Herd Immunity

[heathergirl67]

I've seen that some people don't believe in the theory of herd immunity. If you don't mind, could you tell me the reasons? Or if you believe in it, what are the reasons? Thanks!

[Marnica]

http://epirev.oxfordjournals.org/cgi...tract/15/2/265

http://www.vaccineriskawareness.com/...en-Like-Cattle

I think this is why some people doubt the concept.

Also only 10% of adults are up to date on their vaccines.....they need to be included in the numbers when it comes to herd immunity and they are not. Personally I think herd immunity may only be a valid concept in a select few number of diseases, and even then I have not made up my mind yet.

[heathergirl67]

Marnica- thank you for responding and for the links!

[Fyrestorm]

ITA - the 'herd' would have to include more than children. Most adults are far from up to date and vaccine immunity wanes.

I think the theory is based on a percentage (over 80%) if I remember correctly being immune. Taking lack of adult vaccination and vaccine failure into account, herd immunity is almost impossible.

I think we were closer to it when adults had natural immunity, but that doesn't exist anymore.

[ema-adama]

I am sure you could find plenty about this in the archives.

Having said that, I do believe that herd immunity is a real phenomenon. I do not know how successful vaccines are at providing herd immunity. I have not made up my mind, and this is obvisouly my opinion, but it looks like the measles vaccine provides herd immunity at the moment. I have read a paper discussing mathematical modeling that predicts measles outbreaks in highly vaccinated populations.
Mumps has a high failure rate, with repeated epidemics in highly vaccinated populations.
I question the sustainability of vaccine induced herd immunity in a disease like measles.

I know the OPV offered herd immunity. The IPV not. The IPV does not prevent transmission of the virus, but does protect the individual.

Hib seem to offer herb immunity, against Hib, but the issue of serotype replacement makes the true benefit of the vaccine questionable. (overal reduction of meningitis)

DTaP is not a herd immunity vaccine. Tetanus is not a communicable disease. The Diptheria portion does not prevent transmission, but protects the individual. The same with Pertussis. The vaccine does not interrupt transmission. And the pertussis portion is not as effective as for instance the measles vaccine.

My point? Saying that herd immunity exists and all vaccines have the ability to protect directly the vaccinated individual) and indirectly (the herd) is not a claim that stands up to closer scrutiny.

[heathergirl67]

Originally Posted by ema-adama

I am sure you could find plenty about this in the archives.

Good idea! I'm embarassed to admit that I never even thought of that.

[Deborah]

Archives are a good idea.

I agree that the vaccines have to be taken one at a time.

I honestly wince every time I see a news article blaming outbreaks of whooping cough on the unvaccinated population. That particular vaccine simply doesn't work that way.

But such news articles appear all the time and are never corrected by the CDC.

To give a very simple example:

When my granddaughter was a baby, she started out seeing a pediatrician. The ped told my daughter that she should vaccinate because of an outbreak of whooping cough.

My daughter asked what exactly was going on (she is an engineer). The ped replied that there had been 30 cases in the last year. My daughter asked who was catching the illness. The ped replied that it was teenagers whose vaccines had worn off, or something like that.

My daughter declined the vaccine, my granddaughter has never had a visible case of whooping cough (no one in my unvaxed family has ever had a visible case of this illness, although I know we have all been exposed, but some people just never get the symptoms).

The background to this is that there was a push to identify whooping cough in teenagers right around then because a vaccine for older kids and adults was in the works and how could they justify the vaccine if there weren't cases in kids and adults? So all of these cases were identified...but the same cases would have been called something else without this push.

I'll see if I can find an old thread pointing to the history.

This is a good old thread, but it is long, so I'm just going to link to a single post. You can read the entire thread if you want to as there is a lot of good info.
http://mothering.com/discussions/sho...1&postcount=52