Pertussis and transmission

[wallacesmum]

I know that mamakay has done a ton of research on this, and has put up some research on MDC, but I thought we should have a discussion of this topic here (if we haven't already).

[Momtezuma Tuatara]

Why not. I'm not sure where you want to start though...

for a start, it's a myth that the immune cannot pass on whooping cough...

[MinorityView]

Well, one of the obvious questions is...how is whooping cough transmitted in the first place?

Droplets in the air? Kisses? How much exposure does it take? One cough in your vicinity or a week of constant contact? Is there any data?

http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/pert-508.pdf


Adolescents and adults and children partially protected by the vaccine may become infected with B. pertussis but may have milder disease than infants and young children.

Reservoir
Pertussis is a human disease. No animal or insect source or vector is known to exist. Adolescents and adults are an important reservoir for B. pertussis and are often the source of infection for infants.
Transmission
Transmission most commonly occurs by the respiratory route through contact with respiratory droplets, or by contact with airborne droplets of respiratory secretions. Transmission occurs less frequently by contact with freshly contaminated articles of an infected person.


Pertussis is highly communicable, as evidenced by secondary attack rates of 80% among susceptible household contacts. Persons with pertussis are most infectious during the catarrhal period and the first 2 weeks after cough onset (i.e., approximately 21 days).

I'm not quite satisfied with this info. They go on to strongly recommend the vaccine to prevent transmission, but don't seem to have any evidence that the vaccine will do this. Unless i missed it.

[Trogdor]

When I asked the health department if getting the vaccine would prevent transmission they said "We don't know but it will protect your child". Of course this is the same health department that didn't know mumps was viral. *shrugs*

I also can't find any concrete evidence on the rate of people who are asymptomatic.

[MinorityView]

Asymptomatic is one problem. Misdiagnosed is an even bigger one.

[Spy]

I also can't find any concrete evidence on the rate of people who are asymptomatic.

I can't even think of a way to get any concrete evidence there. :D

[MinorityView]

Actually, our mutual friend ________, had come up with something based on evidence of immunity in the population. Apparently with blood tests or saliva tests or something like that, you can tell if someone has had pertussis within a certain number of years. According to this, everyone has it every few years. But many cases are misdiagnosed and some cases aren't spotted at all. Also according to our mutual friend, some 10% of cases are totally asymptomatic, based on the evidence of the above tests combined with the fact that the people involved said: "whooping cough?"

I'm one of those people. As far as I know I've never had whooping cough, nor has anyone else in my family. But I've never been tested for exposure, either, so I'm not a good test case.

[GreenGully]

I had a pertussis "scare" last year. It was scary only because I was so sick (unusual for me) and I am a single parent and the thought of being so ill for months to come was, well, scary. It was a chest infection (I haven't had one in more than 15 years) which responded slowly to AB's, vit C and OLE. (I have alpha one anti trypsin deficiency so am extra cautious with my lungs - I took ABs only after I continued to get worse on high doses of vit C and OLE). Anyway my GP who is pro vax was unsurprised when I mentioned my son is unvaxxed - she seemed to think asymptomatic case were common.

[Momtezuma Tuatara]

Then why on earth didn't she do a nasal pharyngeal swab, with PCR staining? it's all very well for them to nod sagely about unvaccinated children, as if that is the problem, but I had whooping cough four years ago, long after my children became adults. I know it was whooping cough, and the only reason I didn't go for a swab was because I had no interest in proving it. Whooping cough was quite happily swanning around the schools and district, and just no-one in the medical profession was prepared to open their mouths.

Which might have something to do with a Public Health Surveillance admission not long before that the vaccine we use only has a 33% "effective" immunisation. Under those circumstances, I suppose the best thing to do is shut up.

[GreenGully]

She did do a swab on me, but considering I was so ill at the time and getting worse even with the natural therapies I could access at the time (I am quite isolated here, though there is a GP close by) and the time delay in getting lab results back (over a week), I chose to take the ABs which could be delivered in hours. (If only natural therapies were as accessible). I suppose the threat of developing pneumonia and being hospitalised was too great (in my mind), as there woudl have been no one to care for my son. Ideally I would have consulted a naturopath and rested and ridden it out. There is no way I would have let her swab my son, he would have found it too traumatic. My swab came back negative.

[Momtezuma Tuatara]

Did she do a culture swab, or a PCR swab?

[GreenGully]

:lol I wouldn't have a clue, I was a bit out of it.

[cartersmom]

Aren't those swabs very innacurate if not done in a timely manner??? I thought once the cough sets in, the window of getting an accurate diagnosis is much smaller.

[wallacesmum]

It is very *ahem* interesting that she would nod sagely upon hearing that your son is unvaccinated. Since we are talking asymptomatic cases here, and the vaccine appears to work only in terms of lessening the symptoms, wouldn't it be Vaccinated people that would be more likely to have asymptomatic cases (based on the CDC science and logic)?

From the thread I mentioned on MDC:

http://iai.asm.org/cgi/content/abstract/68/12/7175
showing a lack of bacteriacidal activity by the vaccine - and vaccination seems to have had the opposite effect in two cases (although I haven't seen the full text)


Immunization did not result in improved bactericidal activity for any of the individuals, and in two cases immunization caused a statistically significant decrease in complement-mediated lysis.

This is also from MK on that thread:
http://www.journals.uchicago.edu/doi/full/10.1086/381204?cookieSet=1

which is about adenylate cyclase toxin (ACT) and how if it isn't in the vax (which it isn't in some cases) or if it doesn't work, then vaxed kids are MORE susceptible to this component in the wild virus.

And this:
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=529164

About the actual rates of protection. These relate to adults, so they are particularly relevant for transmission discussions.

[Momtezuma Tuatara]

Aren't those swabs very innacurate if not done in a timely manner??? I thought once the cough sets in, the window of getting an accurate diagnosis is much smaller.

the culture test is as useful as tits on a bull, becuase it requires to be done actually in the lab to get a decent result. Pertussis is very picky about it's growing conditions and any more than a 20 minute elapse to the lab and the likelihood of it growing is almost non-existent.

The PCR test is more than 90% accurate, and can be left sitting on the shelf for days, because it looks at DNA fragments, and doesn't matter if those fragments are dead or alive. Any doctor with a brain who REALLY wants to know does a PCR... never a culture.

[Momtezuma Tuatara]

Adenylate Cyclase Toxin cannot be in the vaccine, because it is activated once the infection process starts, and in response to the host immune system. That is why, as James D Cherry says, anyone "immune" from the vaccine, will continue to transmit pertussis around, because their body can't clear the bacteria efficiently after an "immunological original sin". What that means is that if the body learns to do something wrong the first time, that's the default setting for whatever comes after.

[wallacesmum]

So in order to get immunity from ACT, you HAVE to get a wild infection? And the antigenic original sin means that in any exposure to ACT from a wild infection, after immunization, the body will just carry the ACT around and pass it on?