The United States has reported over 32,000 cases of whooping cough, or pertussis, this year—nearly five times the 6,500 cases recorded during the same period in 2023, the Washington Post reports.
This sharp increase has raised alarm among health experts, marking the highest number of cases in a decade.
Experts attribute the surge to declining vaccination rates and reduced immunity resulting from pandemic-related disruptions. Vaccinations against pertussis, such as the DTaP vaccine for young children and Tdap for teenagers and adults, saw a significant decline during the height of the COVID-19 pandemic when routine healthcare visits were interrupted.
Although social distancing and mask-wearing temporarily kept pertussis cases low, these measures also delayed immunity-building in the population. Many children who missed their scheduled DTaP shots in 2020 may have never received them, leaving a gap in protection.
Pertussis, caused by the bacterium Bordetella pertussis, is highly contagious and spreads through airborne droplets. Infants under one year of age are particularly vulnerable, with their immature immune systems putting them at the highest risk for severe complications.
The Centers for Disease Control and Prevention (CDC) reports that the DTaP vaccine provides 98% protection within a year of the final dose in children but wanes over time, with about 71% of recipients still protected after five years.
States such as California, Illinois, New York, and Ohio have reported the highest rates of pertussis, leading to calls for urgent vaccination efforts. In response, the Department of Health and Human Services launched the “Let’s Get Real” campaign to raise awareness about childhood vaccines and provide educational tools for pediatricians.
“Increasing vaccination rates and public awareness is critical to protecting vulnerable populations,” said Scott Roberts, an infectious disease specialist at Yale School of Medicine.
Diagnosing pertussis can be challenging, as its early symptoms mimic those of a common cold. Many cases go unreported, contributing to its spread. Testing involves expensive procedures, such as PCR evaluations or antibody checks, which may not be widely accessible.
Treatment with antibiotics like azithromycin can reduce the severity of the illness if administered early. However, delayed diagnoses often lead to prolonged suffering, with some patients experiencing months of persistent coughing.
There are concerns that the bacterium causing pertussis may be evolving to evade existing vaccines, which could complicate prevention efforts further.
“Waning immunity is part of the picture, but the vaccine may also be less effective because the bacterium is evolving to outsmart it,” said Anita Patel, a pediatric critical care physician.
“The rise in cases is striking,” Roberts said. “Without immediate action, we risk seeing even greater numbers in the years to come.”
