Tag: pockets of susceptibles

Fact Checking Brian Hooker’s Statement to WA Legislators

Anti-vaccine folks brought out a lot of their big guns to a Washington State House Health Committee meeting about personal belief exemptions.

Brian Hooker makes a lot of statements about measles that mirror anti-vaccine talking points.

What was the meeting about?

A bill was introduced in the Washington Legislature that would limit non-medical vaccine exemptions by removing a philosophical or personal objection for the MMR vaccine.

Fact Checking Brian Hooker’s Statement to WA Legislators

Showing up to oppose the bill were Robert F. Kennedy Jr., Toni Bark, and Brian Hooker, none of which helped their side.

Why not?

Let’s see what Hooker said?

“There is a problem with measles in Washington State, but it’s not low vaccination rates, it’s actually high vaccination rates with a vaccine product unable to provide lifetime immunity or vigorous passive maternal protection to infants during the first year of life.”

Brian Hooker

Of course!

Unvaccinated kids are getting measles because we are vaccinating too many people. Why haven’t we noticed this before?

“When the measles vaccine was first introduced, most people over the age of 15 who had wild measles had lifetime immunity. In developed nations, like other communicable infections, measles was no longer dangerous except in rare circumstances because of inadequate nutrition, poor sanitation, and / or lack of healthcare.”

Brian Hooker

It is scary that Hooker makes statements like this, considering that he is an Associate Professor of Biology at Simpson University in Redding, California, where he specializes in chemistry and biology coursework.

When measles was killing kids in the 1950s in the United States, we had good nutrition, sanitation, and access to healthcare.

What was missing?

A measles vaccine!

“Because having the measles was a routine part of childhood, teens, adults, parents, and grandparents were immune. And because of maternal passive immunity, infants were protected.”

Brian Hooker

Yes, measles was once considered a rite of passage, but only because it had to be endured, as there was no way to avoid it. And you had to get sick and survive having measles to earn your lifetime immunity.

Tragically, not everyone did.

“But in fact, if the mothers of the children had wild measles when they were children and they are nursing, the babies may be protected. If the mothers were vaccinated, even if they are nursing, they may not be. Additionally, maternal antibodies transported across the placenta can provide vital immunity against measles for infants.”

Brian Hooker

While it is true that passive immunity from a mother who had a natural infection likely lasts longer than one who had vaccine induced immunity, it isn’t that much longer. At 6 months, few infants still have antibodies against measles, whether their mothers were vaccinated or had naturally acquired immunity. And it has nothing to do with nursing.

“As the editor of the journal Vaccine Dr. Gregory Poland of The Mayo Clinic stated in 1994, “…as measles immunization rates rise to high levels in a population, measles becomes a disease of immunized persons.”

Brian Hooker

Quoting Gregory Poland didn’t go so well for Toni Bark when she tried it at a Minnesota Senate hearing.

“But he also said that sometimes people who oppose the vaccines will pick out one sentence in the scientific study and extrapolate it to mean things that it does not mean… He said that measles is the most contagious disease that we know, and yet we found that fear and ignorance is more so.”

Senator Carla Nelson on The Anti-vaxxers Might Wish that What was Lost had not been Found

It makes you wonder why these folks are still quoting Poland.

“It was reported in the news and provided to legislators that in Clark County, WA there is a 22% exemption rate, but this is based on the voluntary Immunization Information Survey (IIS) which does not accurately reflect the vaccination status of all children enrolled in Washington schools. When compared to the more accurate CDC statistics for the state of Washington for MMR coverage among 19 to 35 month olds, it is 95.3% +/- 2.6%. The IIS erroneously reports this number at 81.8% and cannot be relied upon.”

Brian Hooker

These folks realize that the outbreaks aren’t occurring in the entire state of Washington, right? They are in very specific schools and communities where we do find very high levels of non-medical vaccine exemptions. These are the clusters of intentionally unvaccinated children experts have been warning about, the pockets of susceptibles.

“As I have already remarked, vaccination does not guarantee immunization and infectious diseases routinely break out in highly vaccinated communities. An example of this is pertussis outbreaks, which occur due to problems with the acellular pertussis portion of the DTaP and Tdap vaccine, creating asymptomatic carriers.”

Brian Hooker

Vaccination does not guarantee immunization?

I guess that is a way to say that vaccines aren’t 100% effective, but that is hardly an effective argument against getting vaccinated. Being intentionally unvaccinated often guarantees that you will get sick in an outbreak. Remember, even in outbreaks of pertussis and mumps, when waning immunity can be a concern, that attack rate is much higher in those who are unvaccinated.

“Over the past ten years in the U.S., there has been one reported death from the measles, and it is unclear based on the medical history of the patient whether and how measles played a role in their death. During the same time period (based on Vaccine Adverse Event Reporting System (VAERS) reports), there have been 105 reported deaths associated with the MMR or MMRV vaccinations.”

Brian Hooker

There have actually been seven measles deaths in the United States in the past 10 years, although only one was verified by the CDC.

Still, if Hooker is going to push unverified vaccine deaths in VAERS, why wouldn’t he also look at the reports of deaths from measles in the CDC Wonder database? And the 9 additional SSPE deaths?

And to doubt that measles actually killed a woman who got caught up in the 2015 measles outbreaks in Washington? What’s wrong with the modern anti-vaccine movement?!?

“You must not only protect those who are susceptible to poor infection outcome, but protect those who are susceptible to poor vaccination outcome, and to consider the unintended consequences of a fully vaccinated population that does not have lifetime immunity.”

Brian Hooker

It is becoming ever more clear that we must protect ourselves from these folks who push anti-vaccine propaganda and scare parents away from vaccinating and protecting their kids.

What does Hooker intend to do to “protect those who are susceptible to poor infection outcome?” How does he propose that everyone get lifetime immunity if they don’t get vaccinated?

“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

Anti-vaccine folks have already done such a good job scaring parents that too many of them are abusing vaccine exemptions. That’s why we are having more outbreaks, especially with the global rise in measles, and why states are having to tighten their vaccine laws.

More on Fact Checking Brian Hooker’s Statement to WA Legislators

Dr. Bob Puts the Nail in the Coffin of the Herd Immunity Argument

Dr. Bob Sears, who actually wrote a book about vaccines, seems to think that he and his podcasting sidekick have put the nail in the coffin “of trying to use the herd immunity argument to justify coerced vaccinated.”

Dr. Bob seems to think that herd immunity doesn't apply to vaccines.

The meme he shared even includes the hashtag stating that herd immunity doesn’t apply to vaccines.

Dr. Bob Puts the Nail in the Coffin of the Herd Immunity Argument

While arguing against the idea of herd immunity and for coerced vaccination are common among anti-vaccine folks, neither is true.

Herd immunity is real and no-one is going to force anyone to vaccinate their kids. Vaccine mandates do not mean forced vaccination.

What about the idea that “all vaccines wane within about 2-15 years, leaving vaccinated children & adults unprotected?”

If that were true, then wouldn’t everyone who got sick in latest outbreaks be vaccinated? Why are most folks unvaccinated?

So we are either getting a lot of outbreaks because of waning immunity or your titers are getting boosted because you are getting exposed to so much natural disease. Got it?

While waning immunity is an issue for some vaccines, like mumps and pertussis, the primary and secondary failure rates are still not as bad as Dr. Bob suggests, which is why, in an outbreak, the attack rate of disease is always higher among those who are unvaccinated and unprotected.

The numbers don't always add up correctly when anti-vax folks try to do math.
The numbers don’t always add up correctly when anti-vax folks try to do math.

Is herd immunity the main argument that’s made when experts suggest we need stronger vaccine laws? I always thought the main argument is that folks should just vaccinate and protect their kids, but maintaining herd immunity so that your intentionally unvaccinated kids don’t put everyone else at risk is a good reason too.

Does everyone see the problem with Melissa Floyd’s math? This probably won’t be on the SAT, but you still want to get this right…

Like many others are doing right now, she used state level data. Since many of the folks who don’t vaccinate their kids cluster together in the same communities and schools, the “2% of those filing for exemptions” end up making up 10, 20, or even 30% of some school’s student population.

“This means if you are a primary non-responder, you are walking around every day with a false sense of security, clinically unvaccinated for that particular disease.”

Melissa Floyd

This is the whole point of herd immunity!

Because vaccines aren’t 100% effective, we can walk around all day without actually thinking about it much, hoping that we can rely on the fact that most other people are also vaccinated and protected. That keeps disease out of our community or herd.

The system typically breaks down though, not because vaccines aren’t effective enough, but because too many folks don’t get vaccinated.

“A 2011 article in “Vaccines”, edited by Stanley Plotkin, says, “Much of the early theoretical work on herd immunity assumed that vaccines induced solid immunity against infection…” Theoretical… Assumed…”

Melissa Floyd

She should have read the whole article, or at least used the whole quote…

“Much of the early theoretical work on herd immunity assumed that vaccines induce solid immunity against infection and that populations mix at random, consistent with the simple herd immunity threshold for random vaccination of Vc = (1-1/R0), using the symbol Vc for the critical minimum proportion to be vaccinated (assuming 100% vaccine effectiveness). More recent research has addressed the complexities of imperfect immunity, heterogeneous populations, nonrandom vaccination, and freeloaders.”

Herd Immunity: A Rough Guide

It doesn’t say what she thinks it says…

“Indeed, one might argue that herd immunity, in the final analysis, is about protecting society itself.”

Herd Immunity: A Rough Guide

So why haven’t we eradicated measles like we said we would?

“What’s funny is after the measles vaccine was licensed in 1963, the medical community declared a goal of eradicating measles by 1967. But 1967 came and went and it still wasn’t gone, 1977, 1987, 2000… the dates kept getting pushed, and the result was always the same. Meanwhile they continued to increase the hypothesized “herd immunity threshold”, eventually winding up at the extremely high 95% you hear today. “

Melissa Floyd

That’s actually a good question.

What happened to the previous goals of eliminating measles?

“In 1966, the USA began an effort to eradicate the disease within its own borders. After a series of successes and setbacks, in 2000, 34 years after the initial goal was announced, measles was declared no longer to be endemic in the USA.”

Orenstein et al on Eradicating measles: a feasible goal?

Along the way, we have gone from an estimated 100 million cases and 5.8 million deaths in 1980 and an estimated 44 million cases and 1.1 deaths in 1995 to “just” 7 million cases and 89,780 deaths in 2016.

“Under the Global Vaccine Action Plan, measles and rubella are targeted for elimination in five WHO Regions by 2020.”

Measles

While there is doubt that we can truly eradicate measles with the current vaccine, we can certainly control and eliminate measles if folks stop listening to anti-vaccine propaganda and they get vaccinated and protected.

More on Dr. Bob and His Herd Immunity Arguments

Why Are We Having Measles Outbreaks If MMR Vaccination Rates Are Not Declining?

Some folks just can’t understand why we are having so many measles outbreaks these days.

It is actually really easy to figure out and find the decline in vaccination rates if you really look for it…

Why Are We Having Measles Outbreaks If MMR Vaccination Rates Are Not Declining?

And it is easy to understand why we are having these measles outbreaks, even though overall vaccination rates in a state might be good.

The problem is the clusters of unvaccinated people in very specific areas of each city, county, and state.

MMR vaccination rates have dropped over the years in Washington (red line) and Clark County (yellow line). Can we thank Andrew Wakefield, Jenny McCarthy, and Bob Sears, etc.?

These pockets of susceptibles put everyone at risk, especially those who are too young to be vaccinated, too young to be fully vaccinated, and those with true medical exemptions who can’t be vaccinated.

Looking at the state and county level rates of MMR vaccination by kindergarten, you can see that a lot more kids haven’t been getting vaccinated since 1990. In fact, while 97.6% of kindergarteners during the 1998-99 school year had their MMR vaccination, it quickly fell to about 90%, where it remains today. In Clark County, where we are currently seeing a large outbreak of measles, the drop was even worse.

Not surprisingly, this mirrors the vaccine exemption rates in these areas.

“What’s so important about all this data is that it destroys the false narrative. Vaccination rates haven’t gone down lately. Period. Ask any epidemiologist you know to run these numbers.”

JB Handley on CDC, Check YOUR Data: MMR Vaccination Rates are NOT Declining

Speaking of false narratives, many states now publish school and county level immunization rates, so it is easy to see past anti-vaccine propaganda and see that vaccination rates truly have gone down lately in areas that are dealing with outbreaks.

Immunization rates are very low at the Portland Waldorf School.

The Oregon Health Authority actually publishes annual lists of child, adolescent, and school immunization rates.

“I wanted to make sure and corroborate that data with data from the Oregon Health Authority, which they conveniently don’t publish very often, but someone sent me their data from 2014, showing that 97.1% of 7th graders in Oregon have received an MMR vaccine! Where’s the decline?”

JB Handley on CDC, Check YOUR Data: MMR Vaccination Rates are NOT Declining

In 2017, 95.5% of teens in Oregon had received one dose of the MMR vaccine. Only 90% had received the recommended two doses. Rates in Multonah County, near the current outbreak in Washington, were actually a little better, at 96.7% (one dose) and 92% (2 doses).

Still, there are plenty of schools with much lower rates, creating the pockets of susceptibles that are causing these outbreaks.

Where’s the decline?

Have you checked the Portland Waldorf school?

While schools with higher rates help to boost the average rates for the county and state, the schools and communities with low rates are prime for outbreaks.

SchoolMMR Rates
Orchards Elementary School71.4%
Minnehaha Elementary School89.3%
Cornerstone Christian Academy?
Hearthwood Elementary School72.2%
Home Connection86.7%
Homelink River61.1%
Slavic Christian Academy?
Image Elementary School78%
Eisenhower Elementary School89%
Tukes Valley Primary and Middle School​?
Maple Grove School?
Evergreen High School?

In Washington, for example, the schools involved in the outbreak (at least the ones that report) all have immunization rates below the state and county levels.

If you are on the fence about vaccinating your kids, check where you’re getting your information from if what you are hearing is scaring you.

Vaccines are safe, with few risks, and necessary. Get vaccinated and stop the outbreaks.

Why Are We Having Measles Outbreaks If MMR Vaccination Rates Are Not Declining?

Did Gregory Poland Really Say That MMR Vaccines Can’t Prevent Measles Outbreaks?

One of the pillars of the anti-vaccine movement is their belief that vaccines don’t even work.

They even think that they have graphs to prove it! They don’t…

Did Gregory Poland Really Say That MMR Vaccines Can’t Prevent Measles Outbreaks?

To help them try and argue their point, they also seem to like to cherry pick and misuse quotes from real experts.

Anti-vaccine propaganda from Lawrence Solomon.
Is that what Dr. Poland said?

In 2012, Gregory Poland, the Editor-in-Chief of the journal Vaccine, did publish the article, The Re-Emergence of Measles in Developed Countries: Time to Develop the Next-Generation Measles Vaccines?

No where in the article does he say that the measles vaccine can’t prevent measles outbreaks.

He is just saying that since the vaccine isn’t 100% effective and because measles is so contagious, that it can’t prevent all measles outbreaks.

“Thus, measles outbreaks also occur even among highly vaccinated populations because of primary and secondary vaccine failure, which results in gradually larger pools of susceptible persons and outbreaks once measles is introduced.”

Poland et al on The Re-Emergence of Measles in Developed Countries: Time to Develop the Next-Generation Measles Vaccines?

And we likely won’t be able to eradicate measles with our current measles vaccine, “even though measles can be controlled, and even eliminated in some regions for defined periods of time.”

“Thus, while an excellent vaccine, a dilemma remains.”

Poland et al on The Re-Emergence of Measles in Developed Countries: Time to Develop the Next-Generation Measles Vaccines?

The dilemma is that measles is still around and that people who are too young to be vaccinated, too young to be fully vaccinated, and those with immune system problems who can’t be vaccinated sometimes get measles, in addition to folks who are intentionally unvaccinated.

With a better vaccine, fewer people would get caught up in outbreaks that are typically triggered by folks who are intentionally unvaccinated.

Remember, most outbreaks are traced back to someone who is unvaccinated. This is the person Dr. Poland is describing when he says “once measles is introduced,” as the endemic spread of measles has been eliminated in the United States. All cases are reintroduced from outside the country, typically when someone who is intentionally not vaccinated travels overseas and then returns with measles while they are still contagious.

“But he also said that sometimes people who oppose the vaccines will pick out one sentence in the scientific study and extrapolate it to mean things that it does not mean… He said that measles is the most contagious disease that we know, and yet we found that fear and ignorance is more so.”

Senator Carla Nelson on The Anti-vaxxers Might Wish that What was Lost had not been Found

Unfortunately, a better measles vaccine still won’t protect us from anti-vaccine propaganda.

Vaccines are safe, with few risks, and necessary. Get vaccinated and stop the outbreaks. You don’t have to wait for a new measles vaccine…

More on Did Gregory Poland Say That MMR Vaccines Can’t Prevent Measles Outbreaks?

Why Are We Worried About 60,000 Unvaccinated Kids?

In the recent New York Times OpEd, How to Inoculate Against Anti-Vaxxers, the editorial board mentioned the 60,000 children in Texas who “remain wholly unvaccinated thanks in part to an aggressive anti-vaccine lobby.”

“But there’s like 74 million children, so I think that’s a pretty small number. I don’t know why you guys are freaking out about 60,000 really healthy babies running around. Do you know?

Hillary Simpson

Hillary Simpson obviously doesn’t understand how herd immunity works.

Do you?

Why Are We Worried About 60,000 Unvaccinated Kids?

First things first, though.

Just how many unvaccinated kids are there in Texas? How about the United States?

It is actually hard to know exactly.

It's easy to forget, with so much talk about anti-vaxxers these days, but the great majority of parents vaccinate and protect their kids!
It’s easy to forget, with so much talk about anti-vaxxers these days, but the great majority of parents vaccinate and protect their kids!

In Texas, for instance, while only a small percentage of kids get non-medical vaccine exemptions, with about 7 million children in the state (yes, there are 74 million children in the United States, but that’s not how you measure herd immunity), that adds up to a lot of unvaccinated kids.

In addition to about 60,000 unvaccinated kids in school, there are homeschooled children who aren’t vaccinated.

“We’re probably looking at more than 100,000 kids in the state of Texas who are not getting their vaccines.”

Dr. Peter J. Hotez: “A Scary Anti-Science Movement Has Become Very Strong in Texas”

But still, should we be worried about 100,000 unvaccinated kids, when there are 7 million kids in Texas?

Don’t those immunization levels still keep us above herd immunity levels of protection?

Well, they likely would, and this would indeed be less concerning if the unvaccinated children were spread out randomly throughout the entire state. Of course, that’s not what happens and we instead get clusters of unvaccinated children (and adults) in very specific schools, neighborhoods, and even churches.

There are higher numbers of unvaccinated kids in very specific parts of the states, leading to pockets where it is more likely that an outbreak could happen.
There are higher numbers of unvaccinated kids in very specific parts of the states, leading to pockets where it is more likely that an outbreak could happen.

So while it can seem like we have herd immunity levels of protection at the state or city level because of high average vaccination levels, these pockets of susceptibles who are unvaccinated and live in the same neighborhood or go to the same school (where is the Waldorf school in Texas?) can mean that we don’t have herd immunity in those places, leading to outbreaks.

And that’s why we get concerned about 60 to 100,000 unvaccinated children who:

Still, remember that the great majority of parents understand the benefits of vaccines, are not scared by anti-vaccine propaganda, and vaccinate their kids.

In 2015, for example, only 1.3% of children in the United States had received no vaccines by age 24 months. And more than 90% of children completed their primary series of vaccines.

That doesn’t mean that we shouldn’t be concerned about those who don’t, but maybe you should be a little bit more concerned about your decision to not vaccinate your kids.

More on Clusters of Unvaccinated Kids

The First Measles Case of 2018 is at IU Bloomington

And the first measles case of 2018 is in…

  • Bloomington, Indiana

Unvaccinated children exposed to measles are quarantined for at least 21 days.

A student at Indiana University in Bloomington was diagnosed with measles on January 6.

The student may have exposed others between the time they arrived on campus on January 2, moved into her dorm (McNutt Residence Hall), and got diagnosed on January 6.

Fortunately, classes haven’t started yet, so exposure to others might have been lower than they typically might have been.

She likely did expose others on January 2:

  • on a flight from Mumbai, India to Newark Liberty International Airport
  • during a layover in Newark Liberty International Airport
  • on a flight from Newark to Indianapolis International Airport
  • at Indianapolis International Airport

Because measles has a long incubation period, remember that it might not be until January 23 that you develop symptoms if you were exposed are not immune (two doses of vaccine or natural immunity).

Indiana Measles Outbreaks

Surprisingly, this is not the first case of measles at this campus in recent years. Just four years ago, another student at Indiana University Bloomington was diagnosed with measles.

Or maybe it shouldn’t be so surprising.

Indiana has had some large measles outbreaks triggered by unvaccinated travelers returning to the state.
Indiana has had some large measles outbreaks triggered by unvaccinated travelers returning to the state.

There has been a lot of measles in Indiana in recent years:

  • an outbreak caused by an unvaccinated traveler who got 13 other people sick in 2011
  • another outbreak in 2012, also triggered by an unvaccinated traveler, also got 13 other people sick

In fact, since 2010, there have been at least 34 cases of measles in Indiana, including the latest case at IU Bloomington. Almost all have been unvaccinated.

And that’s with a pretty good vaccination rate.

Why?

Pockets of susceptibles, or so-called clusters of unvaccinated people, who get measles and then put the rest of us at risk.

Get educated.

Stop the outbreaks.

Vaccines work. Vaccines are safe and vaccines are necessary.

What to Know About Measles in Indiana

Indiana has been one of the states where we have seen measles outbreaks linked to clusters of unvaccinated people and is home to the first measles case of 2018.

More on Measles in Indiana

Updated January 13, 2018

Pertussis Outbreaks

Like measles and mumps, pertussis, or whooping cough, is another vaccine-preventable disease that has been increasing in recent years.

Pre-Vaccine Era Pertussis Outbreaks

Pertussis has been known since at least the Middle Ages, although the bacteria that causes pertussis, Bordetella pertussis, wasn’t discovered until 1906.

Like measles, pertussis was a top killer of young children in the pre-vaccine era.
Like measles, pertussis was a top killer of young children in the pre-vaccine era.

That discovery led to the later development of the first pertussis vaccines, but before then, pertussis was a big killer, with epidemic cycles every 2 to 5 years.

During one of these cycles in the United States, from 1926 to 1930, there were:

  • 909,705 cases, and
  • 36,013 deaths

Unfortunately, even natural infection doesn’t provide life-long immunity, so adults would get pertussis and give it to susceptible kids, who were most likely to die during these epidemics.

But even in non-epidemic years, a lot of folks got pertussis. The number of reported cases ranged from “just” 161,799 in 1928 to 202,210 in 1926. And during one of the biggest years, 1934, there were 265,269 cases!

Post-Vaccine Era Pertussis Outbreaks

That changed in the vaccine era.

The first pertussis vaccines were developed in the 1930s and became more widely used in the 1940s when it was combined into the whole-cell DTP vaccine.

This was replaced with the acellular DTaP vaccine in 1997, with the Tdap vaccine being added to the vaccine schedule in 2006.

These vaccines helped to greatly reduce how many people got pertussis and how many people died from pertussis:

  • 1940 – 183,866 cases
  • 1950 – 120,718 cases and 1, 118 deaths
  • 1960 – 14,809 cases and 118 deaths
  • 1970 – 4,249 cases and 12 deaths
  • 1980 – 1,730 cases and 11 deaths
  • 1990 – 4,570 cases and 12 deaths
  • 2000 – 7,867 cases and 12 deaths
  • 2010 – 27,550 cases and 26 deaths

They never eradicated pertussis though, and as you can see, recently, pertussis cases have started to rise again.

Is it a coincidence that whooping cough came back as more folks began to skip and delay vaccines for their kids?
Is it a coincidence that whooping cough came back as more folks began to skip and delay vaccines for their kids?

In 2012, there were 48,277 cases of pertussis in the United States, the most since 1950, when we had 68,687 cases. Unfortunately, with the rise in cases, we are also seeing the tragic consequences of this disease – 20 deaths in 2012, mostly infants under age 3 months.

Pertussis cases remained steady, but high, in 2013 and 2014, at around 30,000 cases in the United States.

In California, pertussis reached epidemic levels. The California Department of Public Health reported at least 11,114 cases in 2014 – the highest numbers of pertussis cases in the state in 70 years!

And as expected with the rise in cases, there were 3 pertussis related deaths in California that year – all infants who had contracted pertussis when they were less than 8 weeks old. Two of the infants became sick in 2013, but the third, a 5-week-old baby, got infected in 2014.

Another baby, only 25 days old died in early 2015, but will be counted as the 2nd death of 2014 since that is when the illness started. About 383 patients, mostly infants who are less than 4 months old, were hospitalized in California that year, including 80 who required intensive care. And according to the California Department of Public Health, about 82% of the cases in infants were born to mothers who did not receive a dose of Tdap during their third trimester of pregnancy.

What’s happened since then?

Pertussis cases began to fall! In fact, with just under 18,000 cases in the United States, 2016 may have ended with the lowest number of pertussis cases since 2008.

Still, with just 1,830 pertussis cases in California in 2016, there were two deaths – both infants who were younger than 3 months of age when they got sick. And there was at least one death in 2017, with similar rates of disease, although reports are still preliminary. There was also a bump up in the pertussis case counts in 2017, to just under 19,000 cases.

The preliminary numbers for 2018 look better though – about 13,439 cases nationwide.

Why So Many Pertussis Outbreaks?

Ever since a 2010 California pertussis outbreak, in which there were 9,154 cases of pertussis, the most in 63 years, and 10 infants died, many people, especially parents, began wondering why we were seeing more pertussis these days.

Is it because the pertussis vaccines simply don’t work, as the anti-vaccine movement would have you think?

Or is it because there are higher rates of unvaccinated kids these days and parents using alternative immunization schedules, instead of the standard immunization schedule from the CDC?

James Cherry, MD is an expert on pertussis and pertussis vaccines.
James Cherry, MD is an expert on pertussis and pertussis vaccines.

A commentary, Why Do Pertussis Vaccines Fail?, by James Cherry, MD, gave us some answers.

While the title of the article might have you think that all of the blame lies with the pertussis vaccines, that certainly isn’t the case. While there can be vaccine failures with the pertussis vaccines, just like any other vaccine, that doesn’t mean that the vaccine doesn’t work for most children.

One of the problems is that the DTaP vaccine likely isn’t as effective as the older DTP vaccine. So instead of efficacy of 84 to 85%, as was once believed, it is likely closer to just 71 to 78%.

Other issues, including waning immunity, the possibility of an incorrect balance of antigens in the vaccine that could create a blocking effect, and genetic changes in the B. pertussis bacteria, could also possibly lead to increased vaccine failure rates.

So it isn’t that the pertussis vaccines don’t work.

That should be easy to see when you look at the pertussis rates in California, when the highest rates by far were in infants less than 6 months of age (434 per 100,000 people). In contrast, children who were 6 months to 6 years old had a rate of only 62 per 100,000.

And the results of a study that were presented at the 49th annual meeting of the Infectious Diseases Society of America in Boston show just how important the pertussis vaccine is, as:

  • vaccine effectiveness was 98.1 percent among children who received their 5th dose within the past year
  • long term effectiveness – children who were five or more years past their last DTaP dose – was about 71 percent
  • children who had never received any doses of DTaP (unvaccinated children) faced odds of having whooping cough at least eight times higher than children who received all five doses

It is also important to note that the high rates seen in 2010 in California are still well below the rates that were seen in the pre-vaccination era, when the attack rate of pertussis in the United States was as high as 157 per 100,000 people, with about 200,000 cases a year.

What’s the answer?

“The present “resurgence of pertussis” is mainly due to greater awareness and the use of PCR for diagnosis. There are also many other factors which have contributed to the “resurgence.” New vaccines are clearly needed; with our present vaccines (DTaP and adolescent and adult formulated tetanus and diphtheria toxoids and acellular pertussis vaccine (Tdap)), if used correctly, severe pertussis and deaths in infants can be prevented.”

James D. Cherry, MD on The History of Pertussis (Whooping Cough); 1906 – 2015: Facts, Myths, and Misconceptions

It certainly isn’t for more kids to follow non-standard, parent-selected, delayed protection vaccine schedules or to simply skip vaccines all together. Since natural immunity isn’t going to keep newborns and infants from getting pertussis, the ages which are most at risk for life-threatening infections, they can catch pertussis from people around them, including those working on their natural immunity. Natural infections don’t even provide life-long protection against pertussis, as some people believe. That natural immunity wanes fairly quickly too.

Not Vaccinated? No Kisses!
Not Vaccinated? No Kisses!

The future of pertussis control is more likely going to be in maximizing our current vaccination program, including getting more teens and adults to get the Tdap vaccine, especially when women are pregnant.

That’s the best strategy, at least until new pertussis vaccines are developed. It provides a lot of benefits. According to the CDC, like with the flu vaccine, when you get a pertussis vaccine, in addition to protecting yourself and those people around you, “people who do catch whooping cough after being vaccinated are much less likely to be hospitalized or die from the disease.”

Unfortunately, not everyone has gotten the message. And because of waning immunity, children who aren’t vaccinated against pertussis can’t “hide in the herd” and rely on the rest of us who do vaccinate our children to provide them with protection. Instead, since they are at a higher risk, they get pertussis and get even more people sick.

This slogan, during a whooping cough epidemic, reminded parents to get their kids vaccinated now.
This slogan, during a whooping cough epidemic, reminded parents to get their kids vaccinated now.

In one study, Parental refusal of pertussis vaccination is associated with an increased risk of pertussis infection in children, researchers found that “vaccine refusers had a 23-fold increased risk for pertussis when compared with vaccine acceptors, and 11% of pertussis cases in the entire study population were attributed to vaccine refusal.” The highly contagious nature of pertussis then means every primary case is probably going to infect as many as 17 other people. That’s why it makes sense that higher rates of children using vaccine exemptions could be at least one of the factors in these outbreaks.

In fact, several studies, including, Geographic Clustering of Nonmedical Exemptions to School Immunization Requirements and Associations With Geographic Clustering of Pertussis, found that “geographic pockets of vaccine refusal are associated with the risk of pertussis outbreaks in the whole community.”

Get educated. Vaccines are safe and as you can see with the rise in outbreaks, vaccines are necessary.

What to Know About Pertussis Outbreaks

Many factors are responsible for the rise in pertussis outbreaks in recent years, but it is clear that being unvaccinated and unprotected put you at greatest risk for getting pertussis and passing it on to others.

More on Pertussis Outbreaks