There is currently
an increased rate of pertussis (whooping cough) in our area. We wanted to give
our patients some current information on this disease and how it is being
treated, especially since it gets reported to the Board of Health and may
require seemingly healthy people to take antibiotics to prevent disease.
Pertussis (meaning intense cough) is caused by a bacteria. We all get immunized as children but the vaccine is about 80-90% protective and our ability to have immunity to the bacteria wanes by the time we are in our teens. The vaccine is most important (the "P" in DpaT) in protecting infants in the first year of life as they can get very ill if they contract the disease. Despite the limitations on the efficacy of the vaccine, this has seemed to work well with only a handful of cases in our state each year. It is not clear why, but we now have an increase in cases and because the bacteria are 90% effective in spreading to those who are susceptible, it can spread through populations quite rapidly. Adding to this is the fact that some people have very mild symptoms and can spread it unknowingly to family and friends.
Pertussis is transmitted by droplets released during intense coughing. The incubation after an exposure to contracting the disease has a mean of 6 days and a range of 6-21 days. The first symptoms (catarrhal) are runny nose, mild cough and possibly a low grade fever and they can last 1-2 weeks. The second stage (paroxysmal) involves coughing that increases in severity and frequency often leading to vomiting, lasting 2-4 weeks. In the third stage (convalescent), the coughing and vomiting decrease in frequency and severity but still exist. There is no lasting damage from the bacteria despite the intensity of the cough that it produces.
We will be considering pertussis in your child if we hear there has been 1) An exposure to pertussis within the past 21 days. 2) A cough for more than two weeks; especially one that involves vomiting after coughing or has the classic whoop.
The best way to break the cycle of contagion if your child meets these criteria for possible pertussis is to do a culture and PCR (this is done via a small swab that is placed in each nostril and then put into culture media; the PCR is essentially a quick test but it can miss some so the culture is used as a back up), place the child on Zithromax (or erythromycin; other antibiotics are not effective against pertussis) and place household contacts also on Zithromax. The adults in the family will be asked to call their doctors for the medication but we are happy to talk to the internists about the pertussis outbreak as they may not yet be aware of the increased incidence. The medication is taken for FIVE days and there can be no school, work, daycare, or casual contact for anyone who is considered to have active disease or their close contacts. We understand the hardship this places on your family and will not diagnose pertussis without a lot of thoughtful consideration. Your case will be called into the Board of Health and they will determine which people you may have infected and whether they too require antibiotics. The general exposure rule for non-household contacts is they have had to have been within three feet for 10 minutes, in the same confined space for greater than one hour or to have direct contact with the secretions of someone with pertussis.
Overall, most people will recover uneventfully from pertussis. The real concern is for infants in the first year of life and those whose immunity is compromised. If your child is not up to date on their immunizations we urge you to do this and if they have had an exposure we urge it even more strongly as it may help even during the incubation period. In an infant, pertussis does not always present with cough; it can present with periods of apnea (not breathing).
The DPaT is given 5 times in the first 5 years of life. It is given as Tdap after age 10 (if you have had a tetanus vaccine greater than 2 years ago) and should be obtained every 10 years.
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