As pertussis cases surge globally following a lull during the COVID-19 pandemic, the spotlight is turning to advancements in vaccines to combat this highly contagious respiratory disease. Reports indicate that pertussis cases in the European Economic Area in early 2024 outpaced all of 2023, raising alarms about the effectiveness of current vaccination strategies.
A Mother’s Harrowing Experience
Juliet Lautenbach, a civil servant from Canberra, Australia, recounts a grueling encounter with whooping cough that left her and her young daughter struggling to breathe. Despite both being vaccinated, they contracted the illness from a workplace exposure. Lautenbach recalls weeks of relentless coughing and her daughter’s severe symptoms, exacerbated by asthma, which required multiple emergency hospital visits.
“The vaccine may have saved her life, but I later learned that its effectiveness wanes over time,” she said.
Vaccination Efforts and Challenges
Pertussis vaccination, introduced in 1948 as part of the DTP combination vaccine, has drastically reduced fatalities, especially in children. Yet, current vaccines face growing limitations. Acellular vaccines, used in wealthier countries, are safer but less enduring in effectiveness compared to whole-cell vaccines still employed in many lower-income regions.
Dr. Camille Locht, research director at Inserm, notes that immunity from acellular vaccines diminishes faster, with protection dropping from 98% in the first year to as low as 42% after four years among adolescents. “Simply increasing booster shots isn’t a sustainable solution,” Locht warns.
Evolving Bacteria and a Changing Demographic
Strains of Bordetella pertussis are evolving, reducing vaccine effectiveness, while infection demographics shift. Previously seen mostly in unvaccinated infants, pertussis now disproportionately affects adolescents aged 10 to 19, whose immunity from childhood vaccines has waned.
Experts like Daniela Hozbor from Argentina’s La Plata National University emphasize the urgency of new solutions. “Preventing pertussis through vaccination is crucial,” she says, noting its rapid spread—up to 90% of susceptible individuals can contract it within an hour of exposure.
A Nasal Vaccine on the Horizon
Locht and his team are developing a third-generation vaccine, BPZE1, which uses live but weakened bacteria. Early trials show promise, with immunity lasting longer than current options and stimulating protection in the nasal mucosa, where the infection begins.
Kingston Mills, an immunology professor at Trinity College Dublin, underscores the potential of nasal vaccines. “They generate strong immune responses in the nasal cavity and lungs, where the infection occurs,” he says.
BPZE1 is slated for phase 3 clinical trials in 2025, with distribution potentially starting by 2027. Meanwhile, public health experts continue to stress the importance of booster shots and maternal vaccination to protect the most vulnerable.
As pertussis resurges, the race to deploy innovative vaccines offers hope for curbing the disease’s impact worldwide.
