New ACIP guidelines - Tdap & pregnancy

[amnesiac]

Any thoughts on the ACIP's new "Prevention of Pertussis, Tetanus, and Diphtheria Among Pregnant and Postpartum Women and Their Infants" out last week?

http://www.cdc.gov/mmwr/PDF/rr/rr57e0514.pdf

[attachedmamaof3]

ugh.

[alegna]

SO don't have the patience to read the whole thing, but skimmed it. I have no respect for anything that sells itself to protect OTHERS against pertussis since the vaccine doesn't prevent transmission.

Just makes me discount the whole thing.

-Angela

[amnesiac]

Originally Posted by alegna

I have no respect for anything that sells itself to protect OTHERS against pertussis since the vaccine doesn't prevent transmission.

That's specifically what I was curious to hear discussion about - how their recommendations may or may not speak to that issue...

[alegna]

Originally Posted by amnesiac

That's specifically what I was curious to hear discussion about - how their recommendations may or may not speak to that issue...

Well, I didn't (as I mentioned ) read the whole thing.... feeling a touch impatient these days...

But it did at least INSINUATE that vaxing moms would reduce pertussis in newborns... :

-Angela

[mamakay]

Originally Posted by amnesiac

That's specifically what I was curious to hear discussion about - how their recommendations may or may not speak to that issue...

What they say is:

Vaccinating adults and adolescents using Tdap reduces the
burden of pertussis among vaccine recipients and might prevent
transmission of B. pertussis to infants (1,2).

Then their references are older MMWR recommendations. Tracking the original research down (IME) tends to be an exercise in futility for these things. They either cherry pick some obscure unreproduced findings from the 1970's or cite a study where an "expert panel" (of vaccinologists) was convened to make a wild guess.

Anywho...
This isn't any different from what they've been recommending all along.
They just left out the part about how HCPs who vax pregnant women are supposed to call 1-800-vaccine so the manufacturers can put a study together saying it's totally safe, so the ACIP can them make a firm recommendation instead of this wishy-washy "not contraindicated, but not recommended, exactly" stuff.
This is just another stepping stone for universal use in pregnancy.

I like how they word this:

Health-care personnel who have not been vaccinated with
Tdap (Table 2) can be an important source of pertussis and
pertussis outbreaks in obstetric and neonatal settings.

They don't out-right claim that HCPs who get the TDaP won't generally transmit the organism....they just imply it.

Oh, wait...reading the bottom...they did say call the registry:

Because information on the use of Tdap in pregnant women
is lacking, both manufacturers of Tdap have established a pregnancy
registry. Health-care providers are encouraged to
report vaccination of pregnant women with Tdap, regardless
of trimester, to the appropriate manufacturer’s registry. For
ADACEL,® vaccination should be reported to sanofi pasteur,
telephone [phone] (1-800-VACCINE), and for
BOOSTRIX,® vaccination should be reported to
GlaxoSmithKline Biologicals, telephone [phone].

I'd be surprised if the purpose of that wasn't to let the manufacturer produce the data on it's 100% safety, to justify universal use in pregnant women.

[amnesiac]

This subject comes up here a LOT & I think it's something that can be really confusing for a lot of people. Maybe it would be helpful to talk about what would need to happen in your body to prevent transmission & why the vaccine can or cannot accomplish that??

[alegna]

Originally Posted by amnesiac

This subject comes up here a LOT & I think it's something that can be really confusing for a lot of people. Maybe it would be helpful to talk about what would need to happen in your body to prevent transmission & why the vaccine can or cannot accomplish that??

To prevent transmission, the vaccine would have to prevent infection with the *bacteria*

The way this vaccine is made though it only works against the TOXIN, created by the bacteria, not the bacteria itself.

SO, everyone who has been vaxed can still get the BACTERIA and the vaccine (even if 100% and working perfectly) is only going to prevent the TOXIN from taking hold.

Simple summary by Angela

-Angela

[mamakay]

Originally Posted by amnesiac

This subject comes up here a LOT & I think it's something that can be really confusing for a lot of people. Maybe it would be helpful to talk about what would need to happen in your body to prevent transmission & why the vaccine can or cannot accomplish that??

That new website has some interesting stuff about it:


http://insidevaccines.com/wordpress/?page_id=148

[mamakay]

This thread also has some good info broken down:
http://www.mothering.com/discussions...d.php?t=555012

And starting with post #11 of this thread, there's some good info:
http://www.mothering.com/discussions...t=phagocytosis

In a nutshell, being vaccinated for pertussis does not help you clear the bacteria faster than if you weren't vaccinated. The randomized controlled trials clearly show that the vaccine *does* help you have a milder case of the disease, but just being immune to the toxin that screws up your lungs does that. But that won't necessarily mean that you still don't catch pertussis and go through the highly contagious period.

This is very different from something like measles, where, the chances are, after two doses of MMR, you probably won't be able to spread measles to someone else. (not for decades, at least).

Pertussis immunization doesn't appear to create "herd immuity" at all.

[amnesiac]

If a vaccine contains components other than PT, does that change anything? What about symptoms - does the vaccine alter any symptoms in infected people? Do symptoms affect transmission?

[mamakay]

If a vaccine contains components other than PT, does that change anything?

It should...but when you compare the effectiveness of the monocomponent PT vaccine to the 5 component high-tech acellular vaccine, there's not much difference there.
And point-blank...the other 4 components don't create a bactericidal immune response. For whatever complicated scientific reason, they just don't work. Or if they do, the effect must be very, very small.

What about symptoms - does the vaccine alter any symptoms in infected people?

Unless all the RCTs are fraudulent (which is unlikely) the vaccine significantly lessens the duration and severity of "the classic cough". That's the only thing you can say for sure.

Do symptoms affect transmission?

Most of the transmission happens before "the cough" sets in, so the fact that the vaccine lessens "the cough" doesn't mean that the vaccinated are less contagious.
They might be, but it hasn't been demonstrated to my knowledge.

[mamakay]

Here's a study on the monocomponent PT vaccine...
(I need to read it again)

http://www.journals.uchicago.edu/doi...10.1086/322639

ETA:
And here's one that's an RCT of the monocomponent PT.
http://content.nejm.org/cgi/content/full/333/16/1045

71-77% effective against a WHO criteria (which is a Very Bad Case) of pertussis..

And daptacel (a 5 component pertussis vaccine)
http://www.vaccineshoppe.com/US_PDF/...4757_12.03.pdf

Says it's 59-89% effective.
So I'm not seeing the other components doing much...

[amnesiac]

And supposedly Daptacel has the greatest efficacy of the DTaPs.

The reason I ask so many questions is that I actually just attended an event sponsored by a DTaP/Tdap manufacturer & was interested to hear some of the things being discussed. What do you all think about the Canada/Fewfoundland experience they like to cite?

I'd be surprised if the purpose of that wasn't to let the manufacturer produce the data on it's 100% safety, to justify universal use in pregnant women.

And I'd be interested to know in how far beyond delivery they're taking their surveillance since some of the concern voiced has been regarding possible interferance with the baby's response to DTaP in infancy.

[mamakay]

What do you all think about the Canada/Fewfoundland experience they like to cite?

Can you find a link?

And I'd be interested to know in how far beyond delivery they're taking their surveillance since some of the concern voiced has been regarding possible interferance with the baby's response to DTaP in infancy

I bet they're testing that now (or soon).
Would they have to register that in advance as a clinical trial?

[amnesiac]

Originally Posted by mamakay

Can you find a link?

This article has a crappy graph similar to the one I just saw Sanof.... er, that pharmaceutical company present the other day but I'm sure better links are out there:

http://www.clinicaladvisor.com/conte...howUid%5D=1608

[mamakay]

Originally Posted by amnesiac

This article has a crappy graph similar to the one I just saw Sanof.... er, that pharmaceutical company present the other day but I'm sure better links are out there:

http://www.clinicaladvisor.com/conte...howUid%5D=1608

Ok...here's the fulltext:

http://www.pubmedcentral.nih.gov/art...?artid=2095047

I think giving adults and teens boosters will result in some of them getting milder cases, so part of that is a "real" effect. With pertussis, misdiagnosis is always an issue, so some of the decrease is bound to a diagnostic illusion.

I'd like to see pertussis hospitilizations over the years. Those are more "solid" than reported cases.

[amnesiac]

The dude did make a reference to deaths being a better indicator. His rationale was that we're better at figuring out why someone died rather than being concerned with what's making them sick with the typical pertussis case.

[mamakay]

Originally Posted by amnesiac

The dude did make a reference to deaths being a better indicator. His rationale was that we're better at figuring out why someone died rather than being concerned with what's making them sick with the typical pertussis case.

Yeah, but for that small population, I doubt there would be any deaths either way hardly ever. We only have 25ish or so a year with the whole 4 million US birth cohort.

[amnesiac]

I don't know for certain that he was referencing that particular population when talking about the deaths because I wasn't paying much attention at that point. Already sat through the MCV4 portion & decided cheesecake was more important. :