Tag: outbreaks

Is the Anti-Vaccine Movement Growing?

Boston Reverend Cotton Mather  actively promoted smallpox inoculation during a local epidemic.
Boston Reverend Cotton Mather actively promoted smallpox inoculation during a local epidemic.

We often have to remind people that the anti-vaccine movement didn’t start with Bob Sears, or Jenny McCarthy, or even with Andy Wakefield.

Did you know that the Reverend Cotton Mather’s house was bombed in Boston in 1721? Well, someone through a bomb through his window. Fortunately, it didn’t go off.

That’s 77 years before Jenner developed his smallpox vaccine!

What was Mather doing?

He had started a smallpox variolation program. He was trying to protect people in Boston from smallpox during one of the most deadly epidemics of the time.

So essentially, the anti-vaccine movement started before we even had real vaccines…

Is the Anti-Vaccine Movement Growing?

You see reports of more and more outbreaks of vaccine-preventable diseases, hear about new vaccine laws and mandates, and depending on who your friends are, may see a lot of anti-vaccine articles and vaccine injury stories getting shared on Facebook.

You have probably even heard about pediatricians firing families who refuse to vaccinate their kids.

So what’s the story?

Is the anti-vaccine movement growing?

Is there a growing resistance among parents to getting their kids vaccinated?

“Parents are taking back the truth. It is my expectation that this crack in the dam will serve to sound an alarm. To wake women up. To show them that they have relinquished their maternal wisdom, and that it is time to wrest it back.”

Kelly Brogan, MD

Is the world finally “waking up to the dangers of vaccines,” like many anti-vaccine experts have been claiming for years and years?

The Anti-Vaccine Movement is not Growing

Many people will likely tell you that the anti-vaccine is in fact growing.

You can read it in their headlines:

  • The worrying rise of the anti-vaccination movement
  • Will 2017 be the year the anti-vaccination movement goes mainstream?
  • Pediatricians calling anti-vaccine movement a growing problem
  • There’s Good Evidence That The Anti-Vaccine Movement Is Growing
  • I was skeptical that the anti-vaccine movement was gaining traction. Not anymore.

But the anti-vaccine movement is not necessarily growing.

The overwhelming majority of parents and adults are fully vaccinated.

What we do have is a very vocal minority of people who do their best to push misinformation and conspiracy theories about vaccines and vaccine dangers, and not surprisingly, they have some new ways to do it. Unfortunately, they use their anti-vaccine talking points to scare vaccine hesitant parents and those who might now be on the fence about vaccines to sometimes delay or skip some vaccines.

Most parents do their research though, don’t jump on the anti-vaccine bandwagon, and know that vaccines work, vaccines are safe, and vaccines are necessary.

The Anti-Vaccine Movement is Changing

A lot about the anti-vaccine movement hasn’t changed over the last 100 plus years.

Many early critics of vaccines were alternative medicine providers, including homeopaths and chiropractors, just like we see today. And like they do today, they argued that vaccines didn’t work, vaccines were dangerous, and that vaccines weren’t even necessary.

alicia-silverstone

The big difference?

Unlike when Lora Little, at the end of the 19th century, had to travel around the country to distribute her anti-vaccine pamphlet, Crimes of the Cowpox Ring, anti-vaccine folks can now just tweet or post messages on Facebook. It is also relatively easy to self-publish an anti-vaccine book and sell it on Amazon, put up your own anti-vaccine website, post videos on YouTube, or even make movies.

“Whatever you think about Andrew Wakefield, the real villains of the MMR scandal are the media.”

Ben Goldacre on The MMR story that wasn’t

Fortunately, all of that is balanced by something they don’t have anymore.

No, it’s not science. That was never on their side.

It’s that the media has caught on to the damage they were doing and isn’t as likely to push vaccine scare stories anymore.

Explaining the Popularity of the Anti-Vaccine Movement

The anti-vaccine movement has always been around and they are likely not going anywhere, whether or not they are growing.

Looking at the history of the anti-vaccine movement, it is clear that they have their ups and downs, times when they are more or less popular, but they are always there.

“By the 1930s… with the improvements in medical practice and the popular acceptance of the state and federal governments’ role in public health, the anti-vaccinationists slowly faded from view, and the movement collapsed.”

Martin Kaufman The American Anti-Vaccinations and Their Arguments

Why so many ups and downs?

As more people are vaccinated and diseases disappear, they forget how bad those diseases are, skip or delay getting their vaccines, and trigger outbreaks.
As more people are vaccinated and diseases disappear, they forget how bad those diseases are, skip or delay getting their vaccines, and trigger outbreaks. Chart by WHO

It is easily explained once you understand the evolution of our immunization programs, which generally occurs in five stages:

  1. pre-vaccine era or stage
  2. increasing coverage stage – as more and more people get vaccinated and protected, you pass a crossover point, where people begin to forget just how bad the diseases really were, and you start to hear stories about “mild measles” and about how polio wasn’t that bad (it usually wasn’t if you didn’t get paralytic polio…)
  3. loss of confidence stage – although vaccine side effects are about the same as they always were, they become a much bigger focus because you don’t see any of the mortality or morbidity from the diseases the vaccines are preventing. It is at this point that the anti-vaccine movement is able to be the most effective.
  4. resumption of confidence stage – after the loss of confidence in stage three leads to a drop in vaccine coverage and more outbreaks of a vaccine-preventable disease, not surprisingly, more people understand that vaccines are in fact necessary and they get vaccinated again. It is at this point that the anti-vaccine movement is the least effective, as we saw after outbreaks of pertussis in the UK in the 1970s and measles more recently. You also see it when there is a report of an outbreak of meningococcal disease on a college campus or a child dying of the flu on the local news, etc.
  5. eradication stage – until we get here, like we did when smallpox was eradicated, the anti-vaccine movement is able to cycle through stages two to four, with ups and downs in their popularity,

So the anti-vaccine movement is able to grow when they have the easiest time convincing you that the risks of vaccines (which are very small) are worse than the risks of the diseases they prevent (which are only small now, in most cases, because we vaccinate to keep these diseases away, but were life-threatening in the pre-vaccine era).

“As vaccine use increases and the incidence of vaccine-preventable diseases is reduced, vaccine-related adverse events become more prominent in vaccination decisions. Even unfounded safety concerns can lead to decreased vaccine acceptance and resurgence of vaccine-preventable diseases, as occurred in the 1970s and 1980s as a public reaction to allegations that the whole-cell pertussis vaccine caused encephalopathy and brain damage. Recent outbreaks of measles, mumps, and pertussis in the United States are important reminders of how immunization delays and refusals can result in resurgences of vaccine-preventable diseases.”

Paul Offit, MD on Vaccine Safety

Fortunately, most parents don’t buy into the propaganda of the anti-vaccine movement and don’t wait for an outbreak to get their kids vaccinated and protected. They understand that you can wait too long.

The bottom line – except for pockets of susceptibles and clusters of unvaccinated kids and adults, most people are vaccinated. If the anti-vaccine does grow, it eventually gets pulled back as more kids get sick.

What to Know about the Growing Anti-Vaccine Movement

Although they may have an easier time reaching more people on Twitter, Facebook, YouTube, and with Amazon, the overwhelming majority of parents vaccinate their kids and aren’t influenced by what some people think is a growing anti-vaccine movement.

More on the Growing Anti-Vaccine Movement

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Hiding in the Herd

The term herd immunity has been used for almost 100 years, since about 1923.

Other terms relating to herd immunity, like ‘hiding in the herd’ and ‘free-riding’ have come into use more recently.

Hiding in the Herd

Some people can get away with hiding in the herd.

Actually, they depend on it.

“Herd immunity is present in a community when such a high percentage of its members have been immunized from a particular disease that the disease cannot gain a foothold in the community. Thus, achieving and maintaining herd immunity protects not only those who have been vaccinated, but also those with compromised or weak immune systems, such as the elderly, babies, and those afflicted with HIV.”

Anthony Ciolli on Mandatory School Vaccinations: The Role of Tort Law

That’s because we don’t need 100% of people to be vaccinated and protected for herd immunity to work.

Many children with cancer and other medical conditions benefit from herd immunity.
Many children with cancer and other medical conditions benefit from herd immunity. (CC BY 2.0)

So people who are too young to be vaccinated or fully vaccinated, people who can’t be vaccinated because they were born with an immunodeficiency or get cancer and are on chemotherapy and other true medical exemptions, and even people who are vaccinated but their vaccine didn’t work, can still hope to be protected from vaccine preventable diseases because everyone around them is vaccinated.

These people still get the benefits of herd immunity. Even though they are unvaccinated and susceptible to getting a disease, they probably won’t, because most others in the herd are vaccinated and protected.

But it is not just those people with medical exemptions who try and hide in the herd.

“These numbers have led the National Vaccine Advisory Committee to conclude that religious and philosophical exemptions do not pose a threat to public health.”

T May on Free-riding, fairness and the rights of minority groups in exemption from mandatory childhood vaccination

And that was okay too for a while. It wasn’t that long ago that “free-riding” by those using philosophical or religious exemptions wasn’t a problem, because their numbers were small and herd immunity rates could still be maintained.

Can You Hide in the Herd?

Hiding in the herd can’t work for everyone though.

Surprisingly, Dr. Bob explains that well in his vaccine book that scares parents about toxins in vaccines, while reassuring them that it is okay to space out their child’s vaccines.

“I also warn them not to share their fears with their neighbors, because if too many people avoid the MMR, we’ll likely see the diseases increase significantly.”

Dr. Bob Sears in The Vaccine Book

Basically, if too many people are trying to hide in the herd and have skipped their vaccines, then we have a breakdown in herd immunity and we start to see the return of many vaccine-preventable diseases.

These aren’t people who can’t be vaccinated though.

They are people who refuse to be vaccinated and intentionally don’t vaccinate their kids.

“In other words, hide in the herd, but do not tell the herd you’re hiding; otherwise, outbreaks will ensue. Sears’ advice was prescient. Recent outbreaks of measles in 15 states, caused by an erosion of herd immunity in communities where parents had chosen not to vaccinate their children, were the largest in the United States since 1996.”

Dr. Paul Offit on The Problem With Dr Bob’s Alternative Vaccine Schedule

And that seems to be exactly what happened as more and more parents have walked into their pediatrician’s offices with a copy of Dr. Bob’s Alternative Vaccine Schedule.

While he predicted that it would “increase vaccination rates in our country,” as most others knew,  they went down instead, and we continue to see more and more clusters of unvaccinated children.

Of course, Dr. Bob didn’t create the modern antivaccine-movement, but the bandwagoning effect he and other “thought influencers in the anti-vaccine movement” have on parents isn’t hard to see. Parents get scared by their anti-vaccine talking points and they go on to scare other parents into not vaccinating and protecting their own kids.

Tragically, the consequences of all of this was predictable too.

“If more parents insist on Sears’ vaccine schedules, then fewer children will be protected, with the inevitable consequence of continued or worsening outbreaks of vaccine-preventable diseases.”

Dr. Paul Offit on The Problem With Dr Bob’s Alternative Vaccine Schedule

More outbreaks of vaccine-preventable diseases.

What to Know About Hiding in the Herd

When too many people try and hide in the herd, it makes it hard to maintain necessary levels of herd immunity, which puts everyone, including medically fragile children and adults, at higher risk for getting a vaccine-preventable disease.

More About Hiding in the Herd

New Vaccine Laws and Mandates

Every good vaccine bill doesn't make it into law.
NY passed a law in 2015 that  eliminated religious exemptions to getting vaccines.

California passed a new vaccine law, SB 277, in 2015.

Most states, including California, already had vaccine mandates though. The difference now is that in California, you need a medical exception to attend school if your kids aren’t vaccinated.

With the passage of SB 277, California joined Mississippi and West Virginia as the only states that do not allow either religious or personal belief vaccine exemptions.

They still aren’t forcing anyone to get vaccinated though.

“The term mandate is somewhat misleading, because there are exceptions — always on medical grounds, frequently on religious grounds, and sometimes on philosophical grounds. Moreover, the thrust of mandates is not to forcibly require vaccination but to predicate eligibility for a service or benefit on adherence to the recommended immunization schedule of vaccination. ”

Y. Tony Yang on Linking Immunization Status and Eligibility for Welfare and Benefits Payments

And in some countries that already have mandates, they aren’t even doing a very good job of making sure that kids even get vaccinated. Many people will be surprised to learn that 14 European countries already mandate one or more vaccines, typically DTP, polio, and MMR.

What’s New in Vaccine Laws

Internationally, the idea of vaccine mandates is a big issue as we continue to see outbreaks of measles in Europe and other areas of the world.

“Parents who vaccinate their children should have confidence that they can take their children to child care without the fear that their children will be at risk of contracting a serious or potentially life-threatening illness because of the conscientious objections of others. ”

Australian Prime Minister Tony Abbott on “No Jab No Pay”

Unlike the Disneyland outbreak in California, the outbreaks in Europe are on a much bigger scale.

And with more cases we see what everyone fears – more deaths.

That’s why we are finally seeing new vaccine laws, including some that mandate vaccines in some other countries, including:

  • Australia – the Australian government began a “No Jab No Pay” plan in 2016 that removed the conscientious objector exemption on children’s vaccination for access to taxpayer funded Child Care Benefits, the Child Care Rebate and the Family Tax Benefit Part A end of year supplement.
  • Estonia – A proposal was put before the Estonian Parliament, the Riigikogu, to make immunizations compulsory.
  • Germany – a new law, if approved (it has already passed the Bundestag or national parliament), will require parents to have a medical consultation before deciding to delay or skip vaccines or they can be fined up to $2,800. Even with the law, in Germany, “vaccinations remain voluntary. But some politicians have suggested that mandatory vaccination is on the way if concerted efforts to encourage vaccinations don’t work.”
  • Italy – the Italian Parliament has given final approval to the Decree-Law Containing Urgent Measures on the Compulsory Vaccination of Children, which makes vaccinations against 12 diseases mandatory for children as a condition of school registration, for both private and public schools.
  • France – is working to expand their list of mandated vaccines to now include protection against 11 diseases instead of just three (diphtheria, tetanus, and polio). All of these vaccines were previously recommended to attend school, but were only voluntary.
  • Romania – a draft Vaccination Law could bring fines to parents who don’t vaccinate their kids and would keep them out of schools. Doctors could be fined too! The draft law is headed to Parliament for debate.

Again, none of these laws mean that anyone is being forced to vaccinate their kids.

Even in the case of vaccine mandates, they are simply requirements to attend daycare or school.

We are also seeing some new vaccine laws in the United States, including changes for the start of the 2017-2018 school year:

  • Indiana – pharmacists can give more vaccines, any vaccine that the CDC recommends, either with a prescription or by protocol for kids over are at least 11 years old and adults
  • Iowa – now requires a meningococcal vaccine for students entering 7th (one dose) and 12th (one or two doses) grades
  • Nevada – now requires a meningococcal vaccine for students entering 7th grade (one dose) and college (a dose after age 16 years)
  • Pennsylvania – unvaccinated students now only have a 5 day grace period at the start of the school year to get vaccinated (it used to be 8 months) before getting expelled from school.

It’s easy to navigate the new laws.

Get educated and get your kids vaccinated. Vaccines are safe, vaccines work, and vaccines are necessary.

What To Know About Vaccine Mandate Laws

Vaccine mandate laws are expanding as we are seeing more outbreaks of vaccine preventable diseases.

More Information on Vaccine Mandate Laws:

Updated August 20, 2017

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Hepatitis A Outbreaks

The hepatitis A vaccine, introduced in 1996, worked to decrease the incidence of hepatitis A infections in the United States.
The hepatitis A vaccine, introduced in 1996, worked to decrease the incidence of hepatitis A infections in the United States. Source – CDC Division of Viral Hepatitis

Hepatitis A is a now vaccine-preventable disease thanks to the hepatitis A vaccine that was first licensed in 1995.

Despite being added to the childhood immunization schedule in 1996 (kids living in high risk areas at first and gradually expanded to all kids in 2006), we do continue to see outbreaks of hepatitis A.

Hepatitis A

Although they are all viruses that can cause hepatitis, hepatitis A doesn’t share too much in common with hepatitis B and C.

Unlike hepatitis B and C, hepatitis A:

  • often doesn’t cause any symptoms at all in very young children
  • is spread by fecal-oral transmission (not blood and body fluids), typically from one person to another or after eating or drinking contaminated food or water
  • is much less likely to cause complications, but still did cause over 100 deaths from fulminant hepatitis A each year

In older children and adults, they symptoms of hepatitis A can include jaundice, fever, malaise, anorexia, nausea, abdominal discomfort, and dark urine, all of which can linger for up to two to six months.

Hepatitis A Epidemics and Outbreaks

In the prevaccine era, before the mid-1990s, hepatitis A outbreaks were common and “hepatitis A occurred in large nationwide epidemics”

After it became a nationally reportable disease in 1966, we saw peaks of hepatitis A disease in the early 1970s and again in the early 1990s and an estimated 180,000 infections per year in the United States.

Not surprisingly, those large nationwide epidemics soon disappeared as hepatitis A vaccination rates rose.

“Vaccination of high risk groups and public health measures have significantly reduced the number of overall hepatitis A cases and fulminant HAV cases. Nonetheless, hepatitis A results in substantial morbidity, with associated costs caused by medical care and work loss.”

CDC on the Epidemiology and Prevention of Vaccine-Preventable Diseases

We do still see some hepatitis A outbreaks though, including:

  • a multistate outbreak in 2016 linked to frozen strawberries (143 cases and 56 hospitalizations)
  • an outbreak in Hawaii in 2016 linked to raw scallops (292 cases and 74 hospitalizations)
  • a multistate outbreak in 2013 linked to pomegranate seeds from Turkey (162 cases and 71 hospitalizations)

So you can get hepatitis A if you are not immune and you are caught up in one of these outbreaks. Still, hepatitis A cases are at historic lows, with about 1,390 cases being reported in 2015.

Even more commonly, you might get hepatitis A if you are not immune and travel to a part of the world where hepatitis A either has high or intermediate endemicity (many people are infected), including many parts of Africa, Mexico, Central and South America, Eastern Europe, and Asia.

Or you could just be exposed to someone who traveled to or from one of these areas, became infected, and is still contagious.

There have also been outbreaks among men having sex with men, among IV drug users, and the homeless. These outbreaks are often the most deadly, and include fatal outbreaks in Michigan, California, and Colorado.

Avoiding Hepatitis A

How can you avoid getting caught up in one of these hepatitis A outbreaks?

Get vaccinated.

Can’t you just wash your hands or avoid eating contaminated food? Since you can get hepatitis A by simply eating food that has been prepared by someone who has hepatitis A and is still contagious, washing your own hands won’t be enough. Even drinking bottled water when traveling might not protect you from contaminated water if you use ice cubes or wash fruits and vegetables in water that might be contaminated.

Remember, if your child did not get a routine 2-dose series of the hepatitis A vaccine when they were between 12 to 23 months old, they can still get one at any time to get immunity against hepatitis A infections.

“On February 25, 2009, the Advisory Committee on Immunization Practices (ACIP) recommended routine hepatitis A vaccination for household members and other close personal contacts (e.g., regular babysitters) of adopted children newly arriving from countries with high or intermediate hepatitis A endemicity.”

ACIP on the  Latest Hepatitis A Vaccine Recommendations

Adults can get the vaccine too. It is an especially good idea if you are not immune and will be traveling out of the United States or are in another risk group, including food handlers, daycare workers, health care workers, and people who consume high risk foods, especially raw shellfish.

What to Know About Hepatitis A Outbreaks

Although we are at historic lows for cases of hepatitis A, make sure that your family has been vaccinated against hepatitis A so that they don’t get caught up in the next outbreak.

More Information on Hepatitis A Outbreaks:

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cVDPV

Circulating vaccine-derived polio virus or cVDPV are outbreaks of polio that are actually caused by the polio vaccine.

Very rarely, the attenuated (weakened) virus in the oral polio vaccine can revert to a form that can cause the person who was vaccinated or their close contact to actually develop polio.

It should not be confused with VAPP or vaccine-associated paralytic polio. With VAPP, the original strain of attenuated vaccine virus reverts to a form that can cause polio, but it does spread from one person to another, so does not lead to outbreaks.

cVDPV Outbreaks

Fortunately, both VAPP and cVDPV are rare.

How rare? VAPP only occurs in about 1 in every 1.27 million children receiving their first dose of OPV.

And according to the WHO, there had only been about 24 outbreaks of cVDPV over the past 10 years. Tragically, this has resulted in at least 750 cases of paralytic polio in 21 countries.

An outbreak of cVDPV in Syria will be controlled by 355 vaccination teams that will vaccinate up to 328,000 children.
The WHO reports that an outbreak of cVDPV in Syria will be controlled by 355 vaccination teams that will vaccinate up to 328,000 children.

A new outbreak of cVDPV in Syria adds to those numbers though.

After being polio free for 15 years, since 1999, Syria began having cases of wild type polio again in 2013 (35 cases) and 2014 (1 case). Those polio cases and the emergence of an outbreak of cVDPV2 (there are three strains of polio virus – this outbreak was caused by the type-2 strain) highlight the effects of years of poor immunization rates because of war.

While there are many challenges to getting kids vaccinated in Syria, up to 355 vaccination teams with 61 supervisors will be working out of five vaccine distribution centers to vaccinate 328,000 children to control the outbreak and get kids vaccinated.

Circulating Vaccine-Derived Polio Virus

Just like wild type polio, we can stop cVDPV by increasing vaccination rates and increasing access to improved sanitation facilities.

Why?

Although anti-vaccine folks routinely cry wolf about shedding, the oral polio vaccine really does shed – in the stool of people who have been recently vaccinated. You can then be exposed to the attenuated polio vaccine virus (which can help give immunity to others in the community by passive immunization) or a strain of cVDPV (which can, unfortunately, help give others, especially if they are not vaccinated, paralytic polio) if they are exposed to open sewage or can not practice proper hygiene, etc.

Can’t we just stop using the live, oral polio vaccine?

Although a serious side effect of the vaccine, the vaccine’s benefits clearly outweigh the risk of both VAPP and cVDPV while polio is endemic (lots of cases) in a region, after all, without the vaccine, hundreds of thousands of children would get polio and would be paralyzed.

In polio-free countries, the risks of VAPP and cVDPV becomes greater than the risk of polio though, and they move to the inactivated polio vaccine. That helps prevent a situation in which the polio vaccines actually causes more cases of polio than wild type polio viruses.

Eventually, all countries will move to the IPV vaccine as we move closer to polio eradication. We came one step closer to that point in April 2016 when all countries that were still using the oral polio vaccine switched from trivalent OPV (three strains) to bivalent OPV (two strains) for their routine immunization programs. This could eliminate up to 90% of cases of cVDPV (most are caused by the type-2 strain which is not in bOPV)!

What To Know About cVDPV

Circulating vaccine-derived polio virus outbreaks are a rare side effect of the oral polio vaccine.

More Information About cVDPV

Challenging the Concept of Herd Immunity

Before we talked about clusters of unvaccinated children, experts warned about pockets of susceptibles.
Before we talked about clusters of unvaccinated children, experts warned about pockets of susceptibles.
The idea of herd immunity has been around since at least 1923 and became used to describe “the indirect protection afforded to individuals by the presence and  proximity of others who are immune.”

That’s not much different from how the CDC defines herd immunity today:

A situation in which a sufficient proportion of a population is immune to an infectious disease (through vaccination and/or prior illness) to make its spread from person to person unlikely. Even individuals not vaccinated (such as newborns and those with chronic illnesses) are offered some protection because the disease has little opportunity to spread within the community.

Also called community immunity, it is often misunderstood by folks in the anti-vaccine movement.

Challenging the Concept of Herd Immunity

That the idea of herd immunity is being challenged is not new.

“Along with the growth of interest in herd immunity,  there has been a  proliferation of views of what it means or even of whether it exists at all.”

Paul E. M. Fine Herd Immunity: History, Theory, Practice

If you get educated about vaccines and understand how herd immunity works, it is easy to refute these challenges, especially the idea that herd immunity isn’t real just because we still have outbreaks of vaccine-preventable diseases among highly vaccinated communities.

Why do we still have outbreaks then?

It is mostly because we live in open communities that don’t mix randomly.

Keep in mind that the best model for herd immunity is a randomly mixing closed community – “one in which the probability of contact within any time interval is the same for every choice of two individuals in the population.”

Again, that doesn’t mean herd immunity doesn’t work.

It just means we can expect to see some outbreaks when someone in a well vaccinated community visits another community with lower vaccination levels and more disease, gets sick, and returns.

“However,  within the population of a community,  there may be pockets of  susceptibles, either because prior epidemics have failed to spread into the group or because they have not accepted immunization.”

John P. Fox Herd Immunity

You must also consider the size of the community when thinking about herd immunity, for example, a family, school, neighborhood, or city, versus the entire state. So you can have herd immunity levels of protection at the state or city level because of high average vaccination levels, but pockets of susceptibles who live in the same neighborhood or go to the same school can mean that you don’t have herd immunity in those places, leading to outbreaks.

“Hib vaccine coverage of less than 70% in the Gambia was sufficient to eliminate Hib disease, with similar findings seen in Navajo populations.”

RA Adegbola Elimination of Hib disease from The Gambia after…

Lastly, there is not one herd immunity level for all diseases. It is a separate threshold for each and every disease, depending on how easily it spreads, how many people are already immune, how long immunity lasts, if there is a vaccine, and the effectiveness of the vaccine, etc. That means that a community can have herd immunity for Hib and polio, but not the flu, and for rubella and measles, but not pertussis.

What happened in The Gambia is a great example of herd immunity. After introducing a three dose primary Hib immunization schedule (no booster dose), rates of Hib meningitis quickly went from 200 per 100,000 to none. A few years later, there were 6 cases of Hib meningitis in mostly vaccinated children (no booster dose) and in the majority of cases, “close contacts had a history of frequent or recent travel to Senegal, a neighboring country with strong kinship links with The Gambia and where vaccination against Hib was not introduced” until the following year.

With a Hib meningitis rate of 3 per 100,000, they are still far below pre-vaccine levels of disease, and their situation doesn’t mean that herd immunity isn’t real, as you will understand once you review these myths about herd immunity.

Myths About Herd Immunity

What are some common myths about herd immunity?

  • that natural immunity is better than getting vaccinated. Not True. Natural immunity often comes with a price. Remember, many vaccine-preventable diseases are life-threatening, even in this age of modern medicine.
  • you can just hide in the herd. Not True. “Freeloaders” can gamble and hope that their intentionally unvaccinated kids won’t get a vaccine-preventable disease, but it won’t always work. There is a risk to “free-riding, in which individuals profit from the protection provided by a well-vaccinated society without contributing to herd immunity themselves.”
  • most adults aren’t immune because they haven’t been vaccinated or don’t get boosters, but since we aren’t seeing that many outbreaks, herd immunity itself must be a myth. Not True. Adults were either born in the pre-vaccine era and likely have natural immunity or were born in the vaccine era and are vaccinated and immune. But again, herd immunity is disease specific, so when we talk about herd immunity for measles, it doesn’t matter if they have immunity against hepatitis A or Hib. And adults get few boosters or catch-up vaccines. Also, some vaccines, like Hib and Prevnar, have indirect effects, protecting adults even though they aren’t vaccinated because vaccinated kids are less likely to become infectious.
  • most vaccines wear off too soon to provide long lasting protection for herd immunity to be real. Not True. While waning immunity is a problem for a few diseases, like pertussis and mumps, and you need boosters for others, like tetanus, vaccine induced immunity is typically long lasting and often life-long.
  • herd immunity wasn’t developed by observing immunized people, it was all about natural immunity. Not True. The first experiments about herd immunity by Topley and Wilson in 1923 involved vaccinated mice. Ok, they weren’t immunized people, but it wasn’t just about natural immunity! And much earlier, in 1840, it was noted that “smallpox would be disturbed, and sometimes arrested, by vaccination, which protected a part of the population.” That’s herd immunity he was talking about.
  • herd immunity is not a scientifically validated concept. Not True. It has been well studied for almost 100 years.
  • if herd immunity was real, diseases would be eradicated once you reached herd immunity levels. Not True. Reaching herd immunity levels simply starts a downward trend in disease incidence. A little more work has to be done at the final stages of eradication, like was done for smallpox and is being done for polio.
  • natural immunity causes much of the decrease in mortality from a disease in the developed world, even before a vaccine is introduced. Not True. While it is certainly true that there was a big drop in mortality in the first half of the 20th century for most conditions because of improvements in sanitation, nutrition, and medical science, it was not a consequence of natural herd immunity. And we continue to see significant levels of mortality and morbidity for many diseases in the modern era, especially for those that can’t yet be prevented by a vaccine, like RSV, West Nile Virus, and malaria, etc.
  • vaccines aren’t 100% effective, so herd immunity can’t really work. Not True. Part of the equation to figure out the herd immunity threshold for a disease takes into account the effectiveness of a particular vaccine.
  • folks with medical exemptions for vaccines put the herd at risk just the same as those who intentionally skip vaccines. Not True. Children and adults with medical exemptions, including immune system problems, those getting treatments for cancer, and other true medical exemptions don’t have a choice about getting vaccinated.

So, like other anti-vaccine myths, none of the herd immunity myths you may have heard are true.

That makes it hard to understand why Dr. Russel Blaylock goes so far as to say “that vaccine-induced herd immunity is mostly myth can be proven quite simply.” Does he just not understand herd immunity? That is certainly a possibility, because “although herd immunity is crucial for the elimination of infectious diseases, its complexity and explicit relationship to health politics cause it to remain under-explained and under-used in vaccine advocacy. ”

He is also really big into pushing the idea that adults have no or little immunity, because when he was in medical school, he was “taught that all of the childhood vaccines lasted a lifetime,” but it has now been discovered that “most of these vaccines lost their effectiveness 2 to 10 years after being given.”

The thing is, Blaylock graduated medical school in 1971, when the only vaccines that were routinely used were smallpox (routine use ended in 1972), DPT, OPV, and MMR (it had just become available as a combined vaccine in 1971). Of these, it was long known that smallpox, diphtheria, and tetanus didn’t “last a lifetime,” and the live vaccines OPV and MMR, except for the mumps component, actually do.

Blaylock, like most anti-vaccine folks who push myths about herd immunity, is plain wrong. And like most anti-vaccine myths, using herd immunity denialism to convince parents that it is okay to skip or delay vaccines puts us all at risk for disease.

What To Know About Herd Immunity Myths

Herd immunity is not junk science or a false theory. Herd immunity is real, it works, and explains how people in a community are protected from a disease when vaccination rates are above a certain threshold.

More About Herd Immunity Myths

Who Is at Risk If You Don’t Vaccinate Your Kids?

Passive immunity doesn't last until 12 months, when infants get their first dose of the MMR vaccine, so they are at risk for disease.
Passive immunity doesn’t last until 12 months, when infants get their first dose of the MMR vaccine, so they are at risk for disease. Photo by Jamie Beverly (CC BY-SA 2.0)

Whenever there is a discussion about folks who intentionally choose to not vaccinate themselves or their kids, one of their arguments invariably is ‘why are you so worried if you and your kids are vaccinated?”

Here is an example:

“My argument is simple. If you are vaccinated, you should not have to fear an outbreak of any preventable disease. That’s what the vaccine is supposed to prevent, right? Therefore, why should anyone butt into someone else’s business and tell them they should vaccinate? If one and one’s dependents are vaccinated, why should they have to worry about my personal decision to not vaccinate?”

I personally don’t believe in vaccines

As most people understand, the argument is far from simple.

Who Is at Risk If You Don’t Vaccinate Your Kids?

There are many people who are at risk from those who are unvaccinated, including those who:

  • are too young to be vaccinated or fully vaccinated – remember, with the latest immunization schedule, kids don’t typically get their first MMR until age 12 months and their second until they are 4 to 6 years old
  • can’t be fully vaccinated and have a true medical exemption – this includes children and adults with some immune system problems, vaccine allergies, or other contraindications to getting one or more vaccines
  • were vaccinated, but later developed an immune system problem and their immunity has worn off – might include children with cancer, AIDS, those receiving immunosuppressive therapy after a transplant, or a condition that requires immunosuppressive doses of steroids, etc.
  • were vaccinated, but their vaccine didn’t work or has begun to wear off (waning immunity) – vaccines work well, but no vaccine is 100% effective

These are the children and adults that can be, and should be, protected by herd immunity. At least they can be when most folks are vaccinated.

“We want to create a ‘protective cocoon’ of immunized persons surrounding patients with primary immunodeficiency diseases so that they have less chance of being exposed to a potentially serious infection like influenza.”

Medical Advisory Committee of the Immune Deficiency Foundation

So while some folks who are against vaccines try to scare others about shedding, those who take care of kids with immune system problems and their families go out of the way to get everyone around them vaccinated so their kids aren’t at risk of getting a vaccine-preventable disease!

“…the increased risk of disease in the pediatric population, in part because of increasing rates of vaccine refusal and in some circumstances more rapid loss of immunity, increases potential exposure of immunodeficient children.”

Medical Advisory Committee of the Immune Deficiency Foundation

Tragically, not everyone has gotten the message, and we continue to see and hear about kids who are too young to be vaccinated or who couldn’t be vaccinated get exposed to those who got sick because they simply chose to not get vaccinated.

What to Know About Risks from the Unvaccinated

Intentionally unvaccinated children and adults put others at risk for vaccine-preventable diseases.

More Information on Risks from the Unvaccinated