The number of pertussis or whooping cough cases in the United States has risen by more than 300% since October 2023, according to a recent report from the Centers for Disease Control and Prevention (CDC).
The public health organization estimated more than 17,600 cases of whooping cough in the US as of Oct. 5. In comparison, there were only 3,962 cases reported in the same period a year ago. That marks a 340% increase.
Over a one-week period, whooping cough cases increased by 1,204 from 16,375 cases reported in the week ending Sept. 28, per the CDC.
The current share of infections echoes numbers seen pre-pandemic, which typically exceeded 10,000 yearly. Pertussis cases spiked in 2019 when health officials reported 18,600 infections.
That said, whooping cough cases had a significant decline during the COVID-19 pandemic, with only 2,100 cases reported in 2021.
Where Are Pertussis Cases Rising in the US
By region, the Middle Atlantic had the most number of whooping cough infections with 4,529 cases in the week ending Oct. 5. The East North Central region follows with 3,574, and then the Pacific with 2,951.
By state, Pennsylvania had the highest number of cumulative cases to data with 2,209. Other states with the highest whooping cough infections include:
- New York: 1,228
- Illinois: 1,153
- California: 1,123
- Wisconsin: 903
- Washington: 844
- Ohio: 814
- Texas: 676
- Oregon: 546
- Arizona: 491
Why Pertussis Cases Are Rising Again
It is not immediately clear why pertussis infections are rising again. Experts believe the decline seen during the pandemic is due to mask-wearing and social distancing protocols. Low vaccination rates in some populations are also attributed to the recent increase in pertussis infections.
Furthermore, senior medical analyst Dr. Marc Siegel said the immune system is now slower to respond, especially against viruses that "we haven't seen."
"They are increasing more now as our immune systems are exposed to viruses and bacteria we haven't seen and are slower to respond," he told Fox News Digital.
Approximately 160,000 children under age 5 worldwide die of pertussis each year, CDC data showed.
