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"Endangering Others"

post #1 of 11
Thread Starter 
There are few arguments more emotionally driven than the one that declining one or more vaccines "endangers" others. But is there any hard probability data available for the different vaccine-targeted diseases? For each vaccine-targeted disease, I'd be curious the likelihood of an unvaccinated person catching and spreading it. For weaker vaccines like mumps and aP, I'd be curious how vaccinated individuals came into play. I'd also be curious about morbidity and mortality figures, since some of the vaccine-targeted diseases *can* be mildly symptomatic or asymptomatic.

Maybe one of you math nerds can help me: How would we go about calculating these figures? What would the formula look like? What kinds of numbers would we need to crunch? What factors would we want to control for? Maybe overall vaccination rates, assuming we go by "herd immunity?" Quantifiable measures of how healthy or sanitary a population is?

I honestly doubt that such data is available. But it's fair to wonder if we're talking about a damning, imminent threat . . . or speculative, emotional fear-mongering based on lightning-strike statistics.

I do worry about disease outbreaks. I also worry about tsunamis, school shootings, and airline accidents. But because fear is such a powerful psychological force, it is interesting, when possible, to attach numbers to our fears.

I'm sure that someone will inevitably ask to run the similar numbers for vaccine reactions. Since most of those get explained away as coin-kee-deenks, however, I'm not sure how to go about that. But I'm open to ideas. smile.gif
post #2 of 11

subbing.

 

I think you have had so few responses as it is very difficult to figure out.

 

If you want to try, you are going to have to go one disease at a time.  Myself, I would start with flu, pertussis or even chicken pox…everything else is sufficiently rare that we might not have enough data to sort it out.

 

One of the variable you might need to account for is who is more likely to quarantine themselves if sick, be it voluntary (a choice they are making) or involuntarily (they are so sick they have to stay home).

 

You would need to look at methods of transmission and contagiousness at each stage.  For example, I was surprised to learn the flu is only contagious for one day before symptoms start.  Assuming you stay home once symptoms start, one day would not do a lot of damage compared, to say, pertussis - whose catarrah stage is a week or so.  Even still, an unvaxxed person with pertussis might be out and about for a week or two before they realise they might have pertussis, whereas a vaxxed person could be out and about for the whole duration - 8 weeks or so.  


Edited by kathymuggle - 1/21/14 at 10:16am
post #3 of 11
Quote:
Originally Posted by kathymuggle View Post
 

One of the variable you might need to account for is who is more likely to quarantine themselves if sick, be it voluntary (a choice they are making) or involuntarily (they are so sick they have to stay home).

 

True. For one thing, parents who don't vaccinate tend to be more aware of the symptoms of diseases for which there are vaccines, and they are more likely to consider them a possibility when their child is sick and has those symptoms.

 

Also, for pertussis, anyone can be infected and be a carrier. If the vaccine works as intended, (which it very often does not), it only reduces the symptoms in a vaccinated person. That person may feel good enough to go about their daily lives, and not think to avoid babies. Someone with the classic pertussis symptoms would be much more likely to avoid being around babies.

post #4 of 11
Thread Starter 
Hats off to the Vermont Coalition for Vaccine Choice for posting this link. It's the take on herd immunity from 1985, but you should read the part about heterogeneity of transmission, starting on page 326.

http://compepi.cs.uiowa.edu/uploads/Readings/Anderson85/anderson85.pdf

I think these factors would definitely play into quantifying endangerment.

If nothing else, this exercise is helpful to put all of the hysteria into perspective. As Barbara Loe Fischer recently and rightly pointed out, this nation has much, MUCH more urgent public health priorities. Infant mortality, anyone????
post #5 of 11

S*B*L=Ro

Pc = 1-1/Ro

S is the susceptibility of the disease, B is the infectious rate of the disease and L is the longevity of the disease. For example, if Ro is 20 then the percent of the population needing vaccinations is equal to 1-1/20 or 95%.

If Ro is 2 then 1-1/2 = 50% of the population. 

The higher Ro, the more infectious it is.

Each virus has a different Beta and each population has a different S. 

post #6 of 11
Quote:
Also, for pertussis, anyone can be infected and be a carrier. If the vaccine works as intended, (which it very often does not), it only reduces the symptoms in a vaccinated person. That person may feel good enough to go about their daily lives, and not think to avoid babies. Someone with the classic pertussis symptoms would be much more likely to avoid being around babies.

This post is entirely not accurate.

post #7 of 11
nm
post #8 of 11
Quote:

.  Even still, an unvaxxed person with pertussis might be out and about for a week or two before they realise they might have pertussis, whereas a vaxxed person could be out and about for the whole duration - 8 weeks or so.  

Um. What's your source for this?

post #9 of 11
Quote:
Originally Posted by Kyle Rutherford View Post
 

Um. What's your source for this?

As a "biologist", I am really surprised you have not read this study, because given your profession, I am sure you are able to get full access to it.

 

Acellular pertussis vaccines protect against disease but fail to prevent infection and transmission in a nonhuman primate model

 

http://www.pnas.org/content/111/2/787


 

Quote:

To test our hypothesis, infant baboons were vaccinated at 2, 4, and 6 mo of age with aP or whole-cell pertussis (wP) vaccines and challenged with B. pertussis at 7 mo. Infection was followed by quantifying colonization in nasopharyngeal washes and monitoring leukocytosis and symptoms. Baboons vaccinated with aP were protected from severe pertussis-associated symptoms but not from colonization, did not clear the infection faster than naïve animals, and readily transmitted B. pertussis to unvaccinated contacts. Vaccination with wP induced a more rapid clearance compared with naïve and aP-vaccinated animals. By comparison, previously infected animals were not colonized upon secondary infection. Although all vaccinated and previously infected animals had robust serum antibody responses, we found key differences in T-cell immunity. Previously infected animals and wP-vaccinated animals possess strong B. pertussis-specific T helper 17 (Th17) memory and Th1 memory, whereas aP vaccination induced a Th1/Th2 response instead. The observation that aP, which induces an immune response mismatched to that induced by natural infection, fails to prevent colonization or transmission provides a plausible explanation for the resurgence of pertussis and suggests that optimal control of pertussis will require the development of improved vaccines.

 

 

Baboons given DTaP - colonized with b. pertussis for 35 days

Baboons given DTP - colonized with b. pertussis 18 days

Baboons that recovered from natural infection - colonized with b. pertussis 0 days.

post #10 of 11

Interesting. I'll go ahead and read it when I have time.

post #11 of 11

Kyle, my source is the CDC, specifically the Pink Book.

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

 

"The first stage, the catarrhal stage, is characterized by the insidious onset of coryza (runny nose), sneezing, low-grade fever, and a mild, occasional cough, similar to the common cold. The cough gradually becomes more severe, and after 1–2 weeks, the second, or paroxysmal stage, begins. Fever is generally minimal throughout the course of the illness.

It is during the paroxysmal stage that the diagnosis of pertussis is usually suspected…..

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. Pertussis infection in these persons may be asymptomatic, or present as illness ranging from a mild cough illness to classic pertussis with persistent cough (i.e., lasting more than 7 days). Inspiratory whoop is not common."

 

 

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