases or their proxies are interviewed using a standard investigation form. Information collected is entered into NEDSS. Data analysis was performed using Excel. Age at date of cough onset was calculated.
RESULTS: From 2005-2014, 33 deaths from pertussis were reported in Texas, with 0-10 deaths reported per year. Children under two months of age accounted for 87.9% of deaths. The remaining cases were 2, 3, 14 and 81 years of age. The overall case fatality rate (CFR) was 0.2%, but in cases under two months of age, the CFR was 1.7%. Sixteen (48.5%) of the deaths were in females. Deceased pertussis cases were predominantly Hispanic (61%), however 35.7% of pertussis cases over the same years were Hispanic. Of the four patients old enough for vaccine, one was vaccinated, one was never offered vaccine, one had a contraindication, and one refused. Ten (30.3%) of the cases had a suspected source case identified. A parent was identified 60.0% of the time, siblings 20.0%, and other relative 20.0%. None of the patients that died, however, were epi-linked to a laboratory-confirmed case of pertussis. Fifteen cases (45.5%) that died did not meet the standard CSTE case definition. Nine (60.0%) expired before 14 days had passed after cough onset, and six (40.0%) had medical intervention within 14 days of cough onset.
CONCLUSIONS: The higher than expected number of deaths in Texas may reflect the deviation from the CSTE case definition. The disparity between disease incidence and mortality in the Hispanic population indicates an opportunity for prevention messages in Hispanic communities, especially messaging promoting maternal vaccination.