A spike in pertussis, a contagious disease commonly known as whooping cough, has swept through Alaska, the state Department of Health reported.
Through the end of July, 131 pertussis cases had been reported in Alaska this year, according to an alert issued by the department’s Division of Public Health epidemiology section.
That compares to 26 cases reported last year, only two cases in 2022 and just one in 2021, according to the epidemiology section’s public health alert.
Of this year’s pertussis cases, 91 were reported in June and July, the epidemiology section said. Most were in the Southcentral region, the most populated part of Alaska.
Babies are most vulnerable to pertussis, the epidemiology section said in its alert. About a third of infected infants need to be hospitalized, and many can develop pneumonia, seizures and other complications, the bulletin said. Some can die from the disease, with most of the deaths reported among babies younger than 3 months old, the alert said. Across the U.S. from 2010 to 2020, up to 20 infants died annually from pertussis, the alert said.
In Southeast Alaska, where seven cases have been reported since June, health officials issued recommendations for treatment and prevention of the highly contagious disease.
People with symptoms like persistent coughing should seek medical care immediately, and those who are possibly sick or who have been exposed to pertussis patients should wash their hands frequently, wear masks and otherwise practice good hygiene, the SouthEast Alaska Regional Health Consortium said in a statement.
A key prevention tool is vaccination, and both adults and children should be up to date on those vaccinations, the consortium statement said.
“We want to ensure that the public is fully informed about the risks associated with pertussis and the steps they can take to protect themselves and their loved ones,” Dr. Cate Burley, the consortium’s chief medical officer, said in the statement. “Early diagnosis and vaccination are key to preventing the spread of this illness.”
Pertussis vaccines are typically bundled with vaccines for tetanus and diphtheria, into packages called DTaP or Tdap. The combined vaccine is recommended by the U.S. Centers for Disease Control and Prevention at regular intervals for both children and adults. For children, the CDC-recommended schedule is four doses by 15 months, followed by a dose at about age 11 or 12. For adults, the CDC-recommended schedule is a dose every 10 years, as well as during pregnancies or in certain other special circumstances.
The epidemiology section’s public health alert also stressed the importance of vaccination.
“The best way to prevent pertussis is to get vaccinated. Pertussis remains one of the leading causes of vaccine-preventable deaths worldwide, despite overall high vaccination coverage. Most pertussis deaths occur in young babies who are either unvaccinated or incompletely vaccinated,” it said.
Alaska’s increase in pertussis comes as cases are rising nationally, reversing a sharp decline in pertussis cases experienced during the COVID-19 pandemic, the CDC reported.
Health precautions used to prevent the spread of COVID-19 likely prevented the spread of pertussis, the CDC said. Reported cases now are at a more “typical” level and close to the level reported in 2019, the CDC said.
The years with almost no Alaska pertussis cases — 2021 and 2022 — overlapped with the COVID-19 pandemic and the precautions imposed to prevent the spread of that disease.
Aside from those pandemic years, pertussis in Alaska has come in waves, generally in cycles of three to five years, state health officials said.
There have been years with high numbers. In 2012, there were 356 cases reported and in 2013, the total was 308, according to the epidemiology section’s 2013 annual infectious disease report. There are also years with much lower numbers, aside from the recent pandemic years. In 2011, for example, only 24 cases were reported, according to state health officials.
The wave pattern exists for multiple reasons, Dr. Joe McLaughlin, chief of the state’s epidemiology section, said by email.
Immunity to the disease, whether acquired through vaccination or infection, wanes over time, he said. There can be incomplete vaccine coverage in the population, he said. Additionally, the bacterium that causes the disease, Bordetella pertussis, can evolve into strains that partially evade people’s immunity, he said. And changes in population makeup – with new babies born and older children or adults losing their immunity over time, can trigger periodic epidemics, he said.
A different wave pattern, spread out over the past 12 months, is shown in Alaska for other contagious respiratory diseases. For COVID-19, influenza and respiratory syncytial virus, combined case numbers were higher in late fall and midwinter but lower in late spring and early summer, according to the Alaska Division of Public Health.
