Help me figure this out "vaccinated populations contain outbreaks"...

[Tee25]

So I read in a recent article that said, because most of the population is vaccinated, this is the reason that outbreaks are contained. If the population were not vaccinated, there would be an outbreak across the entire nation.

Trying, as a non-vaxer, to figure this one out.

[no5no5]

Okay, well, here's an example.  The relevant portion states:

A total of 6316 varicella cases were reported. Among children and adolescents aged 1 to 14 years, secondary attack rates varied according to age and by disease and vaccination status of the primary case and exposed household contacts. Among contacts aged 1 to 14 years exposed to unvaccinated cases, the secondary attack rate was 71.5% if they were unvaccinated and 15.1% if they were vaccinated (risk ratio [RR], 0.21; 95% confidence interval [CI], 0.15-0.30). Overall, vaccinated cases were half as contagious as unvaccinated cases. However, vaccinated cases with 50 lesions or more were similarly contagious as unvaccinated cases whereas those with fewer than 50 lesions were only one third as contagious (secondary attack rate, 23.4%; RR, 0.32 [95% CI, 0.19-0.53]). Vaccine effectiveness for prevention of all disease was 78.9% (95% CI, 69.7%-85.3%); moderate disease, 92% (50-500 lesions) and 100% (clinician visit); and severe disease, 100%.

In other words, vaccinated people had less severe disease and were less likely to contract and to transmit varicella (chicken pox). 

So in a group with mostly vaccinated individuals, the disease will spread much more slowly.  Obviously a disease that spreads slowly is much easier to contain than a disease that spreads quickly. 

[princesstutu]

More obviously, disease cannot really be contained without quarantining the entire exposed population, which is not going to be possible. 

[no5no5]

Originally Posted by princesstutu 

More obviously, disease cannot really be contained without quarantining the entire exposed population, which is not going to be possible. 

And yet, most outbreaks somehow are contained without quarantine. 

[pers]

By cutting out links in the chain of infection. 

Let's say a six-year-old (let's call him Andy) gets measles.   There is no vaccine, so measles is pretty common, but Andy happened to pick it up while traveling overseas with his family, so as far as his local is concerned, he is the origin for this particular outbreak.

There are twenty kids in Andy's class at school, including him, but three of them have had measles before so are immune.  That leaves sixteen kids he could potentially pass it on to.  During the period where he is contagious but not showing symptoms yet, he passes it on to three of those sixteen - two kids at lunch when he sneezes over their open lunchboxes and the kid at the desk next to him just from breathing the same air.  Those three other kids manage to pass it on to four other kids in their class, for a total of eight kids in the class getting it this go-around. Eight kids still have never had measles, but they will likely all have had it by the time they are ten. 

Of the eight kids from Andy's class who get sick, maybe one or two don't happen to have much contact with kids outside of class during the time they are contagious at school and then spend a weekend home away from other kids before being too sick to go back to school on Monday, but others pass it on two another kid or two, and some may pass it on to several.  

One of those kids passes it on to her best friend at a playdate, who passes it on to her little brother, who infects several kids at his daycare, including one who passes it to her older sister, who passes it to several kids in her class at school including Suzy is about to fly across the country to attend her Aunt's wedding, and will be bringing the measles as a gift to the other children there.  She also may pass it onto people at the airport or on the plane, potentially sending it in several different directions. 

Or another infected child passes it through a chain of ten kids to Billy, whose young cousins are in town visiting from another state and will take it home with them.  Or another who starts a chain of infection that includes, among many others, Emily, who is infected right before she leaves for a Disneyland for a week long vacation with her family. 

Now let's take another look at the chain that starts with Andy, but this time with vaccination.  Sixteen kids in Andy's class are immune thanks to vaccination.  Two kids are not immune despite being vaccinated, and two others (besides Andy) are not vaccinated, leaving four kids who he could potentially pass measles on to.  However, none of those four happens to be sitting near him when he sneezes on open lunchboxes, and none is the kid in the desk next to him, so the infection chain stops right there.

Or maybe he still does pass it on, but only to the one or two kids who are home alone during their most contagious periods and wouldn't have passed it on anyway, so it is contained to a single class.  Or maybe he still passes it to the girl who would have passed it to her best friend at the playdate, but her best friend is protected by vaccination, so doesn't get it.  Or maybe it makes it all the way to the daycare, but the child who passed it on to the older sister is well protected by his vaccine and so doesn't get it.  The point is, there are so many places where the chain of infection could be broken before it gets to Suzy, Billy, or Emily and taken out of town. 

Basically, it is just herd immunity.  It's not perfect, the disease could occasionally pass through just the right path of un-vaccinated and not immune despite vaccination people to infect someone who is about to travel and infect others at their destination.  But high levels of immunization decreasing the number of people who can get it, which decreases the number of cases and the chane that someone who is just about to travel out of town will get it and take it with them is why most measles outbreaks are contained to a specific geographic area rather than being spread widely around the country.  

Edited by pers - 3/25/11 at 6:51pm

[member234098]

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Edited by member234098 - 6/10/12 at 4:21pm

[no5no5]

Originally Posted by miriam 

If you look up the story of Leicester, England in the 1830s, that town used quarantine to avoid a smallpox epidemic and refused vaccinations.  Leicester had fewer cases of smallpox than the vaccinated towns.  The smallpox cases were quickly isolated and so were the persons who cared for them.  This is largely ignored by provaxers.

On the contrary, it is a fascinating example for anyone interested in public health.  There do seem to be two different versions of history circulating, however.  For the another side of the story, you might read this account. 

[member234098]

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Edited by member234098 - 6/10/12 at 4:19pm

[no5no5]

Originally Posted by miriam 

You do not think the NHIS have an agenda here?  

Quarantine and sanitation  have been a time honored method of preventing the spread of disease.  

I'd trust the NHIS before I'd trust whale.to.  I'm not sure what that has to do with anything, though.

And, yeah, quarantine has been used for thousands of years...as has vaccination.  We've gotten a great deal better at sanitation, and of course that's important too.  And the combination of all three has the best results, as we saw with the eradication of smallpox. 

[amnesiac]

Originally Posted by Tee25 

So I read in a recent article that said, because most of the population is vaccinated, this is the reason that outbreaks are contained. If the population were not vaccinated, there would be an outbreak across the entire nation.

Trying, as a non-vaxer, to figure this one out.

I suppose the assumption is that the population is not immune from previous infection either. As was demonstrated in the example pers provided, immunity is what broke the chain, regardless of whether it was immunity from the vaccine or prior disease.

[member234098]

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Edited by member234098 - 6/10/12 at 4:17pm

[no5no5]

Originally Posted by miriam 

I will take my chances with quarantine and sanitation since both are less likely to kill me.

That's your opinion.  My opinion is that disease is more likely to kill you (or someone you love) than a vaccine.   

[member234098]

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Edited by member234098 - 6/10/12 at 4:10pm

[no5no5]

Originally Posted by miriam 

My opinion is backed up by my life experience and research. Caring for vaccine damaged people is a labor of love that I see few doctors, nurses and pharmacrats doing. 

As is mine. 

I'm not sure what it is that you do for people who have had vaccine reactions, but my experience with medical professionals (including family members) is that they often make great sacrifices for anyone who needs medical help.  That doesn't mean that they spend a great deal of time dealing with people who have had vaccine reactions.  DH, for example, has never had a patient who had a reaction severe enough to require medical help.  So obviously he spends his time taking care of patients who need help with other problems. 

[heathergirl67]

OP- This could sound harsh, but I don't mean it that way. So I hope that you are able to recieve it in the spirit with which it's intended.

If you don't understand how immunity affects disease transmission then I don't think it's a good idea for you to be making decisions about infectious diseases for your kids.

[SilverMoon010]

Originally Posted by heathergirl67 

OP- This could sound harsh, but I don't mean it that way. So I hope that you are able to recieve it in the spirit with which it's intended.

If you don't understand how immunity affects disease transmission then I don't think it's a good idea for you to be making decisions about infectious diseases for your kids.

I don't know but this sounds awfully disrespectful no matter how it was intended.  Aren't we supposed to respect others and not make personal accusations?

[Tee25]

Originally Posted by heathergirl67 

OP- This could sound harsh, but I don't mean it that way. So I hope that you are able to receive it in the spirit with which it's intended.

If you don't understand how immunity affects disease transmission then I don't think it's a good idea for you to be making decisions about infectious diseases for your kids.

Hmm not sure that you can take that statement any other way THAN harsh lol. But I'll try I guess.

Actually, my question came off an article I was reading that involved about 2/3rds of "vaccine failures"...so maybe I should have posed my question better.

So are you saying that because someone doesn't understand the complexity of disease transmission completely (ie, fully vaxed people getting VPDs when exposed, not vaxed people not getting the disease when exposed) that also means they must not understand the risks/benefits of each disease and each vaccine separately? Not to mention how to treat each VPD if it were to occur? Not sure I understand where that correlation comes from in your line of thinking as it relates to making vaccine decisions. There is so much more to know about making a vaccine decision than just how disease transmission occurs in general populations...or why it occurs in vaccinated populations. I apologize if my question came off as ignorant in some way...I would hate to give anti-vaxers a bad name... [couldn't find a sarcastic smilie]

[rhiandmoi]

Originally Posted by miriam 

Quarantine and sanitation  have been a time honored method of preventing the spread of disease.  

Quarantine and exclusion are not the most effective means of controlling the spread of disease because they require every day citizens - most of whom feel the have no risk of contracting or spreading xyz disease - to greatly restrict their movements. The require the physical ability to isolate the healthy population from the infectious and the potentially infectious. They require a way to still provide medical care to those under quarantine. And even more politically, they require people who would be put under quarantine or exclusion to have a way to still earn their living while unable to go to work, so they have less incentive to break their exclusion orders and risk the general population. Sometimes it works really well. Especially if there is a short incubation period, and you get knocked on your butt really quickly by the symptoms. It's hard to spread sickness to the general population when you're lying on your bathroom floor wishing you would die. But sometimes it doesn't. And what should the consequences of breaking quarantine or exclusion orders during a pandemic be? Jail time? What if someone dies? Quarantine is still used today for many things, and people break it All The Time. You can't even imagine how hard it is to get some people to comply with quarantine orders, even when they have highly infectious diseases like TB and are actively symptomatic. People just do not like to have their movements restricted, and some people as long as they can still walk and aren't chained to their bed will find a way to get back out into the general population. But maybe that is what we should do. We might need a military force dedicated to quarantine and exclusion enforcement. :lol:

[rhiandmoi]

Also, has anyone read "A Prayer for the Dying". It's a novel - but an interesting portrayal of a small down during a disease outbreak.

[amnesiac]

Immunity or disease transmission aren't always factors in parents' vax decision making processes so I don't think we can make generalizations or recommendations to or about parents where that is concerned. If a parent objects to immunization based on religious or philosophical grounds, their understanding of infection and transmission have no bearing.

Just pointing out for those who might not be aware - there is a difference between quarantine and isolation. Isolating sick people is much easier than quarantining exposed but not sick people. I also think that those strategies were much more effective during times when society wasn't so mobile.