Whooping cough (in doctor-speak pertussis, caused by the bacterium Bordetella pertussis) is akin to presidential elections, fashion, and the Winter Olympics.
All are cyclical.
Fashion tends to follow relatively long cycles-- after all, most of us had to recover from the trauma of the '80s before hairspray and leggings showed up again in our closets. Rest assured, traumatized and recovered people, Juno Mars' Superbowl half-time show last week confirmed that the '80s are back.
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| Whooping cough cycles every 3-5 years |
Weird, right?!
It's not really understood why this is; the cycling probably has to do with a combination of something called herd immunity, parts of the actual bacteria life cycle, and some evil wizardry of nature.
The last bad cycle of whooping cough in California was in 2010.
In California in 2010, there were more than 9,100 documented (laboratory-confirmed) cases of whooping cough. This was more cases than had EVER been reported in the vaccine era (The whooping cough vaccine came out in the 1940s). It can be assumed that there were many more thousand undocumented cases because many people with the disease don't actually get tested. Of these confirmed cases, 83% were in children under 18. That year, 10 California infants died of whooping cough. All infants were under three months of age, and most were under two months. Nine out of ten were Latinos. One of my wonderful residency classmates was involved in the care of one of those infants here in Sonoma County.
After that peak in 2010, California cases went down:
3,011 total cases in 2011
1,022 total cases in 2012
. . . but now cases seem to be increasing again:
2,372 cases in 2013.
For those Californians paying any attention, whooping cough may be coming baaaaack. Almost predictably so.
And the worst news of all? This week the California Department of Public Health announced the death of a 2 month old infant (the baby first got sick at 4 weeks of age). That's the first whooping cough infant death in California since the 2010 epidemic.
And that worries me-- and I'm thinking it should worry you as well.
What are the signs and symptoms of whooping cough?
You see, whooping cough is a pretty challenging diagnosis to make. In adults, whooping cough initially presents as a pretty mild respiratory illness, looking uncannily like the common cold.
Imagine this scenario: healthy adult comes to see her primary care provider with a few days of runny nose, low grade fever, and an intermittent cough. Astute clinician listens to her patient's lungs, checks her throat and her ears, feels reassured by no obvious bacterial infection (e.g. pneumonia, ear infection) and sends her on her way with recommendations about increasing fluids, considering zinc, vitamin C, honey and a few days of rest.
Welcome to my winter world.But for one or two of those cases, oops, I could easily miss it! What turns out to be whooping cough looks waaaaay too much like a cold for me to distinguish between the two. As you know, antibiotics are never ever indicated for the common cold, and it can be tough to decide whether to even consider testing someone for pertussis. And we certainly don't want to be handing out antibiotics willy nilly (definite fodder for future post).
After all, odds are overwhelming that the sniffling mess in front of me has a boring cold.
And now, armed with my overly-confident reassurance, that previously healthy adult has been released back out into the world to share her undiagnosed (and untreated) pertussis with her family and friends. Off she goes to cough and snot and whoop about and spread what can be a deadly disease, particularly for our most vulnerable little ones. Let's hope she doesn't have any young infants at home!
It's estimated that for every primary care of pertussis, there are 15 secondary cases. That's pretty contagious.
What happens next is this: after four to 21 days of a little cold, that apparently simple illness develops into a more intense illness with attacks (fits) of intense coughing. These happen most often at night, averaging about 15 fits per 24 hours. This stage (called the "paroxysmal stage") usually lasts a few weeks but can last up to 10 weeks. Ugh. This is why whooping cough is sometimes called the "100 day cough". Pretty annoying.
And this is when some (but not all) people whoop. If you want to hear what a whoop sounds like, check out this link.
Sounds pretty horrible, right? No one would miss that, right?
Here's the problem, though: plenty of adults and even infants with whooping cough don't actually ever whoop. Hmmm. . . Kiddos (i.e. ages 6-10) tend to be the whoopers, but not always them either. Goodness. And the little ones? Infants can present more subtly with poor feeding, periods of not breathing (aka apnea), and low heart rate.
The good news is that for kids and adults who get whooping cough, it's terribly annoying (no sleep, pee-your-pants annoying) without being life-threatening. The bad news is that infants can die.
In babies under one year old who get whooping cough, about half have to be hospitalized, and for those sick little guys and gals in the hospital, here are the stats:
- 23% (1 in 4) get pneumonia (lung infection)
- 1.6% (1-2 in 100) will have convulsions
- 67% (67 in 100) will have apnea (periods where they stop breathing)
- 0.4% (1 in 300) will get encephalopathy (disease of the brain)
- 1.6% (1-2 in 100) will die
Not good.
Whooping cough vaccination
In addition to the supremely important old school rules that you should ALWAYS follow when you are sick (you know, mom's rules: wash your hands, cover your cough, don't share utensils, don't go to work), the best way we know to prevent the spread of whooping cough is through vaccination.
There are two vaccines on the market: DTaP for infants and young children, Tdap for older children (over 7 years), adolescents, and adults. These are both combination vaccines: the "D" stands for diphtheria, the "T" for tetanus, and the "P" for pertussis. I've been asked a few times by parents who want to vaccinate only against pertussis; there is no way to get a vaccine with pertussis alone--anywhere in the world. It's not available.
The official CDC recommendation is for infants to be vaccinated with four total doses of DTaP at two, four, six, and 12-15 months. Vaccine efficacy after three doses of DTaP is between 80-95%; unfortunately there is no good data about how much immunity a baby gets after a single shot. There is also a recommended "kindergarten booster" of DTaP at age four to six years.
A study from the 2010 California outbreak showed that of pertussis cases in seven to 10-year-olds, unvaccinated kids, or kids with less than 5 DTaPs were almost nine times as likely to get pertussis than kids who were up to date on their shots.
You may have noticed that the babies who died in the California epidemic of 2010 (and the recent death in 2013) were almost all younger than the lower age limit for the first DTaP. They were too young to be vaccinated, but their family members weren't! It is assumed that those babies were exposed to pertussis by children or adults in their households that were either un- or under-vaccinated. There greatest risk was their loved ones.
This brings up the topic of Tdap, a vaccine licensed in 2005 for adults and children 11 and up.
The Tdap vaccine has been in the news a lot the last few years:
- a recent law in California requires all 7th graders to have a Tdap booster
- there are new CDC recommendations that all pregnant women get a Tdap in the third trimester, regardless of when the last time they vaccinated, and
- a new official recommendation in 2012 from ACIP that even adults over age 65 get vaccinated.
While 68% of teens have received their Tdap (brave teenagers!), estimates show that only 8% of adults are up to date on their Tdap vaccine. That's pretty pathetic!
The truth about vaccines
True true, vaccines are not perfect. Patients have the right to be skeptical about recommendations offered to them and to ask questions. It can be really challenging to find reliable answers to those questions, even for providers (like myself) who pride ourselves on being evidence-based and transparent.
Immunizations have side effects-- most of which are not serious--but rare serious effects do occur. God forbid one of those rare things happens to you or someone you love. I hope not! It is also true that no vaccine is 100% protective, and that's a bummer. So if your second cousin's aunt's brother tells you he was vaccinated and still got sick, it's probably true.
It's my daily reality that the medicine I practice is imperfect, but I believe strongly that the information we have for the safety and efficacy of most modern-day vaccines is based on robust scientific research, and we are a healthier human race because these vaccines exist.
If you have specific questions about vaccinations, their risks and/or your children's please please talk to your primary care provider. He/she should be a resource to you. Always.
And please consider getting yourself and your family up to date on their DTaP and/or Tdap vaccines. I know that there are LOTS and lots of reasons not to do it: you don't have time, you hate needles, you are scared of vaccine side effects, it seems like too many shots, it just doesn't seem worth it, you're lazy, you don't actually know who your primary care provider is, you have questions, you just don't want to. . .
Here's the bottom line, are any of these excuses worth a baby's life?
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Additional references:
http://www.cdc.gov/pertussis/images/pertussis-graph-2013-lg.gif
http://www.cdph.ca.gov/HealthInfo/discond/Documents/Pertussis%20report%202-4-2014.pdf
http://www.sciencebasedmedicine.org/pertussis-epidemic-2010/
Great lecture specifically for physicians: http://www.cdc.gov/vaccines/ed/pertussis/default.htm
http://www.immunize.org/askexperts/experts_diph.asp
http://www.cdc.gov/pertussis/about/complications.html
