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