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 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 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 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, 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 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 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 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.
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 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 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 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
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 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
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 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 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, 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 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 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 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 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, 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, 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 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, 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 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.