August 25, 2008
As students head back to school this fall (or to school for the first time), parents
around the country are being asked to show evidence that their children have all
of their immunizations up to date. The immunizations that are required vary by age,
and certain areas have populations that are at higher risk for certain illnesses,
so students living in those areas may be asked to have even more immunizations before
entering school for the new year.
For the past few years, vaccines have made the news as a controversial topic. Whether
the concerns are about babies and toddlers getting the MMR vaccine (measles, mumps,
and rubella) or teens and preteens getting vaccinated against HPV (Human papillomavirus),
parents have questions. For those with opinions for or against vaccination, the
reasoning that led them to where they stand is as varied as each individual situation.
Whatever the reason, vaccination rates are dropping in the United States. While
diseases that were once all but forgotten domestically are still rare, they are
on the rise.
"Measles cases in the U.S. are at the highest level in more than a decade,
with nearly half of those involving children whose parents rejected vaccination,
health officials reported Thursday.... The number of cases is still small, just
131, but that's only for the first seven months of the year. There were only
42 cases for all of last year. ... Measles, best known for a red skin rash, is a
potentially deadly, highly infectious virus that spreads through contact with a
sneezing, coughing, infected person. It is no longer endemic to the United States,
but every year cases enter the country through foreign visitors or Americans returning
from abroad. Measles epidemics have exploded in Israel, Switzerland and some other
countries. But high U.S. childhood vaccination rates have prevented major outbreaks
here. In a typical year, only one outbreak occurs in the United States, infecting
perhaps 10 to 20 people. So far this year through July 30 the country has
seen seven outbreaks, including one in Illinois with 30 cases, said Seward, of
the CDC's Division of Viral Diseases."
As the rate of immunization rises, the diseases are virtually eliminated from the
U.S. population. With the diseases out of sight, so are the reminders that caused
the vaccines to be created in the first place.
"Today, vaccine-preventable diseases are at or near record lows. By virtue
of their absence, these diseases are no longer reminders of the benefits of vaccination....
As a result, parents and providers in the United States are more likely to know
someone who has experienced an adverse event following immunization than they are
to know someone who has experienced a reportable vaccine-preventable disease. Thus,
the success of vaccination has led to increased public attention on health risks
associated with vaccines."
With rumors and reminders of the possible side effect in the news, and the diseases
themselves rarely seen, some parents see the vaccine as a bigger threat than the
disease. With that, they think of the children they love, and they decide what they
think is best for their child. By thinking of the vaccine in terms of how it may
affect the life of their child, parents can make different decisions than those
who are concerned about the public health as a whole.
"In the developed world individual rights are given a high value, and antivaccine
campaigners capitalise on the perspective of the individual, whereas public health
perspective is based on the benefits for the community. If, because of a vaccine
programme, the incidence of the disease has become low then the risk of disease
for an individual is low but the risk of adverse effects from the vaccine is unchanged.
Therefore for the individual, protection from disease by 'herd immunity'
may become the safest option because it avoids the risk from the vaccine. On the
other hand, from the public health perspective, avoidance of vaccination is clearly
not in the best interest of public because herd immunity diminishes as coverage
It is only with "herd immunity" that those who are too young or too sick
to be vaccinated can be protected.
Herd immunity: is "a reduction in the probability of infection that is held
to apply to susceptible members of a population in which a significant proportion
of the individuals are immune because the chance of coming in contact with an infected
individual is less."
It is also only when taking into consideration the "herd immunity" that
the decision of one parent to vaccinate (or not vaccinate) their child transforms
from a decision about what is best for "the good of the one" and becomes
a decision about what is best for "the good of the many."
Ask most parents in Western countries, and they will put the health and well being
of their own child above what may or may not happen to anyone else. No one wants
to do something that could hurt their child, and the questions are then raised as
to which decision could potentially hurt the child more. It can be difficult for
parents to sort through all of the information they find and decide what will be
the best decision for their children.
"While the vast majority of American parents vaccinate their children, more
appear to be opting against immunization.... Heightened attention to the heated
vaccine debate has parents on both sides of the fence discussing the issues more
and sometimes finding themselves in awkward or even acrimonious social situations....
Many parents who choose not to vaccinate--often because of fear that autism could
be caused by vaccines (though there's no scientific evidence of a connection),
or they have other philosophical or religious objections--argue that if another
person's child is immunized, what's the problem? Many parents who vaccinate feel
this way too, if they think about the issue at all."
Some consider those who vaccinate to be putting their children at risk. Some consider
those who don't vaccinate to be putting their children at risk. Either way,
it is considered a personal (or family) decision. That said, there are some who
do not consider it personal; they consider it public when the decision of one family
not to vaccinate puts not only themselves, but others, at risk. This is where the
"herd immunity" plays a role, and where the lines between private health
and public health get fuzzy.
"But vaccines aren't an absolute guarantee. Most are 90 percent to 99 percent
effective, according to the American Academy of Pediatrics.... Sara Michalski, 28,
a mother of two unvaccinated children in Colorado Springs, Colo., says most of her
friends do not immunize their kids, either. And beyond her close social circle,
she's reluctant to talk much about it with others because she doesn't want
to get into an argument.... At the same time, Michalski doesn't believe the
decision to not vaccinate her kids is other people's business. 'This is
a private health matter, and not something people are entitled to know about unless
I want to tell them,' she says."
Once again, the bottom line is that parents want to protect their children. For
parents who know that vaccines are not 100% effective, and for those who have children
at home who are too young or too sick to be vaccinated, not being able to rely on
"herd immunity" can be scary.
- "People should not get MMR vaccine who have ever had a life-threatening allergic
reaction to gelatin, the antibiotic neomycin, or to a previous dose of MMR vaccine.
- People who are moderately or severely ill at the time the shot is scheduled should
usually wait until they recover before getting MMR vaccine.
- Pregnant women should wait to get MMR vaccine until after they have given birth.
Women should avoid getting pregnant for 4 weeks after getting MMR vaccine.
- Some people should check with their doctor about whether they should get MMR vaccine,
- Ask your doctor or nurse for more information."
When those who rely on herd immunity are suddenly in a situation where there is
not a high enough percentage of those vaccinated to create this environment, it
can be scary.
"But parents who don't know who's vaccinated and who isn't have their own concerns,
highlighted by the measles outbreak in San Diego earlier this year that resulted
when an unvaccinated 7-year-old boy traveling to Switzerland contracted measles.
The virus spread to 11 other unvaccinated children at both his school and his pediatrician's
office — including a few babies who were too young to receive the measles, mumps
and rubella (MMR) vaccine.... 'From the vaccinating parent perspective, it's
a little infuriating because you don't know who these kids are,' says Brown,
a vaccine proponent and co-author of the book 'Baby 411.' But do others
have the right to know such personal medical information? Should parents inquire
about vaccination status before a play date? Some say that's taking things too far.
For those who have to make the choice between the disease or the vaccine, parents
are deciding for themselves which scares them more.
"The measles, mumps, and rubella (MMR) vaccine is a combination vaccine that
was licensed in 1971 to protect against measles, mumps, and rubella. These diseases
are serious and can be potentially deadly. Each year in the United States, nearly
10 million doses of the vaccine are distributed. In 1998, a study of autistic children
raised the question of a connection between the MMR vaccine and autism. This study
had a number of limitations. ... Other larger studies have found no relationship
between MMR vaccine and autism."
While the focus of this article has been specifically on the MMR vaccine and recent
measles outbreaks as they pertain to herd immunity, this is only one small aspect
of the greater immunization issue, and not all vaccines protect against diseases
where herd immunity is involved.
Tetanus, for example is: "a serious but preventable disease that affects the
body's muscles and nerves. It typically arises from a skin wound that becomes
contaminated by a bacterium called Clostridium tetani, which is often found in soil.
Once the bacteria are in the body, they produce a neurotoxin (a protein that acts
as a poison to the body's nervous system) known as tetanospasmin that causes
muscle spasms. The toxin can travel throughout the body via the bloodstream and
lymph system. As it circulates more widely, the toxin interferes with the normal
activity of nerves throughout the body, leading to generalized muscle spasms. Without
treatment, tetanus can be fatal."
When the disease from which the vaccine is supposed to be protecting a person is
found in the environment, the amount of people who do or do not have the vaccine
within the community does not affect whether or not a person is more or less likely
to catch the disease. In such cases, the lines between public health issues and
private health decisions can be clearer, and in such cases the vaccination issue
can be less controversial.
Questions of the Week:
What do people need to consider when deciding which vaccines to get, and when? What
role do personal risk factors (for disease and for potential side effects to the
vaccine) play when individuals make these decisions? How might whether or not a
person is vaccinated affect their travel plans? How might it affect their social
interactions? What role might the consideration of herd immunity play in these decisions?
In what cases is herd immunity irrelevant?
Please email me with any ideas or suggestions.
Note: Due to increasing amounts of SPAM sent to this account, please include "QOW" in the subject line when sending me email.