Authored by: Larry Kociolek, MD, MSCI, FSHEA, FPIDS, Danielle Zerr, MD, MPH, Jenn Schuster, MD, MSCI, Claudia Hoyer, MD, Doneen West, PharmD, MBA
Overview of Outbreak
The CDC announced that the number of pertussis cases are increasing across the United States. There are more than five times as many cases reported this year compared to 2023. Weekly pertussis surveillance data of nationally notifiable pertussis from the CDC indicates that there are already more cases in 2024 than what was seen in 2019, prior to the pandemic.
Globally, pertussis remains one of the leading causes of vaccine preventable deaths in children. Most pertussis deaths occur in young infants who are either unvaccinated or have not completed their vaccination series.
Transmission
Pertussis, also known as whooping cough, is a respiratory infection caused by Bordetella pertussis bacteria. Transmission occurs person-to-person through respiratory droplets or contact with airborne droplets. Symptoms normally develop within 5 to 10 days after exposure.
Symptoms
Clinical presentation may differ with age and immunity status. A pertussis illness is typically divided into three stages:
- Catarrhal stage: Patients will present with mild cough and runny nose, similar to viral upper respiratory infections. Low grade fever may be present. This stage typically lasts 1-2 weeks.
- Paroxysmal stage. Paroxysmal cough can occur and are sometimes associated with vomiting or a “whooping” sound with a significant inhalation at the end of the coughing fit. Unlike adolescents and adults, young children typically do not “whoop” with a coughing fit. Children are often exhausted after a coughing fit, but may appear relatively well between episodes. This stage can last 1-10 weeks.
- Convalescent stage. Coughing fits gradually improve in severity and frequency. This stage lasts 2-3 weeks.
Young infants may present with apnea or difficulty breathing. Vaccinated persons may present with milder disease.
Diagnosis
To diagnose pertussis, the CDC recommends obtaining a nasopharyngeal swab or aspirate from everyone with suspected pertussis. Pertussis is a nationally notifiable disease. Please notify the appropriate health department of all positive pertussis laboratory tests.
Prevention
The best way to prevent pertussis is to make sure patient vaccines are up to date. Pertussis vaccines are recommended for infants, children, teenagers, pregnant persons, and adults. The Advisory Committee on Immunization Practices (ACIP) recommends 5 doses of diphtheria, tetanus toxoid, and acellular pertussis (DTaP) vaccine at ages 2, 4, 6, and 15-18 months, and 4-6 years of age. Preteens and teens should receive one Tdap booster at 11-12 years of age. An additional dose of Tdap is recommended for all adults.
To prevent pertussis in young infants during the first few months of life, the CDC recommends all pregnant women to get a Tdap shot during the early part of the 3rd trimester of every pregnancy. All additional infant caregivers should be up to date with their pertussis vaccines.
For patients exposed to someone with pertussis, post-exposure prophylaxis with antibiotics may be needed to prevent illness and transmission to others.
Treatment
Antibiotic treatment is needed to reduce transmissibility, and to ameliorate symptoms if started early in the illness, for everyone with confirmed pertussis. The CDC also recommends starting empiric antibiotic treatment prior to test results for high risk individuals, including infants, anyone at high risk for severe or complicated disease, anyone in contact with someone else with severe disease, and anyone with more significant clinical symptoms. Treatment within the first 2 weeks of illness is most effective at reducing symptoms, and treatment after 3 weeks of illness is typically not recommended. However, initiation of antibiotic treatment within up to 6 weeks of illness should be considered in high-risk populations, such as infants younger than 1 year old and pregnant persons.
Macrolides (azithromycin, clarithroymcin, and erythromycin) are the preferred treatment for all age groups. For infants younger than 1 month old, azithromycin is the drug of choice for pertussis treatment and post-exposure prophylaxis. For patients older than 2 months old trimethoprim-sulfamethoxazole is a macrolide alternative. Recommended antibiotics and dosing are available in published guidance (Table 4) from the CDC.