Reduced Severity of Pertussis in Persons With Age-Appropriate Pertussis Vaccination—United States, 2010–2012

Abstract

Background In 2012, over 48,000 pertussis cases were reported in the United States. Many cases occurred in vaccinated persons, showing that pertussis vaccination does not prevent all pertussis cases. However, pertussis vaccination may have an impact on disease severity. Methods We analyzed data on probable and confirmed pertussis cases reported through Enhanced Pertussis Surveillance (Emerging Infections Program Network) between 2010 and 2012. Surveillance data were collected through physician and patient interview and vaccine registries. We assessed whether having received an age-appropriate number of pertussis vaccines (AAV) (for persons aged ≥3 months) was associated with reduced odds of post-tussive vomiting, a marker of more clinically significant illness, or of severe pertussis (seizure, encephalopathy, pneumonia, and/or hospitalization). Adjusted odds ratios (aOR) were calculated using multivariable logistic regression. Results Among 9,801 pertussis patients aged ≥3 months, 77.6% were AAV. AAV status was associated with a 60% reduction in odds of severe disease in children 7 months–6 years old in multivariable logistic regression and a 30% reduction in odds of post-tussive vomiting in persons aged 19 months–64 years. Conclusions Serious pertussis symptoms and complications are less common among AAV pertussis patients, demonstrating that the positive impact of pertussis vaccination extends beyond decreasing risk of disease.

Evaluating the role of cough duration in the pertussis case definition among Michigan cases, 2000–2010

“…The initial healthcare visit date was based on the earliest reported date of antibiotic prescription, as this was the most complete variable. Because only two cases were reported to not be taking antibiotics, our analysis represented findings from a population that almost always received antibiotics on their first medical visit, which is consistent with pertussis reporting from other surveillance systems (Baggett et al, 2007; McNamara et al, 2017).…”

“…Infants typically present with more severe illness sometimes resulting in hospitalization, and accounting for 53% of the 160,700 global pertussis-associated deaths. (Yeung et al, 2017) The severity of illness can be mitigated with the use of antibiotics (Carlsson et al, 2015) and prevented through age-appropriate immunization with a four-dose primary series beginning at two months of age, followed by booster doses as the child ages (McNamara et al, 2017; Robinson, 2016; Folkhälsomyndigheten, 2018)…”

Outbreak investigation of pertussis in an elementary school: a case-control study among vaccinated students

“…Thus, most of the cases in this outbreak have a mild symptom such as cough without inspiratory whoop, which has consistent finding of a previous study that the pertussis vaccination has a positive effect to reduce the risk of severe progress [ 14 ]. However, pertussis vaccination does not prevent all pertussis cases [ 15 ]; although the vaccination is also likely to affect the substantial reduction in the rate at which pertussis is transmitted to other students.…”

Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP)

“…Although it is unclear if these animal models fully represent human disease, expert opinion is that persons vaccinated with acellular pertussis vaccines can become infected with and transmit B. pertussis ( 158 , 159 ). Persons up to date with pertussis vaccines are less likely to have severe disease compared with those not up to date ( 160 ). Although it is presumed that vaccinated persons with less severe disease would be less likely to transmit B. pertussis because of less frequent or severe coughing, more recent evidence suggests that vaccination with acellular pertussis vaccines does not prevent transmission and therefore does not afford indirect protection against pertussis ( 155 – 157 ).…”

“…Recent epidemiologic and animal model evidence suggests that Tdap vaccination does not prevent transmission and therefore does not afford indirect protection of close contacts against pertussis ( 155 , 156 , 159 ). However, persons who are up to date with pertussis vaccines and who become infected generally have a milder infection compared with those who have not been vaccinated, which might make them less efficient in transmitting pertussis to others ( 160 ).…”