Humboldt County May See an Official Outbreak of Whooping Cough (Pertussis)

Infant hospitalized with Whooping Cough [Photo from the Centers for Disease Control and Prevention website]

Hava Phillips, the Director of Humboldt County’s Communicable Diseases Program, explained that the Pertussis vaccine’s efficacy begins to drop after three to five years in kids. She said it appears that because of this waning trend in the vaccine, Whooping Cough “outbreaks” make regular returns to communities as the group’s immunity begins to “wear off.”

Periodic outbreaks of Whooping Cough appear to occur because the Pertussis vaccine wears off quickly in a percentage of the population. However, the Center for Disease Control website says that the pattern of Pertussis outbreaks is not fully understood.

When Phillips was asked if it possible that an outbreak may occur in the fall, she answered,

It is not an unreasonable assumption. What we know right now is we have had 3 cases diagnosed in the county in the last couple of months. And we also know that is has been between three and five years since we last had an outbreak in Humboldt County. So there is evidence that the bacteria is in the community. There for it is reason to think the immunity in the community [is lower.] But we do not know definitively that it is an outbreak.

Pertussis, also called Whooping Cough, results from a bacteria, Bordetella pertussis, which inflames the major airways with its mildly toxic “excretions.” As the bacteria count builds up, more toxins are delivered, the airways become inflamed and robbed of mucous causing the infected person to cough violently.

About 5-10 days after exposure, a person who has contracted Pertussis gets a clear, runny nose and mildly scratchy throat without much associated fever. The cough develops gradually.  At first it is mild, but after a few weeks, it can become quite serious.  Pertussis gets called “the 100 day cough” because the coughing can last for months. In adults, the cough is generally not deadly but it can be severe enough to break ribs in the elderly or make people vomit.  Children sometimes cough so hard their eyes blacken from broken blood vessels.

More dangerously, Whooping Cough can easily kill babies. It kills about a half a percent of the babies under 4 months old who contract it in the United States. Their airways are so small that the swelling leaves them vulnerable to asphyxiation during the violent coughing. They simply cannot get an in-breath. In 2014, 530 infants got Pertussis in California, and 3 of them died. In other words, 1 in 177 infants who contracted Pertussis that year did not survive. Among babies who do live, the bacteria sometimes causes long term complications with their immune systems and brain function.

Humboldt County reported no cases of Pertussis in 2018, 2017, and only 1 in 2016. However 2015 saw 56 cases of Whooping Cough, and in 2014 there were 148.

There is some concern that a new outbreak may be about to occur at least locally. On July 11th, the Public Health announced 3 confirmed cases of Pertussis had been confirmed since May. The very next day, a second press release informed the public that one person with the illness is a teenager whose diseased investigation revealed that patient had 40 known contacts since becoming contagious.  Those people are being contacted the press release said.

These are the first Pertussis cases in Humboldt since 2016. Each case is being formally investigated by the Communicable Disease Program of Humboldt County’s Public Health Branch as outlined by the Center for Disease Control.

Phillips said the disease investigation will inform the Communicable Disease staff whether this is an outbreak will occur. That information will help the Public Health Branch understand what the community needs to prepare for. Outbreaks climb, peak and decline over a 2 to 4 year period.

The Department is actively investigating each of the three confirmed cases. During an investigation of Pertussis, officials confirm through testing that the illness is, in fact, Whooping Cough. Once the illness is confirmed, they determine who each person was in contact with during the course of the illness, and work to speak to with those people to inform them they may have been exposed and to learn if they have contracted the bacteria. The investigation may proceed to their contacts if they have developed Pertussis.

Phillip said an outbreak is declared if certain thresholds or criteria are present. Factors include the concentration of the cases, the number of cases, and the connection between cases according to Phillips. She would not disclose which communities the 3 currently ill people live in, but she said the cases are dispersed and not concentrated. The investigation will determine if the ill people have an association or were in contact with one another.

Phillips said Humboldt County’s Public Health Branch will continue to inform the public when new cases are confirmed and whether an outbreak has begun.

Pertussis is described as an “highly communicable airborne illness,” but Phillips explained that immunized individuals are less likely to develop Whooping Cough and that closer contact with an infected person is more predictive of someone getting ill than simply being in a public space with an infected person. She re-emphasized that even if people are behind in their booster updates, those who have had the Pertussis vaccine will probably get a much less severe case of the illness than those who are not immunized at all and that it will not last nearly as long. People who contract Whooping Cough appear to have life long immunity according to literature at the CDC’s website.

In September of 2018, the Atlanta Journal-Constitution reported on Pertussis cycles in an article titled Why is Pertussis Making a Comeback? It explained that in the 1990’s, the way the vaccine is prepared changed to reduce associated side effects such as pain at the injection site and more significantly a potential for febrile convulsions caused by a sudden change in body temperature. The new vaccine has fewer side effects, but it also decreases in effectiveness over a shorter time and in a larger percentage of people.

Because Pertussis outbreaks do occur, and because the immunizing effects of the vaccine decrease over time in a significant percentage of people who receive it, Phillips said public health officials emphasize the importance of parents keeping up with the booster schedule for those who do choose to use immunizations. Babies are recommended to be immunized at 2,4 and 6 months with another booster between 15 to 18 months and again when children begin school between 4 and 6 years of age and at adolescence around 11 or 12 years old. Adults generally receive their booster for Whooping Cough in combination with their tetanus shots.

Phillips, and all the literature, emphasize that pregnant women should be immunized in the third trimester of every pregnancy because the immunity transfers to the baby and provides protection until the boosters begin.

Pertussis vaccines are available through the Public Health Department and most pharmacies. It is covered by most health insurance policies or it is $60. It generally takes 2 weeks to become effective. People who believe they have been exposed to a person with Pertussis should see their doctor. Antibiotics can shorten the course of the illness especially if taken early after exposure.

Earlier Chapters:

• Three Cases of Pertussis Confirmed in Humboldt County released June 11
• Eureka Teen Tests Positive for Pertussis released July 12th