Tag: antigens

Are There Any Long-Term Studies On Vaccine Safety?

Vaccines are evaluated for safety in studies when they get approved.

Is that enough?

“I would like to see us do more long-term safety research studies on these large groups of children, so then we can determine that they are safe in the long-term.”

Bob Sears

Apparently not for everyone…

Are There Any Long-Term Studies On Vaccine Safety?

Of course, vaccines continue to be evaluated for safety after they approved, using passive and active vaccine safety systems and long-term post-marketing safety studies.

“We learn about a vaccine’s safety during clinical trials before it is licensed, and monitor it continually as millions of doses are administered after it is licensed. We also know there is not a plausible biologic reason to believe vaccines would cause any serious long-term effects. Based on more than 50 years of experience with vaccines, we can say that the likelihood that a vaccine will cause unanticipated long-term problems is extremely low.”

Parents’ Guide to Childhood Immunizations

These long term studies on vaccine safety have looked at:

Have you heard about these studies before?

When they talk about SV40, do anti-vaccine folks mention this long-term study?
When they talk about SV40, do anti-vaccine folks mention this long-term study?

Probably not.

Anti-vaccine folks either aren’t aware of, or just don’t want you to know about these types of long-term studies.

It’s easier to scare you away from vaccinating and protecting your kids if they make you believe that vaccines aren’t tested together, aren’t tested with placebos, aren’t tested vs unvaccinated kids, and aren’t tested for long periods of time.

They are!

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Are the Tdap and DTaP Vaccines the Same Thing?

You have probably already figured out the Tdap and DTaP aren’t the same vaccine, after all, if they were, why would they have different names, right?

Are the Tdap and DTaP Vaccines the Same Thing?

I bet you don’t know the difference between the two vaccines though.

Yes, they both are both combination vaccines that protect against diphtheria, tetanus, and pertussis.

The difference is that one (DTaP) is used as the primary series for infants and younger children (age 6 years and under) and the other (Tdap) is given to older children (age 7 years and above), teens, and adults.

Okay, that’s not the only difference.

The DTaP vaccine actually contains more diphtheria and pertussis antigens than Tdap, which is why it has the capital “D” and “P” in its name. The amount of tetanus toxoid antigens are about the same in both vaccines.

So Tdap contains the same amount of tetanus toxoid, plus a reduced amount of diphtheria and acellular pertussis antigens, as compared to DTaP.

While you would think that older children and adults would get the vaccine with the higher amount of antigens, since they are bigger, that’s not how this works. Vaccines typically start working at the injection site, so body size isn’t a key factor in determining the amount of ingredients.

As a booster dose of vaccine, the lower amount of antigens works just fine and helps reduce the risk of side effects from repeated doses that you might get with higher antigen counts.

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Where are the Saline Placebos?

Remember when anti-vaccine folks used to say that there were no double-blind, placebo-controlled randomized clinical trials for vaccines?

What happened once they realized that there actually were?

They moved the goal posts…

Where are the Saline Placebos?

Okay, they said.

So you have done double-blind, placebo-controlled randomized clinical trials when testing vaccines, but what placebo did you use?

Was it a pure saline placebo?

“Placebo Control – A comparator in a vaccine trial that does not include the antigen under study. In studies of monovalent vaccines this may be an inert placebo (e.g. saline solution or the vehicle of the vaccine), or an antigenically different vaccine. In combined vaccines, this may be a control arm in which the component of the vaccine being studied is lacking.”

WHO on the Guidelines on clinical evaluation of vaccines: regulatory expectations

Although no guidelines actually call for using a pure saline placebo, that’s all anti-vaccine folks will accept these days.

Why?

That’s their MO – or method of operation.

When one theory or myth gets squashed – they move to another.

They move the goalposts.

It doesn’t matter that there are often ethical and logistical problems with using pure saline placebos, that’s all they want to hear about it.

That they wouldn’t be satisfied and start vaccinating their kids if all vaccine studies started to use saline placebos should be evident when you consider that many vaccine studies have already used saline placebos!

There are many more vaccine studies that have used saline placebos and like other vaccine studies, have found vaccines to be safe and effective.

But how do you know that they used a real saline placebo and not some kind of saline solution with other stuff in it?

If it isn’t clear to you in the methods section of the study, go to the source – the original clinical trials record and it will be listed there.

What are you going to be worried about now?

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What Is a Vaccine?

You know what a vaccine is, right?

The word vaccine comes from the vaccinia virus that was in the original smallpox vaccine.
The word vaccine comes from the vaccinia virus that was in the original smallpox vaccine.

The flu shot you get each year is a vaccine.

Vaccine: A product that stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease. Vaccines are usually administered through needle injections, but can also be administered by mouth or sprayed into the nose.

Immunization: The Basics

The smallpox shot that Edward Jenner developed was a vaccine.

Vaccine Definitions

While that is an easy enough definition to understand, that there are many different types of vaccines does make it a little more complicated.

There are:

  • Live-attenuated vaccines – made from a weakened or attenuated form of a virus or bacteria
  • Inactivated vaccines – made from a killed form of virus or bacteria
  • Subunit, recombinant, polysaccharide, and conjugate vaccines – made from only specific pieces of a virus or bacteria
  • Toxoid vaccines – made to target a toxin that a bacteria makes and not the bacteria itself

And of course all of these types of vaccines work to produce immunity to specific diseases – vaccination.

Immunization: A process by which a person becomes protected against a disease through vaccination. This term is often used interchangeably with vaccination or inoculation.

Immunization: The Basics

What other definitions are important to know when you talk about vaccines?

  • active immunity – immunity that you get from having a disease (natural immunity) or getting a vaccine and making antibodies
  • adjuvant – a substance that helps boost your body’s immune response to a vaccine so that you can use a minimum amount of antigen, reducing side effects
  • antibodies – protective proteins that you make against antigens
  • antigens – specific substances (can be part of a virus or bacteria) that trigger an immune response
  • attenuation – a virus or bacteria that is made less potent, so that it can produce an immune response without causing disease
  • elimination – getting rid of a disease in a specific area
  • endemic – the baseline level of disease in an area
  • eradication – getting rid of a disease everywhere (smallpox)
  • epidemic – an increase in the number of cases of a disease over a large geographic area
  • herd immunity – when enough people in a community are protected and have immunity, so that disease is unlikely to spread
  • immunity – protection against a disease
  • incubation period – how long it takes to develop symptoms after you are exposed to a disease
  • outbreak – an increase in the number of cases of a disease over a small geographic area
  • pandemic – an increase in the number of cases of a disease over several countries or continents
  • passive immunity – temporary immunity that you get after being given antibodies, either via a shot of immunoglobulin or a mother’s antibodies are transferred to her baby through her placenta
  • placebo – classically defined as “a comparator in a vaccine trial that does not include the antigen under study”
  • quarantine – isolating someone so that they don’t get others sick
  • titer – an antibody count that can often be used to predict immunity

Got all of that?

So what about variolation, the process that was used before Jenner developed his smallpox vaccine? Was that also a vaccine?

It did produce immunity to smallpox, which is the basic definition of a vaccine, but still, variolation is typically concerned an immunization technique and not a vaccine.

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