By Asuka Koda, CNN
(CNN) — For the second year in a row, the US has surpassed 25,000 whooping cough cases — another sign of the risks of falling vaccination levels.
Often called the “100-day cough,” whooping cough or pertussis begins with cold-like symptoms such as runny nose, fever or cough that can progress to coughing fits that last weeks or months, according to the US Centers for Disease Control and Prevention. A “whoop” sound when coughing may appear in the second phase of illness.
The infection can lead to severe illness or death, especially in young children: About 1 in 3 babies younger than 1 who have whooping cough requires care in a hospital. Still, experts believe that much of the disease goes unrecognized and unreported, the CDC says.
The CDC reported nearly 28,000 cases this year, an elevated level after a peak last year, when the agency reported 35,493 cases. One year earlier, in 2023, there were only 7,063 cases reported.
The last time numbers were similarly high was 2014, when there were 32,971 cases.
Thirteen deaths from pertussis have been reported in the US this year, according to the Pan American Health Organization, most of them children under 1 year old.
The rise in whooping cough is not unique to the US, according to the Pan American Health Organization, which serves as the World Health Organization’s office for the Americas region. Last year, 977,000 cases of pertussis were reported to WHO, a five-fold increase over 2023.
Dr. Scott Roberts, associate medical director for infection prevention at the Yale School of Medicine, believes the US rise is driven by falling vaccination rates along with a loss of population-wide immunity during the Covid-19 pandemic, among other factors.
“I worry vaccine hesitancy is playing a role. This is a vaccine-preventable illness, and any decline in vaccine rates will lead to increases in pertussis,” he said.
Vaccines prevent whooping cough
The CDC recommends routine diphtheria, tetanus and pertussis (DTaP) vaccination for all infants and children under 7 through a five-dose series beginning at 2 months of age. Children who get all five doses of the DTaP vaccine on schedule are 98% protected from illness within the year after the last dose. About 70% of children are fully protected five years after getting the last dose, according to the CDC.
Adults and adolescents are urged to get a booster Td or Tdap vaccination every 10 years, starting at the age of 11 or 12, to maintain protection. Roberts recommends choosing the version that protects against pertussis — Tdap — when possible.
“Last year, we had a lot of college outbreaks. What happens is, a lot of people get their childhood vaccine series, and then they don’t get the booster series,” Roberts said. He noted that many of those outbreaks were driven by students who had lost their immunity and were living in group settings where the disease spreads easily.
A return to shared indoor spaces after the pandemic may have also contributed to the increase, he said.
There had been limited exposure to routine pathogens because of Covid-19 mitigation measures, he said, but now “a greater proportion of people are getting exposed to the pathogen, all at the same time. I wonder if there is some degree of loss of population immunity that we’re still recovering from, and maybe things will [stabilize] over the next few years.”
Additionally, the PAHO Read more