A wave of whooping cough infections The pandemic continues to worsen across the country, data from the Centers for Disease Control and Prevention suggest, with weekly reported cases accelerating to the highest levels seen in the United States in years.
The CDC now says at least 259 cases of whooping cough were reported during the first week of August, up from 215 cases per week in late June.
Pennsylvania It has reported 1,489 cases so far this year, the most of any state. New York has reported the next-largest total of cases, with 1,266 infections.
The surge comes as CDC officials have been warning for months about a return to pre-pandemic trends for the disease. Whooping cough is caused by the bacteria Bordetella pertussis, which had plummeted to historic lows during the COVID-19 pandemic, likely due to more people wearing masks and staying home from school and the office at the time.
So far this year, health departments have reported a total of more than 10,000 cases of whooping cough. As of mid-June, this year's total cases were more than triple what they were compared to the same period last year.
Reported cases this year are also now higher than just before the pandemic, which had reached around 8,000 cases by early August 2019.
Why are whooping cough cases accelerating?
Many diseases that are transmitted from person to person through the air, such as whooping cough, saw their infection rates drop during the COVID-19 pandemic.
“Mitigation measures used during the pandemic (e.g., mask wearing, distance learning) have likely reduced transmission of pertussis,” the CDC said in July.
That interrupted what had been signs that whooping cough rates were starting to rise again, after falling from an earlier peak in 2012.
“The increase in pertussis that we're seeing continued through the onset of the COVID-19 pandemic in 2020, after which we saw the dramatic decline in reported pertussis, which was similar to trends for other notifiable diseases nationally,” said CDC epidemiologist Tami Skoff at an April event hosted by the National Foundation for Infectious Diseases.
Skoff said several factors were behind the gradual rise in whooping cough cases before the pandemic, including improved rates of diagnosis and reporting of infections.
Another reason may be traced to the shift in the 1990s to a safer type of vaccine, known as “acellular” shots, whose protection wanes over time.
“We think one of the driving factors and one of the biggest contributors is the waning protection of acellular pertussis vaccines,” Skoff said.
Skoff said CDC vaccine experts do not plan to revisit the issue of whooping cough vaccines after deciding not to recommend booster doses for the 2012 surge. But new vaccines could lead to changes in the agency's guidelines, she said.
“There are vaccines in development. We hope that in the coming years we will have vaccines available with a longer duration of protection,” he said.
What are the symptoms of whooping cough?
Doctors typically divide whooping cough into at least three stages, beginning with the initial appearance of common cold-like symptoms, such as cough and runny nose. Symptoms typically appear about a week after the patient has first been exposed to another contagious person.
The cough worsens for up to six more weeks, often with the characteristic “wheezing” sound, which occurs when patients have difficulty breathing after bursts of rapid coughing to try to expel mucus built up in the body's airways.
This can cause the skin to turn blue or purple, due to lack of oxygen in the body, and vomiting afterwards.
Symptoms may vary depending on the age of the patient. Infants are at greatest risk for severe whooping cough and have the highest rates of hospitalization.
While vaccines and better treatments have prevented the thousands of childhood deaths that whooping cough once caused each year in the early 20th century, severe cases can lead to complications such as pneumonia and neurological problems, especially in infants.
How is whooping cough treated?
Antibiotics can be effective in reducing the severity of whooping cough, especially if started early in the course of infection, according to the CDC. They can also be given to close contacts at risk for whooping cough cases to prevent them from getting sick.
Doctors can test patients with symptoms by inserting a swab deep into the nose. Those tests are most accurate when done within the first three weeks of the cough, the CDC says.
“In the context of waning immunity, we're seeing more and more cases in older people, and I often hear doctors say that we don't think about whooping cough in older people or that they come to care much later when some of the diagnostic tests aren't accurate,” Skoff said.
Testing is not always necessary to start antibiotic treatment in patients, especially if they are at risk of severe illness. People who have been diagnosed with whooping cough may be given antibiotics such as azithromycin for up to five days to treat infections, although this does not guarantee that people will experience faster relief from their symptoms.
“Antibiotics are intended to prevent transmission of pertussis to others and do not shorten the course of the disease or improve symptoms,” the doctors said in an article published by the American Academy of Family Physicians, citing a review of 13 trials.
