As you have probably heard, the US is in the midst of a widespread pertussis outbreak.
And closer to home, a school in Floyd County, Virginia has closed for a week because of an outbreak. (http://www.roanoke.com/news/breaking/wb/282367Pertussis ). Pertussis is the short name for Bordetella pertussis, the bacterium that causes whooping cough. As you have probably also heard, April is Autism awareness month. I have been planning to write a post on autism ever since a reader wrote to me about several bad experiences her son, who has high-functioning autism, has had when visiting medical offices. And while I still plan to write the post on how we view and treat individuals with disabilities, especially autism, I feel I must address this pertussis issue first.
Nonetheless, there is a relationship between the low rate of pertussis immunization in certain populations, and some myths about autism.
Pertussis (whooping cough) is a disease that is preventable with immunization. The vaccine available to prevent pertussis has gotten increasingly safe and effective over the last few decades. When I was first in practice, the vaccine was derived from the whole cells of the bacteria, and as such, had a fairly high rate of complications, such as high fever and pain and swelling. Because children receiving the pertussis vaccine were at the age when children are nauturally vulnerable to having seizures with high fevers (febrile seizures), the vaccine got a bad name for itself, in that it was thought by some people to cause seizures or epilepsy. This has been proven NOT to be the case. More recently, the vaccine uses more elegant means of isolating the appropriate components of the bacterium that are able to initiate an immune response, but have a much lower incidence of general side effects, yet it is highly effective in preventing disease. AND THERE IS NO EVIDENCE THAT IT CAN CAUSE AUTISM.
Infants receive their first SERIES of pertussis vaccinations at 2, 4, 6 and 15-18 months, in the same shot with the vaccinations for diptheria (D) and tetanus (T). That shot is called DTaP. "aP" stands for "acellular pertussis" and tells you it is the new form of the vaccine. They get a booster at 4-6 years. At 11-12 years they should have a booster with a shot known as Tdap, which has slightly different doses of the diptheria and pertussis components.
Resistance to infection improves with each additional shot and may remain incomplete until the entire initial series has been administered at 15-18 months.
Therefore children are at most risk to contract this disease if they are unimmunized (through parental choice or under two months of age) or they are partially immunized (before they have had their 4th DTaP shot). The disease itself is most severe in the youngest infants, who may require hospitalization, potentially mechanical ventilation (having a breathing tube in their throats and being attached to a machine to breathe for them) in the pediatric intensive care unit, and yes, some of them may die--this is usually from hypoxia (low oxygen levels in the blood) and/or apnea.
How do young infants contract this disease? A letter written by the American Academy of Pediatrics among other medical organizations, to health care providers states:
Studies have indicated that 75%-83% of infant pertussis cases with a known source exposure were caused by an infected household member. Parents and siblings are the most common source, with 55% of cases in infants linked to an infected parent.
Therefore, it has become standard practice in many OB practices and delivery services to offer Tdap to women with newborns.
It is strongly suggested that everyone be immunized against pertussis if they are going to be around a newborn, and its been at least 10 years since their last pertussis vaccine. Adults should obtain one dose of Tdap if they have never had one, especially if over the age of 65.
I have seen many, many children with pertussis over my years practicing as a pediatric intensivist.
While older children and adults may present with a classic staccato cough followed by a "whoop" when they finally are able to take a breath, very small infants may present with a non-specific respiratory infection. Doctors can be helped to make the diagnosis by looking at the Complete Blood Count (CBC) in which the white blood cells WBCs--the cells that fight infection) are very high (in some cases I have seen as high as 70,000, where normal can be up to about 15,000) with a very high percentage of lymphocytes (the which cells we typically associate with viruses). In addition, the chest XRays are often characteristic, showing a "shaggy" appearance of the peri-hilar area (the area on either side of the middle of the chest, but not extending out too far). However, most children do not show all the "classic signs" and the youngest children may show only evidence that they are ill with something affecting how they breathe. In most cases, the "clue" that this might be pertussis is that there is at least one adult in the family who has had a chronic cough, usually without fever, and may not seem all that sick from it.
The bottom line here after all this ranting, is that you should get your kids immunized if they have not been already, and you should encourage the adults with whom they associate frequently to get immunized. You cannot catch the disease from the immunization, it does NOT cause seizures, epilepsy or autism.
I have seen infants die of this disease (thankfully not here in Roanoke), and I am always extremely sad to think that such deaths could have been prevented by the simple act of immunization.
As usual, I welcome your comments and concerns, your thoughts, questions and observations.