Facts, not Fantasy

Tuesday, April 27, 2010

More vaccination news, some good, some not so good

I have a couple of news items from Dr. Plait's blog today. One is a collection of vaccine news, but another is a story that should hit home to people.

More vaccination news, some good, some not so good

Some vaccine news I missed in the past few days…

1) A pertussis outbreak in California has already killed two infants. This event resonates with what happened in Australia a year ago; vaccination rates are low, and the victims are too young to be vaccinated themselves. With herd immunities compromised, the littlest and most defenseless reap the effects. This is not necessarily caused by the antivaxxers, but it’s worth noting.

2) There is apparently a small outbreak of polio in Tajikistan. Vaccinations are critical, but so is sanitation.

3) PBS airs a documentary called "The Vaccine Wars" tonight. It’s about what you think it’s about. Check your local listings.

4) H1N1 is still out there, and still hurting and killing kids.

5) A bunch of kids got pretty sick after vaccinations in Australia. It’s unclear what happened, and officials are investigating it.

6) The good news? At least for Finland, it’s good: 97% of kids there are vaccinated. For everything. Amazing.

Tip o’ the needle to Antti Säämänen, Doug Troy, William Mount, and Greg Stitz.

Help a kid with leukemia… and help many, many more

Heather Steingruebl is a BABloggee. She contacted me and told me some chilling news: her daughter Elise was recently diagnosed with leukemia. She’s being treated, and I know we all hope things go well for her.

But in the meantime, this makes Elise susceptible to many preventable diseases. We need people to get vaccinated! As Heather says,

Vaccinate. Elise and thousands of kids like her are counting on not dying from things like measles and whooping cough while they fight cancer. Unless it’s a specific health risk to you or your child, just vaccinate. Please.

She also implores people to get on the bone marrow donation registry. Search around online for information on how to do this. I plan on doing this myself.

My heart goes out to her and her family, as it does to anyone affected by this awful illness. I’m going to find out what booster shots I need, because I take this issue very seriously. I hope you do too.

Wednesday, April 14, 2010

Let’s run the vaccine risk/benefit numbers!

I just found a blog called Photon In The Darkness, and plan to add it to my feed. The author has some great articles up, and I think that there will be plenty more. I would like to highlight one of them as an inaugural article from there. This is one of those cases where, as repeatedly stated, humans are very poor at assessing risk.

Let’s run the vaccine risk/benefit numbers!

March 12th, 2010

While reading another ‘blog, I found - in the comments - one of the worst examples of “bad epidemiology” I have ever seen. I won’t embarrass the commenter by name or by quoting, but the gist of their “argument” was that (in the US) the risk of vaccination exceeds the risk of the vaccine-preventable disease.

I think we’ve all heard that before.

There were many problems with their math, not the least of which was being too lazy to look up the actual numbers, but I realized that this was the tip of a much larger iceberg of innumeracy, especially as it pertains to understanding prevalence and risk.

So, to begin at the beginning, let us start with fractions.

Most of the time, risk or prevalence is expressed as a fraction, although it may not always look like a fraction (e.g. 1 in 100 is the same as the fraction 1/100). And - harkening back to our elementary school days - the two components of a fraction are the numerator (the top number) and the denominator (bottom number).

I bring up these apparently irrelevant mathematical issues because, in the world of risk and prevalence, there are two major types of errors: numerator errors and denominator errors (although, sometimes, there are errors of both).

In the example I mentioned above (the ‘blog comment), the risk of contracting a certain vaccine-preventable disease was calculated (wrongly, I must add) by dividing the number of people in the US who contracted that disease in a year by the population of the US. This was then stated - indirectly - to be the risk of an unvaccinated person contracting the disease.

Perhaps you’ve already noticed the error - it’s a denominator error. Since most people in the US are already immune to this disease (mostly by vaccination), the proper denominator would have been the number of unvaccinated people in the US. Let’s see how this changes the numbers:

If we use measles as an example, there were 140 cases of measles reported in 2008 (still compiling and verifying 2009 reports). At the end of 2008, according to the US Census Bureau, there were 300,459,786 people in the US. If we use the incorrect method from the example, that would give a “risk” of contracting measles of 0.47 per million per year (1 in 2,146,141 per year).

That seems a pretty low risk, doesn’t it? It’s a bit higher than your “risk” of winning the Powerball lottery, but still quite low.

But is it accurate? [Hint: No]

The correct way to calculate your risk of contracting measles is to divide the number of reported cases in the US by the number of vulnerable people in the US. By “vulnerable”, I mean those people who haven’t been vaccinated and haven’t had measles. That is a bit harder number to find.

The CDC’s NIS shows that, in 2008, 92.1% of children ages 19-35 months had received at least one MMR vaccination. Going back as far as 1994, that number seems fairly steady - about 90 - 92%. By the age of school entry, that percentage (in the 2007 - 2008 school year) was up to 94.9%. Even if we assume that this percentage doesn’t change, it would mean that - at most - 5% of the population is vulnerable to measles.

But even that isn’t an accurate number, because people born before the measles vaccine was available (1963) - and even the years immediately after the vaccine was introduced - would have gotten the disease if they weren’t vaccinated (it is highly contagious).

By 1968, the incidence of measles had dropped low enough to assume that anyone born after 1968 who was not vaccinated is not immune. So, that means that 5% of the US population age 41 or less is vulnerable to measles. This estimate compares with the value found by Hutchins et al (2004) for measles immunity in 1999, which supports the estimate.

According to the US Census Bureau, there are about 172 million people in the US age 41 years or less, so that gives us - at most - 8.6 million vulnerable people. Now the risk of contracting measles is 140 divided by 8.6 million or 16.3 per million per year (1 in 61,428).

After calculating the risk of contracting measles, we need to calculate the risk of death or serious complications. Measles has a case-fatality rate of 2 per thousand, so the risk of contracting measles and dying of it is about 0.03 per million per year - in the current situation, where 95% of the population is immune.

Other serious complications of measles include pneumonia (about 6% of cases) and encephalitis (1 per 1000 cases). Adding these to the risk of dying brings the total risk of serious complications to 0.8 per million per year. If we exclude pneumonia as a “serious” complication, the combined risk of contracting measles and having a permanent, life-altering (or life-ending) complication is 0.05 per million per year.

The risk of serious complications (i.e. death or permanent disability) from the MMR vaccine (discounting the as-yet-undemonstrated “autism connection”) is less than 1 per ten million doses (1 per million allergic reaction, less than 10% of which are “life threatening” = less than 1 per ten million), which (because the recommendation is two doses) works out to less than 0.2 per million per lifetime. With an average lifespan of 75 years, that works out to less than 0.003 per million per year, so the risk from the disease is over ten times greater than the risk of the vaccine even with 95% of the population immune.

Oh, and by the way - the MMR vaccine protects against three diseases, not just measles. We’ll just ignore that for right now.

And even this approximation doesn’t show the true risk of forgoing just the measles vaccine (let alone the MMR) because we haven’t considered how having a large immune population prevents spreading and how that has limited the number of measles cases reported.

Measles is transmitted from person-to-person, a single infection provides life-long immunity and it has no non-human reservoir and no known long-term carrier or dormant state. In this respect, it is similar to smallpox, polio, mumps, rubella, and many other vaccine-preventable diseases. If it is not transmitted, the measles virus “dies out”. It doesn’t “hang out” in the environment. That is why measles could be eradicated, just as smallpox was.

Currently (since 2000), measles is not endemic in the US, largely because there aren’t enough susceptible (non-immune) people in close enough contact to keep the virus going. Measles in the US is an imported disease that, until 2008, was rarely transmitted beyond the person importing it and any under-age (i.e. less than 2 years old) or immune-compromised people they came in contact with.

Starting in about 2008, the percentage of immune people in the US had slipped far enough that imported cases were able to spread locally in pockets of non-immune people. The August 22, 2008 edition of Morbidity and Mortality Weekly Report (MMWR) details two outbreaks of measles that occured in the US that year. In both cases, the outbreaks occured within groups that did not vaccinate for religious or philosophical reasons and were home-schooled.

This latter point is worth noting - even though these children did not attend a public or private school, they still contracted measles from one another.

Here is a telling statement from the MMWR report:

The number of measles cases reported during January 1–July 31, 2008, is the highest year-to-date since 1996. This increase was not the result of a greater number of imported cases, but was the result of greater viral transmission after importation into the United States, leading to a greater number of importation-associated cases. These importation-associated cases have occurred largely among school-aged children who were eligible for vaccination but whose parents chose not to have them vaccinated. [emphasis added]

As the percentage of non-immune people in the country rises, imported measles cases will spread to more people, further raising the risk of infection to non-immune people and increasing the already large benefit to risk ratio of vaccines.

What this shows is that those people who choose to not vaccinate should - at the least - take precautions against associating with other people who don’t vaccinate. This would help reduce their risk of infection to the levels I calculated above.

Perhaps they should wear some sort of lapel pin, similar to what many fraternal organisations (e.g. Masons, Rotarians, etc.) have. Except, of course, that instead of stepping forward and embracing when they see a fellow member (with or without secret handshake), they should immediately turn about and walk briskly in opposite directions, to avoid transmitting vaccine-preventable diseases.

As the events of 2008 showed us, there will not be a gradual increase in measles spread as vaccine coverage declines - there will most likely be an abrupt increase as the percentage of non-immune people (and their proximity to one another) crosses a critical threshold.

And it is important to note that non-immune people are not just the children of parents who choose not to have them vaccinated. They include children too young to be vaccinated and people who are immune-suppressed due to disease, cancer or genetic disorders. They include the elderly, whose immune systems are weaker, and those people who - for one reason or another - did not develop an adequate immune response to vaccination.

Those who choose to not vaccinate and think they are letting others take the risks for them are fooling themselves; they are taking the greater risk - even now.


Non-hyperlinked References:

Hutchins SS, Bellini WJ, Coronado V, et al. Population immunity to measles in the United States, 1999. J. Infec. Dis.. 2004; 189(Suppl 1):S91–7

Sunday, April 11, 2010

Measels outbreak because anti-vax is dangerous

Measles Resurgence Tied To Parents' Vaccine Fears

A generation ago, up to 4 million U.S. children got measles every year. Hundreds died, and thousands were left with permanent brain damage. Thanks to vaccination, those days are over, at least in this hemisphere. But health officials worry about the growing number of children who are vulnerable when somebody brings measles from another part of the world.

It happens regularly. Vancouver is trying to contain a measles outbreak sparked when foreign travelers visited for the Olympics, carrying two different measles viruses from Asia.

The first recognized infections — in two Canadians and a visiting American — occurred around the Olympic closing ceremonies. "Downtown Vancouver was shoulder-to-shoulder on many days of that period," notes Dr. Monika Naus of the British Columbia Centre for Disease Control.

So far, measles has spread to 16 people in Vancouver, Naus says. Half of them are in one large unvaccinated household. The parents reject vaccination.

"It's not a religious issue," Naus says. "A friend of the family who had anti-vaccination sentiments was influential in convincing them not to get vaccinated."

Many parents who refuse to get their children vaccinated worry that vaccines — and the one for measles, mumps and rubella in particular — cause autism. It's a belief that persists despite years of studies and expert panels that find no scientific link.

Health officials say there are growing pockets of vaccine refusers in communities across the land. The numbers are not great. But these pockets of "intentionally unvaccinated" children give the virus more opportunities to spread when it does arrive.

And even if the number of measles cases in each outbreak is kept small, the arrival of measles disrupts lives and forces public health officials into high gear to contain the damage.

Ask Karen Waters-Montijo, chief of immunization at the San Diego County health agency. She and her colleagues, including officials at the U.S. Centers for Disease Control and Prevention in Atlanta, write about the impact of a 2008 measles outbreak in the April issue of the journal Pediatrics.

Waters remembers the February day when a public health nurse called to report a confirmed case of measles: a 7-year-old boy who had picked up the virus during a family trip to Switzerland.

As unlikely as it seems, Switzerland is one of those European countries where measles vaccination rates have fallen considerably below 95 percent — the level public health officials say is necessary to prevent measles from circulating in the community.

When Waters heard about the case, she says, "I just about fell off my chair. The child had two siblings, attended public school. The family wasn't vaccinated. And in fact, there were a lot of unvaccinated children at the school, as well."

They were "intentionally unvaccinated," meaning their parents had filed Personal Beliefs Exemption forms to opt out of the vaccinations that are required for schoolchildren. Parents of almost 10 percent of the students at Patient Zero's school had signed PBE forms.

That may not sound like much. But no virus is more contagious than measles. "If a measles-infected person walks into a room with 10 uninfected people," says Dr. David Sugerman of the CDC, "nine of them will get infected."

Moreover, anyone who goes into that room within the next two hours after the infected person has left is likely to get measles, too.

So Waters and her colleagues were alarmed when they learned that it had taken a week before the measles infection of Patient Zero was diagnosed. In the meantime, he had exposed many people in doctors offices and clinic waiting rooms, as well as in school. He had also infected his siblings, and they had exposed many others.

"It was slow to be recognized, and there's a good reason for that," Waters says. "We hardly ever see any measles cases. Most doctors have never seen a case." Once the first patient was diagnosed, moreover, health authorities were slow to be notified.

Once they found out, health authorities kicked into gear, tracing everybody who came into contact with the first cases — and everybody who was in contact with them. That net captured people who got exposed (and, in some instances, infected) at supermarkets, circus performances, fairgrounds and a Hawaii-bound airplane.

It added up to 839 people. Of those, 73 were unvaccinated children — 25 whose parents chose not to get them vaccinated, and 48 children under 12 months who were too young to be vaccinated.

To limit the spread of the virus, San Diego County officials asked parents of those 73 children to keep them at home. Many of them were pretty unhappy about that.

"Imagine, you start off on a normal day," Waters says, "and you're getting ready to drop your child off at their child care place, and you're greeted by a public health nurse who says your child has been exposed to measles, and we'd like you to go home and be there for the next three weeks while we monitor you for symptoms."

Parents of exposed children who believed in vaccination were incredulous and angry, she says: "They said, 'What do you mean, people don't get vaccinated? Why is this happening?' "

In the end, the San Diego outbreak was confined to a dozen children. No big deal, you might think — except that it upended a lot of lives, and the county spent $10,000 for each of those cases in order to keep the virus from spreading more widely. That, and the fact that more than 95 percent of the general population was immune, kept the outbreak far more limited than the previous San Diego measles outbreak in 1991, when there were 1,000 cases and three deaths.

Afterward, Waters and her colleagues looked into who the vaccine refusers were and what their attitudes toward vaccination were.

They're college educated, higher-income and believers in the power of a "natural" lifestyle — things like organic food and prolonged breast-feeding — to keep their children's immunity strong enough to ward off vaccine-preventable diseases.

And they just don't believe it when government officials like Karen Waters say vaccines don't cause autism.

"It is wrapped up in their attitudes about government," Waters says. "I don't think they think I'm the enemy. I think they think I'm well-intended but misinformed."

Many communities have pockets of vaccine refusers. So the United States and other countries with growing numbers of "intentionally unvaccinated" people are likely to see more outbreaks.

There's bound to be occasional importation of measles from countries with circulating virus. These aren't only developing nations; they include Ireland, Germany, Israel, Japan and the United Kingdom, where measles had been eliminated until large numbers of parents started opting out of vaccination programs.

CDC officials are watching the Vancouver outbreak closely, as neighboring Washington state has sizable populations of vaccine refusers.

"If measles crossed the border into those populations, there's a potential for a sizable outbreak," says Dr. Jane Seward of the CDC.

Back in San Diego, Karen Waters is still trying to persuade skeptical parents to get their children vaccinated. She says refusers are not bad guys in this drama.

"You know, these are very nice people," she says. "They care a lot about children, as I do. We all want safe vaccines. We all want healthy children, and we all want answers about autism. It's unfortunate there's a group of people who are off on this track, that believe vaccines are at the root of this problem."

So far Waters hasn't changed many minds. She knows of a thousand families who have refused to get their kindergartners vaccinated. That's 100 more since that last San Diego measles outbreak.

Thursday, April 08, 2010

Why I HATE the term "Missing Link"

The popular press will readily describe ANY kind of newly discovered hominid fossil as a missing link, which for 99% of the time is just BS as there wasn’t any missing link before the find. Additionally, it is almost always claimed that it will “rewrite our understanding of the history of the human species” or some such tripe.

The press blows a lot of science out of proportion and helps to mess up the general public’s understanding of what’s going on. This will certainly not, “rewrite the history of human evolution by filling in crucial gaps in the scientific knowledge.” It certainly will give us more knowledge and fill in details that were previously fuzzy. Wording like this keeps people unreasonably skeptical of science, making them think that scientists have no idea what they are talking about because every new thing “rewrites” our understanding. If everything says everything else is false, why should we trust science? And then the media turns around and makes fun of people for being “ignorant”…

This looks like an interesting find that will add to our existing knowledge of human evolution – all fine and good, but it’s not revolutionary in any way since its discovery really was to be expected from what we already knew.

New Hominid Shares Traits With Homo Species: Fossil Find Sheds Light on the Transition to Homo Genus from Earlier Hominids

Two partial skeletons unearthed from a cave in South Africa belong to a previously unclassified species of hominid that is now shedding new light on the evolution of our own species, Homo sapiens, researchers say. The newly documented species, called Australopithecus sediba, was an upright walker that shared many physical traits with the earliest known Homo species -- and its introduction into the fossil record might answer some key questions about what it means to be human.

The fossils are between 1.95 and 1.78 million years old, and in this week's issue of Science, the peer-reviewed journal published by AAAS, the nonprofit science society, two reports describe both the physical characteristics of this new Australopithecus species as well as the ancient environment in which it lived and died. The emerging picture is one of a hominid with a bone structure similar to the earliest Homo species, but who employed it more as an Australopithecus, like the famed "Lucy," would have.

These new fossils, however, represent a hominid that appeared approximately one million years later than Lucy, and their features imply that the transition from earlier hominids to the Homo genus occurred in very slow stages, with various Homo-like species emerging first.

"It is not possible to establish the precise phylogenetic position of Australopithecus sediba in relation to various species assigned to early Homo," wrote Lee Berger, a lead author of one of the Science reports. "We can conclude that… this new species shares more derived features with early Homo than any other known australopith species, and thus represents a candidate ancestor for the genus, or a sister group to a close ancestor that persisted for some time after the first appearance of Homo."

Many scientists believe that the human genus Homo evolved from Australopithecus a little more than two million years ago -- but the origin has been widely debated, with other experts proposing an evolution from the Kenyanthropus genus. This new Australopithecus sediba species might eventually clear up that debate, and help to reveal our direct human ancestors.

"Before this discovery, you could pretty much fit the entire record of fossils that are candidates for the origin of the genus Homo from this time period onto a small table. But, with the discovery of Australopithecus sediba and the wealth of fossils we've recovered -- and are recovering -- that has changed dramatically," Berger said.

The name itself, "sediba," means "fountain" or "wellspring" in the seSotho language, spoken in South Africa, and indeed, researchers do believe that the new fossils will provide a wealth of information about our human origins.

For now, these new hominid fossils make it clear that the evolutionary transition from small-bodied, and perhaps more tree-dwelling, ancestors to larger-bodied, full-striding bipeds occurred in gradual steps.

Berger, from the University of Witwatersrand in South Africa, along with Paul Dirks from James Cook University in Australia began a study on the distribution of cave deposits in the Cradle of Humankind -- a World Heritage Site, set aside for its physical and cultural significance -- in January 2008. Months later, Berger discovered the two partial skeletons in cave deposits at Malapa, South Africa, and analyzed the remains, including most of a skull, pelvis, and ankle of the new species with colleagues from the U.S., Switzerland, and Australia.

The two Australopithecus sediba -- an adult female and a juvenile male -- were found close together in a portion of the cave system that had been protected from scavengers, so the fossils are very well-preserved. The researchers describe the hominid's physical traits, highlighting the unique pelvic features and small teeth that it shared with early Homo species. Based on its physique, they suggest that the new species descended from Australopithecus africanus, and that the hominid's appearance signified the dawn of more energy-efficient walking and running.

"These fossils give us an extraordinarily detailed look into a new chapter of human evolution, and provide a window into a critical period when hominids made the committed change from dependency on life in the trees to life on the ground," said Berger. "Australopithecus sediba appears to present a mosaic of features demonstrating an animal comfortable in both worlds."

In a separate report published in Science, Paul Dirks and colleagues from around the world analyze the Malapa cave system, date the fossil deposits, and describe the geological and ecological environment that Australopithecus sediba would have dwelled in long ago.

"We think the environment sediba lived in was, in many ways, similar to the environment today," Dirks said. "For example, one with predominantly grassy plains, transected by more vegetated, wooded valleys. However, the rivers flowed in different directions and the landscape was not static, but changed all the time."

The caves at Malapa are not randomly distributed, but occur along fracture zones that criss-cross the landscape. They consist of mostly quartz, chert, dolomite, and peloids -- though there are also iron-oxide coated grains, ooids, shale, and feldspar in the rocks.

"The fossils occur together in a near-articulated state in the sedimentary remains of a deeply eroded cave system," Dirks continued. "They were laid down by a single debris flow, indicating the timing of their deaths were closely related and occurred shortly before the debris flow carried them to their place of burial."

The researchers identified the fossils of at least 25 other species of animals, including saber-toothed cats, a wildcat, a brown hyena, a wild dog, antelopes, and a horse in the cave as well. They suggest that the Malapa caves were tens of meters deep when the Australopithecus sediba fossils were deposited -- and also propose that the cave dwelling could have acted as a death trap for animals seeking water.

"One possible explanation for their entry into the cave could have been that they needed water," said Dirks. "To explain the fossil assemblage and their well-preserved state, we would speculate that perhaps at the time of their death, the area in which sediba lived experienced a severe drought… Animals may have smelled the water, ventured in too deep, fallen down hidden shafts in the pitch dark, or got lost and died."

Sunday, April 04, 2010

Science writer Simon Singh wins libel appeal

More good news for the forces of reality.

A science writer has won the right to rely on the defence of fair comment in a libel action, in a landmark ruling at the Court of Appeal.

Simon Singh was accused of libel by the British Chiropractic Association over an article in the Guardian in 2008.

Dr Singh questioned the claims of some chiropractors over the treatment of certain childhood conditions.

The High Court had said the words were fact not opinion - meaning Dr Singh could not use the fair comment defence.

However, the Lord Chief Justice Lord Judge, Master of the Rolls Lord Neuberger and Lord Justice Sedley ruled High Court judge Mr Justice Eady had "erred in his approach" last May, and allowed Dr Singh's appeal.

BBC News science correspondent Pallab Ghosh says that, had Justice Eady's ruling stood, it would have made it difficult for any scientist or science journalist to question claims made by companies or organisations without opening themselves up to a libel action that would be hard to win.

Dr Singh described the ruling as "brilliant", but added that the action had cost £200,000 "just to define the meaning of a few words".

"After two years of battling in this libel case, at last we've got a good decision. So instead of battling uphill we're fighting with the wind behind us," he said.

"The Court of Appeal's made a very wise decision, but it just shouldn't be so horrendously expensive for a journalist or an academic journal or a scientist to defend what they mean.

"That's why people back off from saying what they really mean."

The British Chiropractic Association said it was disappointed to lose the appeal but it was "not the end of the road".

BCA president Richard Brown said: "We are considering whether to seek permission to appeal to the Supreme Court and subsequently proceed to trial.

"Our original argument remains that our reputation has been damaged. The BCA brought this claim only to uphold its good name and protect its reputation, honesty and integrity".

In the article in April 2008, Dr Singh suggested there was a lack of evidence for the claims some chiropractors made on treating certain childhood conditions such as colic and asthma.

The BCA alleged that Dr Singh had effectively accused its leaders of knowingly supporting bogus treatments.

The case has become a cause celebre for the science community and led to calls for defamation law to be rewritten so it does not interfere with scientific debates.

His high-profile supporters include Stephen Fry, Ricky Gervais and Harry Hill, all from the world of entertainment.

Dr Singh said: "The judges are clearly unhappy on how libel laws can impact on discussion, on how this libel suit has quashed debate about chiropractics to a large extent.

"They're particularly unhappy about the way scientific discussion can be silenced by libel laws. That's a real boost to the libel reform campaign."

Coalition for Libel Reform spokeswoman Tracey Brown said: "This case has brought out of the woodwork the fact that so many other discussions are being killed, from discussions of cardiology to human rights to medicines.

"We're now pushing ahead for bigger changes to the law so that we have the kind of public interest defence that means it wouldn't have taken two years and £200,000 to find out whether Simon can defend himself."

British scientific organisation the Royal Institution welcomed the judgement.

Director of programmes Gail Cardew said: "It will encourage scientists and the public to discuss evidence freely without fear of legal threat."

Thursday, April 01, 2010

Quick Post from Dr. Plait

I have been swamped with numerous other duties, and my team of collaborators have not had a chance to take up the slack. Thus, i just wanted to copy/paste a couple of real quick posts from Dr. Plait that may be of interest to you:

More truth-based weapons against the antivaxxers

A few antivax links for your amusement:

1) When challenged about their bizarre and provably false beliefs, a lot of antivaxxers claim that they have personal experience with their kid. That’s anecdotal and uses a small sample size, and so is prone to all sorts of logical failings. But what if the sample size is much larger and uses scientific reasoning? Then you get something like this good spanking of antivax nonsense by an actual pediatrician.

Tip o’ the syringe to David Whalley.

2) The Australian Vaccination Network is one of the most pernicious and awful of the antivax groups, as regular readers know. They may be on their way out — science, apparently, can inoculate us against such infections — but it’s still worth keeping up with the sort of offal they spew, since other groups do it as well. This article by The Australian Skeptics is an excellent exposé of AVN mendacity.

3) Healthday has an alarming article about the San Diego 2008 measles outbreak which exposed over 800 people because one family decided not to vaccinate their kid. Yes, one family started an minor epidemic that cost over $170,000 to contain and nearly killed one infant. I hope antivaxxers are proud of that one.

4) Orac once again leaps into the fray with a magnificent exposure of some bold antivax lies. It’s amazing to me just how low some antivaxxers are wiling to go — cheating, twisting, distorting, and out-and-out lying — to promote their agenda of bringing back preventable diseases.

They say they care about kids. Maybe they do. But making sure children get measles, rubella, pertussis, and other life-and-limb-threatening diseases is sure a funny way of showing it.

Taking the Plunge

Dylan Otto Krider wrote a nice piece about antivaxxers in the Denver magazine recently. He interviewed me for it, and I’m pleased with how it came out. Otto is one of the good guys, and one of the few in the MSM willing to take this topic on without pandering to nonsense to provide false "balance":

One of [Plait's] latest causes has been debunking the antivax movement that he sees as dangerous. “They don’t have anything to stand on except emotions,” he says. “They play on the heartstrings, and unfortunately, people tend to listen to their emotions.”

He says the antivax movement is having an effect. “You can see it,” he says. “The number of people getting vaccines is going down.” What he finds particularly annoying is that when things change — for example, thimerosal has been largely, although not entirely, eliminated as a preservative in vaccines — antivax groups just “move the goalposts” and claim vaccines do something else.

I’m glad to see this getting more press, and I’m very glad to see the antivaxxers getting hit harder and harder. Every time their garbage is aired out, a few more kids get a chance to live a life with a lower risk for preventable diseases.