By: Jiayan Liu
Image courtesy of Science Museum Group Collection UK
The Washoe County Health District has confirmed four cases of pertussis (whooping cough) at Bishop Manogue High School in Reno, Nevada on October 22, 2019 . The school and health district jointly decided to close the school and cancel all school activities until November 4 in order to reduce transmissions of disease and prevent additional cases from occurring among students and staff. A letter was sent out to parents or guardians of Bishop Manogue students to alert them of the exposure to whooping cough and highly recommend students to receive antibiotics even if they were healthy and to be vaccinated if they had not yet received the pertussis vaccine.
Pertussis is a highly contagious respiratory disease caused by bacterium Bordetella pertussis. It is known for uncontrollable, violent coughing that causes difficulty breathing and serious illness in all ages. Symptoms of pertussis usually start with cold-like symptoms, mild cough or fever, followed by rapid cough or vomiting appearing in the later stage. It is especially dangerous for babies under one year old since the rapid cough may lead to pauses in their breathing pattern. The best way to protect against pertussis is by getting vaccinated. The Centers for Disease Control and Prevention (CDC) recommends DTap (Diphtheria, Tetanus, and Pertussis) vaccine for children younger the age of seven and the Tdap vaccine for older children, teens and adults . The recommended antibiotic treatments of pertussis are macrolides erythromycin, clarithromycin and azithromycin for persons at least one month old. For infants younger than one month, azithromycin is preferred.
Outbreaks of pertussis are also ongoing in Kentucky, Michigan and Alberta Canada. Nine cases have been confirmed in a Kentucky high school since 2019 . Eight confirmed cases were reported in Ann Arbor Public Schools on October 17, 2019 . There have been 15 new cases confirmed in South Alberta in October, bringing the total number of confirmed cases to 49 across this area for 2019 . A new study suggested that waning potency of pertussis vaccines between doses is a significant contributor to recent whooping cough outbreaks . The researchers found that the risk of pertussis increased as more time passed since their last vaccine for fully vaccinated children. Under-vaccinated children, including who only received one vaccine or were behind schedule were almost twice as likely to develop pertussis compared to fully vaccinated children. More studies are needed to quantify the relative roles of vaccine waning and under-vaccination in pertussis outbreak. The researchers emphasized that vaccination is still encouraging without doubt and families and clinicians should continue vaccinating children according to the CDC’s recommended schedule.
A joint study between China and Australia discovered that a new strain of Bordetella pertussis has become resistant to antibiotic erythromycin and may also be resistant to the vaccine used in China . The researchers found that 98% of the new strain isolated were resistant to erythromycin, and it contains a mutation in one of the vaccine antigen genes, which can help the bacteria evade the two-component acellular vaccine prescribed in China. Erythromycin is also the main antibiotic for pertussis used in the US. Although this new strain has not been found in the US, the growing threat of it spreading should be taken seriously.
- Ousseny Zerbo, Joan Bartlett & Kristin Goddard, Bruce Fireman, Edwin Lewis, Nicola P. Klein (2019) Acellular Pertussis Vaccine Effectiveness Over Time. Pediatrics, e20183466 DOI: 10.1542/peds.2018-3466
- Zheng Xu, Zengguo Wang, Yang Luan, Yarong Li, Xiaoguai Liu, Xiaokang Peng, Sophie Octavia, Michael Payne & Ruiting Lan (2019) Genomic epidemiology of erythromycin-resistant Bordetella pertussis in China, Emerging Microbes & Infections, 8:1, 461-470, DOI: 10.1080/22221751.2019.1587315