Search Results for "vaccine"

Sep 11 2020

COVID Vaccine News

By now most people have heard that AstraZeneca, a UK pharmaceutical, working with Oxford University, are one of the major companies developing a vaccine for SARS-CoV-2, and also that they have had to pause their Phase 3 clinical trial because a subject came down with an inflammatory disorder. Let’s put this into some important context.

The basic facts are that the AstraZeneca vaccine did very well in Phase 1 and 2 preliminary trials. These are smaller trials mostly about safety, with the Phase 2 trial including some preliminary (usually open label) efficacy data. These trials are basically used to determine if it is safe and worth it to proceed to a huge Phase 3 trial. The Phase 3 trial includes 30,000 subjects. When you increase the number of subjects by orders of magnitude then you are likely to pick up increasingly rare side effects. That is one of the main points of this staged approach to research. Then, of course, a drug or vaccine might be marketed to millions of people, and still more rare side effects will crop up. There is simply no way to avoid this – it’s math. That is why so-called Phase 4 trials follow reported side effects after market.

But also, when you are studying 30,000 subjects all the things that normally happen to people will happen at the background frequency. Some of them will get sick during the trial by chance alone, having nothing to do with the study drug or vaccine. So every potential adverse effect is tracked, determined if it is biologically likely that it is related to the experimental treatment, and then statistically analyzed to see if it is above the background rate.

In this case one subject developed transverse myelitis, which is inflammation in one segment of the spinal cord. This will cause weakness and numbness at that level and below, therefore usually affecting the legs. The background incidence of transverse myelitis is about 1.3-4.6 cases per million people per year (this does not include people known to have an autoimmune disease like MS that causes transverse myelitis). If we take 4 cases per million per year, that translates to 0.033 cases per 33,000 subjects over three months. That is the probability that one of the subjects in that trial would have randomly developed transverse myelitis. That may seem really unlikely, but actually you have to consider the probability of a subject developing any disease, not just transverse myelitis. When you add it all up it’s actually pretty likely that one or several people in the trial would randomly develop a disease not related to the vaccine. In fact, this is the second person in this particular trial to develop a serious potential adverse event resulting in a pause of the trial.

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May 04 2020

COVID-19 Immunity and Vaccines

We appear to be at the beginning of the end of the first wave of COVID-19 (at least in the US – other countries are at different places). We are at the point where states are starting to relax the physical distancing requirements, and there is discussion about how to transition to the next phase. That next phase might include disease tracking, targeted isolation, and “immunity passports.” But planning this next phase is complicated by the fact that we still do not fully understand this virus. We don’t know if there will be a second wave (or more), if it is seasonal, and if you can catch it twice. How we handle this next phase will likely determine if there is a second wave.

But what comes after that? When can we transition to the final phase – return to normal, even if it is a new normal? These next transitions will depend largely on the natural immunity that results from infection, and how long it will take to create a vaccine and how effective that vaccine is. Here is what we know and don’t know so far.

The big question for the next phase is – how much immunity results from natural infection? This is a more complicated question than it may first seem. But the short answer is, we don’t know.

The adaptive part of the immune system will remember infections, B-cells that create specific antibodies targeting the infecting organism will develop throughout an infection, and some of those B-cells are memory B-cells – they will hang around for a long time, ready to produce specific antibodies the next time the same organism is encountered. But there are important variables to how effective this adaptive immune strategy is. the virus or infecting organism itself is the main variable. What parts of itself does it expose to the immune system? Perhaps the critical functional proteins are hidden deep within folds that antibodies cannot get to. Another variable is how quickly does it mutate? If the parts that antibodies can target change quickly, then immunity does not last. Some organisms also evolve specific strategies to evade or compromise the immune system.

Another variable is the severity of the infection itself. The more severe and long lasting the infection, the greater the stimulation to the immune system and the greater the adaptive response.

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Mar 05 2019

Study – Still No Link Between Autism and MMR Vaccine

Published by under autism,Science Denial

I know this is old news – or at least it should be – but it bears repeating, especially as we are in the midst of a resurgence of measles. There is no link between the mumps, measles, and rubella vaccine (MMR) and autism, or any neurological disorder. A new study confirms this lack of association. This should go a long way to reassure the vaccine hesitant that the MMR vaccine at least is safe and should not be avoided.

This is a Danish study, and the largest study of the MMR vaccine and autism to date – “657,461 children born in Denmark from 1999 through 31 December 2010, with follow-up from 1 year of age and through 31 August 2013.” They found:

During 5,025,754 person-years of follow-up, 6517 children were diagnosed with autism (incidence rate, 129.7 per 100,000 person-years). Comparing MMR-vaccinated with MMR-unvaccinated children yielded a fully adjusted autism hazard ratio of 0.93 (95% CI, 0.85 to 1.02). Similarly, no increased risk for autism after MMR vaccination was consistently observed in subgroups of children defined according to sibling history of autism, autism risk factors (based on a disease risk score) or other childhood vaccinations, or during specified time periods after vaccination.

Overall there was no association between getting the MMR vaccine and later being diagnosed with autism. Further, there was no correlation when looking specifically at children who have a sibling with autism, and therefore might constitute a susceptible subpopulation. Further still, there was no clustering of autism diagnosis following the MMR vaccine administration, as might be expected if there was a causal link. This is a very large study with an adequate study design, so that if there were any increased risk of developing autism from the MMR vaccine we should be seeing it in this data – and we don’t.

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Aug 13 2018

Dunning Kruger Effect and Anti-Vaccine Attitudes

One of the persistent themes of this blog is that expertise matters. This is not to say the experts are always right (sometimes they disagree with each-other), and there is also a range of expertise, and different kinds of experts can have different biases and blind spots. But all things considered, someone who has formal expertise on a specific topic is likely to know much more about that topic than someone who has read about it on the internet.

Further, most people underestimate the amount of knowledge that exists on a topic, and therefore the vast gulf of knowledge that exists between them and the experts. In fact, the more someone knows about a topic the more they understand how much is known, and the more humble they tend to be with respect to their own knowledge. The flip side of this – people who know little tend to overestimate their relative knowledge – is an established psychological phenomenon known as the Dunning-Kruger effect.

Operationally Dunning and Kruger found in their study that the lower someone performed on a test of knowledge, the greater the gap between their perceived knowledge and performance and their actual performance. At around the 80th percentile and above, people tend to underestimate their relative knowledge. Below that point they tend to increasingly overestimate it, and everyone thinks they are above 50%.

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Aug 03 2018

Placebo Controlled Trials of Vaccines

There is a strong scientific consensus that vaccines generally are an effective approach to preventing infectious illness. The vaccine schedule is arguably the most effective and cost effective health promotion intervention ever devised. Vaccines are a public health home-run.

How, then, to explain the anti-vaccine movement? The anti-vaccine movement is based mainly on science-denial and conspiracy theories. This means they spread a lot of misinformation – the bits of misinformation become articles of faith, and any evidence to the contrary is denied or dismissed.

I recently received the following question, which is framed as a sincere question, but I have my suspicions that it may not be:

Have just read your article.

I fully agree that herbal medicines/substances should have full clinical trials but can never find anyone able to refer me to
any clinical trials placebo versus substance to be tested on vaccines.
So wondered if you could help me as you are obviously a man of science.
Would be very grateful as there must have been clinical trials sometime.
Even my Dr draws a blank.
Many thanks
Pam

Pam may simply be the victim of anti-vaccine propaganda, and may simply lack all Google skills, but the phrasing strongly suggests an anti-vaxxer goading a skeptic with a “gotcha” question. Since this is a common anti-vaccine trope, let me dispel it once again.

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Oct 12 2017

Another Antivaccine Retraction

Retracted-950x633Science only works when it works.

In other words – science itself does not lead to an understanding of the universe unless that science is done correctly, rigorously, and honestly. This is a lot harder than I think is generally appreciated. In order to really reach firm scientific conclusions about any complex question we need to follow the arch of the research as it matures. We need to see what overall patterns emerge in the evidence. Eventually a tentative but reliable scientific consensus can be achieved.

There are many ways in which this process can go off the rails, however. With ESP we see researchers chasing the noise – trying to find tiny signals but only chasing their tails. With acupuncture we see proponents choosing to ignore, misinterpret, and then abandon well-controlled clinical trials in favor of “pragmatic” studies that will show them what they want. There is “cargo cult” science that goes through the superficial motions but lacks true scientific methodology. There is “Tooth Fairy” science that nibbles around the edges but never addresses the core premise – is the phenomenon actually real?

There is a huge positive bias in science – researchers have a tendency to tweak their methods to get the results they want, publishers have a tendency to publish positive exciting research, and other scientists have a bias toward citing positive interesting research. Funding sources affect research outcome. When pharmaceutical companies fund research the results are much more likely to be favorable to their drug than independent research. Scientists make mistakes, take shortcuts, and often have blinders on. And then there is outright fraud, which is uncommon but still crops up on a regular basis.

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Sep 25 2017

Lying About Vaccines

Robert F. Kennedy Jr. talks with reporters in the lobby of Trump Tower in New York, Tuesday, Jan. 10, 2017, after meeting with President-elect Donald Trump. (AP Photo/Evan Vucci) Robert F. Kennedy Jr. talks with reporters in the lobby of Trump Tower in New York, Tuesday, Jan. 10, 2017, after meeting with President-elect Donald Trump. (AP Photo/Evan Vucci)[/caption]

Robert F. Kennedy Jr. considers himself an environmentalist. While advocating for the environment, he has become particularly concerned about the effects of mercury on human health. This in itself is reasonable, and there is broad scientific agreement that we should make efforts to minimize human exposure to mercury.

But Kennedy goes beyond reasonable recommendations based upon scientific consensus. He has become part of what we call, “The Mercury Militia” who have become unmoored from reality in their zeal to combat the perceived evils of mercury. The mercury militia further became tied to the anti-vaccine movement when it was claimed that the mercury in some vaccines was causing harm (it doesn’t). He has become a visible example of how someone can cocoon themselves in their own reality.

In a recent interview for Stat News Kennedy tells a number of falsehoods about vaccines. In essence he is lying, although it is possible he believes the lies he tells. Kennedy has apparently dedicated a large portion of his life to this issue, publicly advocates for his position, and certainly has resources at his disposal. And yet he gets basic facts about vaccines hopelessly wrong. How does that happen?

Paul Offit has written an excellent take down of Kennedy’s interview, explaining many of his falsehoods. For example, in the interview Kennedy claims: Continue Reading »

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Sep 07 2017

Eliminating Personal Belief Exemptions for Vaccines

ExImmunMap15-TuesdayIn the US routine childhood vaccination is required for entry into public school, and in some states even private school. This is a reasonable public health policy. Vaccination not only protects the individual against common infectious diseases, but when enough people get vaccinated this creates community immunity (often referred to as herd immunity) which protects everyone.

Any parent knows first hand that children are seething vectors for germs. Their concept of hygiene, generally speaking, is often not the same as the average adult. Put a large group of children together in a close environment like a school, and you have basically created a disease factory.

Further, some children cannot be vaccinated for medical reasons. They may have a chronic illness that makes their immune systems too weak to handle the vaccine, or they have an intolerance to vaccines. For these children, if they want to attend school, their only protection is the community immunity that results from all the more healthy children being vaccinated.  Continue Reading »

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May 09 2017

More Anti-Vaccine Pseudoscience

ObukhanychAnti-vaccine nonsense is relentless, and spreads through social media like a measles virus in an upscale private California school. Therefore we need frequent skeptical booster shots.

I will usually decide to take on a topic if I see it spreading or if fellow skeptics aren’t sure what the deception is. A story is sending up red flags, but a more expert eye is needed.

Pretty much every word in this headline is wrong or deceptive: Harvard Study Proves Unvaccinated Children Pose No Risk.

First, there is no study. This is not in any way about some new study or research, but simply an article by an anti-vaccine crank, Tetyana Obukhanych. Further, her connection to Harvard seems tenuous and it’s not even clear what her current academic status is. And most importantly, she uses cherry picked, irrelevant, and incorrect information to make her case.

But she appears to be the new darling of the anti-vaccine movement, so let’s take a deeper look. Continue Reading »

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Feb 16 2017

More Anti-Vaccine Nonsense from Trump and Kennedy

kennedy-deniroWe have an anti-vaccine president. One of my concerns about Trump the candidate was that one of his most consistent positions over the years was blaming vaccines for the alleged autism epidemic (there isn’t one, by the way). Once elected it did not take long for this to manifest as a policy priority. In January Trump met with RFK Jr. to discuss him heading an Orwellian commission on vaccine safety and scientific integrity.

At a recent meeting with educators, Trump continued to express his false belief in a “tremendous increase” in autism:

“Have you seen a big increase in the autism with the children?” Trump asked Jane Quenneville, the principle of a Virginia public school that specializes in special education. Quenneville responded that she had.

Trump continued: “So what’s going on with autism? When you look at the tremendous increase, it’s really such an incredible — it’s really a horrible thing to watch, the tremendous amount of increase. Do you have any idea?”

“The autism?” Really? Continue Reading »

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