Age: 0.2
Sex: U
Vaccine: DTP
Symptoms: Death, Pertussis
Clinical narrative: This case was reported in a literature article and described the occurrence of death nos in a 2-month-old subject of unspecified gender who was vaccinated with DTP (manufacturer unspecified). The subject was born prematurely at 28 weeks' gestational age. On an unspecified date, the subject received 1st dose of DTP (unknown route of administration, unknown site of injection, batch number not provided). 15 days after vaccination with DTP, the subject experienced pertussis. The subject died from unknown cause of death. It was unknown whether an autopsy was performed. Summary of literature article: Pertussis is an endemic, underdiagnosed bacterial respiratory tract infection caused by Bordetella pertussis. The incidence of pertussis is cyclical, with peaks every 2-5 years as the proportion of susceptible people in the population who are immunologically naive or have lost immunity grows sufficiently large. The incidence of pertussis reported decreased substantially after extensive childhood immunization, falling from more than 265 000 cases in 1934 to a nadir of 1010 cases in 1976. Subsequently, the number of report cases has increased. During the cyclical peak year of 2005, more than 25 000 cases were reported, including more than 3000 cases; cases included 8 deaths in infants younger than 3 months. Possible explanations for the rising incidence of pertussis include large birth cohorts of susceptible infants, the replacement of more reactogenic whole cell vaccines with less effective acellular pertussis vaccines in the 1990s, more rapid waning of immunity conveyed by acellular pertussis vaccines, and increased detection of cases; and increased detection of cases through greater clinician awareness and the availability of more sensitive polymerase chain reaction (PCR) tests for laboratory confirmation. Pertussis PCR tests have been used since the 1990s and became the predominant testing method in 2004. In 2010, experienced the highest number of pertussis cases in more than 60 years, with more than 9000 cases, 809 hospitalizations, and 10 deaths. This report provides a descriptive epidemiolgic analysis of this epidemic and describes public health mitigation strategies that were used, including expanded pertussis vaccine recommendations. Clinical and demographic information were evaluated for all pertussis cases with onset from January 1, 2010, through December 31, 2010, and reported to the Department of Public Health. A total of 9154 pertussis cases with onset in 2010 were reported: 5482 (60%) confirmed, 1706 (19%) probable, and 1966 (22%) suspect. Of the confirmed cases, most (82%) were laboratory-confirmed by PCR testing, 6% were confirmed by culture, and the remaining 12% were epidemiologically linked to a laboratory-confirmed case. Of the suspected cases, 88% were confirmed by PCR testing and the remaining were epidemiologically linked to confirmed cases. The majority (56%) of reported patients became ill from June through September 2010; the peak month was July. The reported incidence of cases per 100 000 population was 23.4 statewide but varied 0-138.4 by county. Incidence was highest among infants younger than 6 months and lowest in adults 19 years of age and older. Relatively high numbers of cases were observed in fully vaccinated older children and adolescents, with the peak at age 10 years; after age 10, the number of cases declined with age and remained low among those aged 14-18 years. Information was reported for 8028 (88%) cases. Overall, the incidence per 100 000 population. Infants younger than 6 months had the highest case incidence (587.7 per 100 000); however, among young children and adolescents aged 1-18 years, the highest incidence (70.3). A total of 809 (8.9%) patients were hospitalized, of whom 584 (72%) were younger than 6 months and 446 (55%) were younger than 3 months. Sixty-two percent of all 720 infants younger than 3 months were hospitalized. The hospitalization rate among all infants younger than 6 months was 46%. The median age at disease onset among all hospitalized cases was 2.6 months (range less than 1 month to 92 years), and the median length of stay was 4 days (range 1-48 days). Of 1506 patients reported to have undergone radiography or computed tomography of the chest, 285 (18%) had a diagnosis of pneumonia. Nineteen patients had seizures and 3 had acute encephalopathy. Ten fatal cases were reported, all in infants. Nine were previously healthy infants younger than 2 months at illness onset who had not been immunized against pertussis; 7 of these infants were younger than 6 weeks. The remaining fatality was a 2-month-old infant born prematurely at 28 weeks' gestational age who had received the first dose of DTAP 15 days prior to disease onset. Nine of 10 fatalities were infants. The case-fatality rate among infants younger than 3 months was 1.3%. Seven infants were brought to medical attention for their pertussis illness at least once prior to the visit that led to hospital admission. Five of these 7 infants had multiple prior medical visits; however, only 1 received macrolide antibiotic therapy for pertussis. All had leukocytosis with a median white blood cell count of 78 200 cells/mm3. All deaths occurred in infants with symptom onset in the first 9 months of 2010. Of 4415 (76%) pediatric cases in infants aged 6 months through 18 years with vaccination information, 380 (9%) were completely unvaccinated against pertussis and 1621 (37%) had not received 1 or more recommended pertussis vaccine doses; 745 (46%) of incompletely immunized individuals were 11-18 years old and had not received TDAP. The remaining 2414 (55%) were reported to be fully immunized for their age; most (66%) of these were children aged 7-10 years who had received 5 prior doses of DTAP immunized younger than the recommended age for immunization with TDAP. Among 314 unvaccinated patients aged 6 month to 18 years. Infants younger than 6 months had the highest disease rates; all deaths and most hospitalizations occurred in infants younger than 3 months. Most pediatric cases were vaccinated according to national recommendations, although 9% of those aged 6 months to 18 years were completely unvaccinated again pertussis. High disease rates also were observed in fully vaccinated preadolescents, especially 10-year-olds. Mitigation strategies included expanded tetanus, diphtheria, and acellular pertussis vaccine recommendations, public and provider education, distribution of free vaccine for postpartum women and contacts of infants, and clinical guidance on diagnosis and treatment of pertussis in young infants. In conclusion, infants too young to be fully vaccinated against pertussis remain at highest risk of severe disease and death. Data are needed to evaluate strategies offering direct protection of this vulnerable population, such as immunization of pregnant women and of newborns. The high rate of disease among preadolescents suggests waning of immunity from the diphtheria, tetanus, and acellular pertussis series; additional studies are warranted to evaluate the efficacy and duration of protection of the diphtheria, tetanus, and acellular pertussis series and the tetanus, diphtheria, and acellular pertussis series.