April 14, 2021 • 9 mins
Herd immunity can help keep a population healthier, but achieving it can be difficult. Learn about vaccines and vaccination reluctance in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/life/cellular-microscopic/herd-immunity.htm
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:01):
Welcome to brain Stuff, a production of I Heart Radio,
Hey brain Stuff, Lauren vogebam Here. Keeping populations of a
community free from viral disease rests in part on the
success of herd immunity. Herd immunity rests on the principle
of safety and numbers. If more people are immune to
(00:22):
a certain virus, either through vaccination or through already having
had the disease, then more people in the population, even
if they themselves aren't immune, are protected from the disease.
To illustrate this point, let's think about the bowling alleys
that we're all varyingly aching to return to. Pretend this
is twenty nineteen and we're packed in for hours, not
(00:44):
a care in the world besides our frame score and
access to pizza. Let's say a guy in the first
lane is there despite having that season's variant of influenza,
and he passes it along to a woman in the
second lane. If that woman and immune to that variant
of influenza, then the disease will likely continue its path
lane by lane until every person in the bowling alley
(01:07):
is infected. But if that woman is immune, then the
disease could well stop with her because the virus has
nowhere else to go. Assuming that the guy in our
example didn't have contact with anyone else, by her immunity,
she protected all the people on subsequent lanes, even if
they didn't get a flu shot that year. Sounds simple, right, Well,
(01:31):
it's not that simple. For many of us, chickenpox was
a routine part of childhood, a minor annoyance but rarely
life threatening. For that reason, a chickenpox vaccine was met
with some skepticism when it was introduced, and still there
was a push in the United States to get children vaccinated,
and studies have shown that the effort had a tremendous
(01:52):
impact on the disease and the costs associated with it,
and chickenpox hospitalizations dropped by a massive scent as of
twelve compared with the pre vaccine period. During the period
of two thousand six to twelve, when a second dose
became recommended, the hospitalization rate declined by another thirty eight percent,
alleviating more costs all around. Not only does a push
(02:17):
for a chicken pox vaccine protect child and their classmates,
you can also protect grandparents who may not have had
chicken pox. Protecting the elderly is also the idea behind
another vaccination that many of us line up for every winter,
the flu shot. Between twelve thousand and sixty one thousand
Americans have died each year of the flu since of
(02:38):
those of flu related deaths and fifty of hospitalizations are
people over the age of sixty five. While the elderly
are encouraged to get a flu shot, it's actually more
effective if the herd around them is vaccinated, including caretakers
and visitors that might include Germany grandchildren. Oh, let's consider polio.
(03:01):
The success of the polio vaccine demonstrated the benefits of
using immunization to protect a population, and her immunity can
be achieved for a whole host of diseases beyond chicken
pox and the flu, including measles, mumps, and smallpox. And
while the term herd immunity seems to imply that the
whole herd should be vaccinated, it actually means that the
(03:23):
whole herd is protected if a certain percentage is immunized.
Mathematical models can be used to determine exactly what percentage
of the population needs to be vaccinated to prevent a
given communicable disease. For example, if approximately of a population
is vaccinated against polio, then her immunity is achieved, but
(03:45):
measles is more contagious than polio of a population needs
to be vaccinated for her immunity to be achieved. There However,
just because her immunity is achieved doesn't mean it's completely
fool proof. Vaccines themselves aren't a hundred percent effective, and
diseases can still strike those not immune to them. In
(04:07):
some instances, an immunization is only effective for a few years,
so the protection may have worn off a majority of
the herd at the time of an outbreak. The childhood
vaccinations may only delay the age at which outbreaks occur.
For example, if a pregnant person contracts the measles, they
in their unworn baby face far more complications than a
(04:27):
child who endures the disease. So if vaccines don't work
or just put off a mass outbreak in the herd,
do we even need them at all? Some people don't
think a shot in the arm is worth the good
of the herd. If the word vaccine strikes fear instead
of hope in your heart, then you likely came of
(04:49):
age not in a time dominated by worries about polio,
but in a time when vaccines make news because of
side effects ranging from mild irritation to death. The most
notable example is probably the debate regarding the claim, which
is not supported by any scientific studies, that an ingredient
in certain childhood vaccines may have led to an increase
(05:09):
in autism. These days, in spite of the lack of
scientific evidence to support a link between vaccines and autism
and the fact that the ingredient is no longer used
in most childhood vaccines, some people still have serious doubts
about whether it's worth protecting herd immunity at the cost
of exposing children to these supposed risks. That means that
(05:32):
levels of vaccinations have dropped, particularly in certain parts of
the United States where exemption from vaccines is granted for religious, philosophical,
or personal reasons. But socioeconomic factors appear to play a
bigger role than religious or personal reasons for lack of vaccination.
C DC summary noted that the percentage of children without
(05:53):
any vaccines has risen to one point three percent four
kids born in compared with the two one survey that
found just zero point three percent of children aged nineteen
to thirty five months hadn't been vaccinated at all. The
summary found this was significantly more common among children who
were uninsured, Medicaid ensured, or who lived in rural areas,
(06:15):
as seventeen point two percent of unvaccinated children were uninsured,
for instance, compared with just two point eight percent of
all children. A study by the Health Testing Centers using
CDC data found that twenty seven states had kindergarten populations
with vaccination rates below state targets. As parents who forego
(06:37):
vaccinations may believe that they can rely on herd immunity
to protect their children, children who aren't immunized may be
protected by the children that did get vaccinations. However, as
parental fears caused vaccination rates to drop, the safety of
the herd, particularly its weakest members, can become compromised. Some
(06:57):
children aren't able to be vaccinated because of health reasons
and truly need to rely on the herd for their immunity.
Of course, just because science has come a long way
and addressing major illnesses doesn't mean that large scale outbreaks
can't happen anymore. The COVID nineteen pandemic has left healthcare
experts and world leaders grappling with what the best course
(07:20):
of action is to combat the virus for the long term.
But while herd immunity is effective for some illnesses, whether
it's a viable solution for COVID nineteen remains to be seen.
Evidence to date suggests that herd immunity is likely not
a realistic option for COVID nineteen. For example, the country
of Sweden opted to shun social restrictions adopted by much
(07:42):
of the rest of the world in favor of offering
optional guidelines to citizens and relying on her immunity. Initial
reports from April indicated that it hadn't worked out so well, however,
with Sweden experiencing a COVID nineteen death rate of eight
percent compared with na bring, Denmark fourcent, and Norway under two,
(08:04):
both of which enacted greater restrictions from the get go.
Although the research into and school of thought around COVID
nineteen changes practically day by day, it stands to reason
that herd immunity might never be the miracle solution that
everyone's been praying for. And this is because the virus
that causes COVID nineteen is probably like other coronaviruses and influenza,
(08:28):
and that it will mutate over time. When it mutates,
any antibodies from a prior infection will provide little, if
any protection. So people who came down with COVID nineteen
might be protected for a few months to a year
or two, but lifelong immunity is decidedly unlikely. And don't
(08:49):
forget that COVID nineteen is about ten times more deadly
than the flu, and even higher among vulnerable populations like
the elderly. As a result, it's important that every one
who's able to receive a COVID nineteen vaccine now sign
up to receive one, and why our fingers are crossed.
The vaccine rollout will continue at the safest possible pace,
(09:10):
and the other treatments will be developed soon. There's a
possibility that such vaccines will become like flu vaccines, available
every year to protect you and the herd from new variants.
Today's episode is based on the article how does herd
immunity keep a country safe from diseases? On how stuff
(09:32):
works dot com written by Leah Hoyt and Molly Edmonds.
Brain Stuff is production of I Heart Radio in partnership
with how stuff works dot Com and It is produced
by Tyler Klein. Four more podcasts My Heart Radio, visit
the iHeart Radio app, Apple podcasts, or wherever you listen
to your favorite shows.
Welcome to brain Stuff, a production of I Heart Radio,
Hey brain Stuff, Lauren vogebam Here. Keeping populations of a
community free from viral disease rests in part on the
success of herd immunity. Herd immunity rests on the principle
of safety and numbers. If more people are immune to
(00:22):
a certain virus, either through vaccination or through already having
had the disease, then more people in the population, even
if they themselves aren't immune, are protected from the disease.
To illustrate this point, let's think about the bowling alleys
that we're all varyingly aching to return to. Pretend this
is twenty nineteen and we're packed in for hours, not
(00:44):
a care in the world besides our frame score and
access to pizza. Let's say a guy in the first
lane is there despite having that season's variant of influenza,
and he passes it along to a woman in the
second lane. If that woman and immune to that variant
of influenza, then the disease will likely continue its path
lane by lane until every person in the bowling alley
(01:07):
is infected. But if that woman is immune, then the
disease could well stop with her because the virus has
nowhere else to go. Assuming that the guy in our
example didn't have contact with anyone else, by her immunity,
she protected all the people on subsequent lanes, even if
they didn't get a flu shot that year. Sounds simple, right, Well,
(01:31):
it's not that simple. For many of us, chickenpox was
a routine part of childhood, a minor annoyance but rarely
life threatening. For that reason, a chickenpox vaccine was met
with some skepticism when it was introduced, and still there
was a push in the United States to get children vaccinated,
and studies have shown that the effort had a tremendous
(01:52):
impact on the disease and the costs associated with it,
and chickenpox hospitalizations dropped by a massive scent as of
twelve compared with the pre vaccine period. During the period
of two thousand six to twelve, when a second dose
became recommended, the hospitalization rate declined by another thirty eight percent,
alleviating more costs all around. Not only does a push
(02:17):
for a chicken pox vaccine protect child and their classmates,
you can also protect grandparents who may not have had
chicken pox. Protecting the elderly is also the idea behind
another vaccination that many of us line up for every winter,
the flu shot. Between twelve thousand and sixty one thousand
Americans have died each year of the flu since of
(02:38):
those of flu related deaths and fifty of hospitalizations are
people over the age of sixty five. While the elderly
are encouraged to get a flu shot, it's actually more
effective if the herd around them is vaccinated, including caretakers
and visitors that might include Germany grandchildren. Oh, let's consider polio.
(03:01):
The success of the polio vaccine demonstrated the benefits of
using immunization to protect a population, and her immunity can
be achieved for a whole host of diseases beyond chicken
pox and the flu, including measles, mumps, and smallpox. And
while the term herd immunity seems to imply that the
whole herd should be vaccinated, it actually means that the
(03:23):
whole herd is protected if a certain percentage is immunized.
Mathematical models can be used to determine exactly what percentage
of the population needs to be vaccinated to prevent a
given communicable disease. For example, if approximately of a population
is vaccinated against polio, then her immunity is achieved, but
(03:45):
measles is more contagious than polio of a population needs
to be vaccinated for her immunity to be achieved. There However,
just because her immunity is achieved doesn't mean it's completely
fool proof. Vaccines themselves aren't a hundred percent effective, and
diseases can still strike those not immune to them. In
(04:07):
some instances, an immunization is only effective for a few years,
so the protection may have worn off a majority of
the herd at the time of an outbreak. The childhood
vaccinations may only delay the age at which outbreaks occur.
For example, if a pregnant person contracts the measles, they
in their unworn baby face far more complications than a
(04:27):
child who endures the disease. So if vaccines don't work
or just put off a mass outbreak in the herd,
do we even need them at all? Some people don't
think a shot in the arm is worth the good
of the herd. If the word vaccine strikes fear instead
of hope in your heart, then you likely came of
(04:49):
age not in a time dominated by worries about polio,
but in a time when vaccines make news because of
side effects ranging from mild irritation to death. The most
notable example is probably the debate regarding the claim, which
is not supported by any scientific studies, that an ingredient
in certain childhood vaccines may have led to an increase
(05:09):
in autism. These days, in spite of the lack of
scientific evidence to support a link between vaccines and autism
and the fact that the ingredient is no longer used
in most childhood vaccines, some people still have serious doubts
about whether it's worth protecting herd immunity at the cost
of exposing children to these supposed risks. That means that
(05:32):
levels of vaccinations have dropped, particularly in certain parts of
the United States where exemption from vaccines is granted for religious, philosophical,
or personal reasons. But socioeconomic factors appear to play a
bigger role than religious or personal reasons for lack of vaccination.
C DC summary noted that the percentage of children without
(05:53):
any vaccines has risen to one point three percent four
kids born in compared with the two one survey that
found just zero point three percent of children aged nineteen
to thirty five months hadn't been vaccinated at all. The
summary found this was significantly more common among children who
were uninsured, Medicaid ensured, or who lived in rural areas,
(06:15):
as seventeen point two percent of unvaccinated children were uninsured,
for instance, compared with just two point eight percent of
all children. A study by the Health Testing Centers using
CDC data found that twenty seven states had kindergarten populations
with vaccination rates below state targets. As parents who forego
(06:37):
vaccinations may believe that they can rely on herd immunity
to protect their children, children who aren't immunized may be
protected by the children that did get vaccinations. However, as
parental fears caused vaccination rates to drop, the safety of
the herd, particularly its weakest members, can become compromised. Some
(06:57):
children aren't able to be vaccinated because of health reasons
and truly need to rely on the herd for their immunity.
Of course, just because science has come a long way
and addressing major illnesses doesn't mean that large scale outbreaks
can't happen anymore. The COVID nineteen pandemic has left healthcare
experts and world leaders grappling with what the best course
(07:20):
of action is to combat the virus for the long term.
But while herd immunity is effective for some illnesses, whether
it's a viable solution for COVID nineteen remains to be seen.
Evidence to date suggests that herd immunity is likely not
a realistic option for COVID nineteen. For example, the country
of Sweden opted to shun social restrictions adopted by much
(07:42):
of the rest of the world in favor of offering
optional guidelines to citizens and relying on her immunity. Initial
reports from April indicated that it hadn't worked out so well, however,
with Sweden experiencing a COVID nineteen death rate of eight
percent compared with na bring, Denmark fourcent, and Norway under two,
(08:04):
both of which enacted greater restrictions from the get go.
Although the research into and school of thought around COVID
nineteen changes practically day by day, it stands to reason
that herd immunity might never be the miracle solution that
everyone's been praying for. And this is because the virus
that causes COVID nineteen is probably like other coronaviruses and influenza,
(08:28):
and that it will mutate over time. When it mutates,
any antibodies from a prior infection will provide little, if
any protection. So people who came down with COVID nineteen
might be protected for a few months to a year
or two, but lifelong immunity is decidedly unlikely. And don't
(08:49):
forget that COVID nineteen is about ten times more deadly
than the flu, and even higher among vulnerable populations like
the elderly. As a result, it's important that every one
who's able to receive a COVID nineteen vaccine now sign
up to receive one, and why our fingers are crossed.
The vaccine rollout will continue at the safest possible pace,
(09:10):
and the other treatments will be developed soon. There's a
possibility that such vaccines will become like flu vaccines, available
every year to protect you and the herd from new variants.
Today's episode is based on the article how does herd
immunity keep a country safe from diseases? On how stuff
(09:32):
works dot com written by Leah Hoyt and Molly Edmonds.
Brain Stuff is production of I Heart Radio in partnership
with how stuff works dot Com and It is produced
by Tyler Klein. Four more podcasts My Heart Radio, visit
the iHeart Radio app, Apple podcasts, or wherever you listen
to your favorite shows.
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