Amid Pertussis Surge, Appropriate Bordetella Testing Options Are Essential For Better Outcomes

By Ed Janoszewski

Clinical labs may need a targeted or panel test depending on the situation

They call it the hundred-day cough. After years of declining infection rates, pertussis ­— better known as whooping cough — is surging. Last spring, health officials in Europe sounded the alarm as tens of thousands of cases were detected, with the worst infections and mortality rates seen in infants. By summer, public health agencies warned about similar spikes in Latin American countries including Brazil, Peru, and Mexico. In the US late last year, the Centers for Disease Control and Prevention (CDC) issued an alert as pertussis levels soared to six times those seen at the same time the year before. Year-end reports documented about 7,000 cases in the US in 2023, and more than 35,000 cases in 2024.

There’s a perfect storm of factors contributing to this trend. Like most respiratory infections, pertussis spread less during the COVID-19 pandemic as people adopted precautions such as masking, keeping socially distant, and staying home when sick. However, like its respiratory counterparts, pertussis has rebounded as people reverted to their normal behavior.

Additionally, while pertussis vaccination is widely recommended as the best way to prevent illness, broader fears and resistance to vaccines have reduced compliance. The pandemic also disrupted routine vaccination schedules, leaving some people — especially children — with less protection than they might otherwise have had. For those vaccinated, immunity can wane over time, leading to increased susceptibility to whooping cough. Currently, the CDC does not have a recommendation for pertussis vaccine booster doses to restore immune protection in older adults.

Furthermore, doctors are aware of whooping cough’s rise in cases and have increased their testing for the underlying main pathogen, Bordetella pertussis. More frequent testing is making it possible to detect and report cases that might have been missed otherwise.

Bordetella testing

Bordetella testing is essential for optimal patient outcomes with this highly transmissible infection. Identifying pertussis cases can help mitigate local outbreaks, for example, by keeping sick children home from school when they are most contagious, and it also allows physicians to select the most appropriate antibiotics for faster treatment. A history of pertussis in children can also contribute to a potential risk of developing asthma, making it important for patients to know whether their illness was pertussis or some other pathogen.

For clinical laboratory teams, choosing the right Bordetella test can be a challenge. Accuracy is essential; in addition to needing reliable information for patient care, labs are also required to report Bordetella cases to the CDC and other public health departments. Another crucial factor is timing. Acute pertussis presents similarly to common respiratory infections, yet as the disease progresses, the telltale cough differentiates from other respiratory patients. For that reason, using broad respiratory panels is often not in line with diagnostic stewardship initiatives. Instead, a targeted test for Bordetella alone or a flexible panel that allows for the choice of specific targets should be used to confirm the diagnosis once patients have developed symptoms unique to whooping cough. There are some cases — for example, when extremely ill pediatric patients with symptoms of respiratory illness are admitted to a hospital — where using a broad testing panel is appropriate.

The Diasorin Solution

At Diasorin, we are proud to be the only test provider that offers both a targeted Bordetella test and a flexible respiratory panel that includes Bordetella, offering laboratories and their physicians the appropriate Bordetella testing solution based on the clinical situation.

The Simplexa® Bordetella Direct test is a well-established real-time qualitative PCR assay that allows users to detect and differentiate Bordetella pertussis and Bordetella parapertussis using the widely installed LIAISON® MDX instrument. An excellent option for an outbreak scenario where pertussis is known to be spreading in a community, this targeted diagnostic assay is ideal for confirmation testing, which can help physicians choose the most appropriate antibiotics to reduce severity and shorten the duration of illness. This is especially true in cases where healthcare professionals delay treatment until they’re certain whether the pathogen is viral or bacterial.

When clinical lab teams desire flexibility in testing, they can deploy the recently commercialized LIAISON PLEX® Respiratory Flex Assay, which includes Bordetella pertussis and Bordetella parapertussis, as well as Bordetella holmesii, in addition to several viruses and bacteria that are common culprits in respiratory infections. With the Flex testing model, users can report results for all these pathogens or choose a subset that’s most appropriate for each case, paying only for the results reported.

Given the significant rise in pertussis cases, many laboratories that have not had to test for this pathogen need to consider adding it to their test menu. Labs that already have either the LIAISON® MDX instrument or the LIAISON PLEX® System can advocate to stem the spread of this surging pathogen by easily incorporating Bordetella testing to ensure reliable detection and more customized care for each patient.

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