Archive for February, 2015

Measles Vaccine (What? Again?)

Much has been made in the past couple of weeks of Senator Rand Paul’s (R-KY) comments about the neurological complications of the measles vaccine.  He recanted his ill-advised comments several days later, but they linger on, and many others have commented on his comments.  Ad nauseam.  Some commentators, in an effort to emphasize the safety of the vaccine and encourage people to get vaccinated or get their children vaccinated, have denied that there have ever been any severe side effects (a scientist would call them ‘adverse reactions’) at all.  Strictly speaking, neither is correct.

The measles vaccine has been out since the early 1970’s in the United States, and since that time a number of adverse reactions have occurred in the days, weeks and months after some people were immunized.  I use that convoluted language to emphasize a point.  Adverse reactions can’t occur until the vaccine is given.  You certainly can’t get a bad reaction to a vaccine before it’s given, can you?  Therefore, timing is important.  And just because a person receives a vaccine and gets a bad reaction, that by itself doesn’t prove that the reaction was caused by the vaccine.  That being said, many reactions to measles vaccine have been reported.  Autism is not one of them.  (Measles vaccine is now given either as a trivalent vaccine along with mumps and rubella, or as a tetravalent vaccine: measles, mumps, rubella, and varicella.).  Most reactions have been mild, such as fever or a mild rash.  Some have been more severe, including seizures, joint pain and stiffness, low platelet count.  Some have been very severe, including long-term seizures, even permanent brain damage.  It is this last point to which Senator Paul was probably referring.

The reason these reactions are related to measles vaccine is, again, timing.  They occurred after the vaccine was given.  That doesn’t prove unequivocally that the reactions were due to the vaccine, but with some reactions, such as fever and a mild rash, the sheer number of cases of these reactions pretty well implicates the vaccine.  But the same can’t be said for the serious reactions.  So few cases of seizures and permanent brain damage have been reported we just can’t ascribe them to the vaccine.  There’s not enough data.

The only way to really prove that severe brain damage has been caused by the vaccine would be to take hundreds of thousands of children and divide them into two groups.  That is, it would have to be done as a double-blind trial.  One group would receive the vaccine, the other a placebo.  Then we’d look for adverse reactions.  They should occur only in the vaccinated.  But such a trial would certainly be time consuming, expensive, unnecessary, and most important of all, grossly unethical.  So, all we do is report adverse reactions when they occur.

The reduction in number of cases of measles after the introduction of the measles vaccine certainly justifies the continued use of the vaccine.  Measles is not just a bad cold with a rash.  The disease itself can cause neurological complications, even death.  The only way we’ll ever be free of the scourge of measles will be when it is eradicated from the earth.  I have no idea what Rand Paul will comment on then.

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Measles Vaccine, Part Two

No, the title of this post doesn’t mean I’ve posted before about the measles vaccine.  In fact, I’ve never said anything about measles or the vaccine in these little essays on WordPress.  What I’m saying here is that this posting is about a second reason for getting the vaccine, if you or your children aren’t presently vaccinated.  The primary reason for getting the vaccine is two-fold: to prevent getting the disease caused by the wild virus, and, by extension, to prevent spreading the disease to others.  It is this main reason that measles and the measles vaccine have been in the news so much lately.  But there is also a second reason to get vaccinated.  This has to do with infants and their mothers.

Before the measles vaccine was developed, measles was a common childhood disease, along with mumps, chickenpox and rubella.  (All of those also have vaccines, by the way.)  There were millions of cases of measles every year in the US.  There were very few deaths due to measles, but what is most important for this discussion is that girls and women who got the disease also got a life-long immunity to it.  When these women got pregnant, they passed some of their immunity to the developing fetus, and this immunity helped keep the newborn from contracting the disease for a short time after birth.  An infant’s immune system is not fully developed until about nine to twelve months after birth, and this is why the recommendation is that a child not get his/her first immunizations until he/she is about one year old.  Well, Mother Nature, in her infinite wisdom, took care of that delay in immune system formation and allowed some of the antibodies that the mother possesses after a natural infection to cross the placenta and circulate in the newborn’s blood.  That way the infant was protected.  Well, to a certain extant.  This type of transferred immunity isn’t as good as that after a natural infection, but it is something.

Then, along came the vaccine.  Since the measles vaccine was introduced in the early 1970’s, the number of new cases of measles has dropped drastically.  Now, here in the early twenty-first century, we see very few cases.  But mothers now don’t have that immunity induced by a case of the measles, so they don’t pass it along to their children.  Now we’re beginning to see cases of measles in children under one year old.  And these cases can be severe.  When the child had transferred immunity, if he/she did get infected, the disease was frequently milder.

So now we have a rather un-natural situation.  The vaccine reduced the disease, but it left young women with little or no immunity.  So, it is incumbent on all of us to get the vaccine to help prevent infections that might be transferred to a totally unprotected newborn.  Young women who expect to become pregnant soon are advised to get the vaccine, even if they had the vaccine as a child.  But this is more to help prevent them from transmitting the virus to their newborns, not to boost their immunity.  Vaccinated mothers probably don’t transfer much immunity to their fetus, at least not as much as a natural infection would.

The only way out of this situation is to eradicate the disease from the face of the earth, as has been done with smallpox.  Measles is a good candidate for eradication, too.  Only in that situation can a young mother be sure her infant won’t get measles.  For whatever reason.

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Historic versus Historical

 

I was at Chaco Culture National Historical Park several years ago to help the Sierra Club do some routine maintenance around the Park.  Things that the regular staff doesn’t get to.  (Clean out brush, make some signs, clean debris out of some of the historic remains, etc.)  After I left, I got to wondering about the name.  The Park is a part of the National Park Service and so is run by the Interior Department.  But the point about the name I was curious about was the word “Historical.”   Shouldn’t it be “Historic”?  After all, the remains of the buildings built by the Chacoan People are certainly historic.  They’re a part of the history of the land that was eventually incorporated into the nation we now call the United States.  They were built between 800 and 1000 AD, and the US made them a part of a National Park that takes care of them and studies them to learn more about the people who built them.  Certainly a reasonable thing to do.  So I looked up the two words in the dictionary.

“Historic” means “famous or important in history.”  “Historical,” though, means “of, relating to, or having the characteristics of history.”  Also “based on history,” or “famous in history.”  I can identify with the definition of “historic,” but the definition of “historical” left me unsatisfied.  The two definitions are almost the same.  Is there a real difference, and if so, what is it?

Actually, I believe the National Park Service got it right.  It should be Chaco Culture National Historical Park.  The reason for using that word is that it’s not the Park itself that’s historic, it’s what’s in the Park that is.  The Park was created well after the buildings it preserves were constructed.  We make a distinction between what’s historic on the one hand, and what preserves history on the other.  For example, the Declaration of Independence is an historic document, but the National Archives where it is stored and displayed is not an historic building (it’s not that old).  The Archives is an historical building because it preserves the document.  Likewise, Chaco Culture Park preserves the remnants of the Chaco Culture.  On the other hand, Independence Hall in Philadelphia is an historic building because history was made there.  Thus, “historic” means “important in history,” where “historical” has to do with preserving or studying or maintaining history.

Another example: the Lincoln Memorial in Washington, DC is not an historic building.  It was put up well after Abraham Lincoln died, and serves to commemorate the life of the 16th President.  It could be considered an historical building.  So I believe a real difference exists between the two words and we should be careful to use them correctly.  As the Park Service did.

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