Tag: pertussis

Making a Better Pertussis Vaccine

So we know that we need a better pertussis vaccine.

DTaP and Tdap just aren’t doing the job that they should be doing.

Whooping Cough is back, again.
Whooping Cough is back, again.

So when will we get one?

Making a Better Pertussis Vaccine

Since anti-vaccine folks are always talking about the 300 new vaccines in the pipeline, you would think that we would have had several new pertussis vaccines by now…

Unfortunately, we don’t.

What we do have is some good candidates, including:

  • new acellular pertussis vaccines, either with more antigens or an adjuvant
  • a new live attenuated nasal vaccine, BPZE1
  • new whole-cell vaccines with reduced endotoxin contents (so should have fewer side effects that then original whole-cell pertussis vaccine – DTP)

Before you get too excited, keep in mind that none of these vaccines will be available in your pediatrician’s office any time soon. Developing a new vaccine takes a lot of time.

BPZE1 has started phase 2a trials though.

What do we do until we get new pertussis vaccines?

“We should be more vigilant than we have been in the past to recognize and treat pertussis in all age groups so that transmission to young infants is reduced. Most important (although not discussed in this review) is to ensure that all pregnant women receive the Tdap vaccine between 27 and 36 weeks’ gestation with each pregnancy. Also, we should consider routinely administering Tdap vaccine every 3 years to all adolescents and adults who were primed with a DTaP vaccine.”

James D. Cherry on The 112-Year Odyssey of Pertussis and Pertussis Vaccines—Mistakes Made and Implications for the Future

We should keep using the pertussis vaccines we have!

Vaccines work, even when they aren’t as effective as we would like.

More on Making a Better Pertussis Vaccine

About Those Lawsuits That Almost Put Vaccine Manufacturers out of Business

So you likely know that there were a bunch of lawsuits against manufacturers of the DPT vaccine in the early and mid 1980s.

“As the number of lawsuits grew to hundreds during the early 1980s, the pharmaceutical companies making vaccines saw their liability insurance bills soar. Worried not only about multimillion-dollar settlements, but also even the legal costs of defending themselves successfully, several companies simply stopped making vaccine.”

How a Media Scare On Vaccine Started a ‘near-Epidemic’

That’s why the National Vaccine Injury Compensation Act passed in 1986, creating the National Vaccine Injury Compensation Program and the Vaccine Court.

About Those Lawsuits That Almost Put Vaccine Manufacturers out of Business

But did those DPT vaccine lawsuits prove that vaccines aren’t safe?

Is that why vaccine manufacturers needed help to limit their liability?

“The total amount claimed in 1984 DTP vaccine suits ($1.3 billion) is more than 20 times the total value of 1984 sales of DTP vaccine at the market price of $2.80 per dose.”

Hinman on DTP Vaccine Litigation

Of course not!

While the older DPT vaccine did cause more local reactions, pain, and fever than the newer DTaP vaccine that replaced it, all of the serious reactions that triggered the lawsuits were later found to not be caused by the vaccine.

Most of the DPT lawsuits were thought to be frivolous.

That’s not surprising, as the same vaccine lawsuits that were succeeding in driving vaccine manufacturers out of business in the United States were failing in the UK and Canada!

This included the Loveday judgment in Great Britain’s High Court of Justice, Queen’s Bench Division and the Rothwell judgment in the Supreme Court of Ontario, Canada, both decided in 1988, with justices ruling that there was “insufficient evidence to demonstrate that pertussis vaccine can cause permanent brain damage in children.”

Similar cases were succeeding in the US though..

“The number (and dollar value) of suits increased in 1982, a year when broadcast and print media began to devote considerable attention to the alleged hazards associated with the use of pertussis-containing vaccines. Most of the media coverage has emphasized alleged risks of pertussis vaccines and has given relatively little attention to the benefits of their use.”

Hinman on DTP Vaccine Litigation

Most experts knew that most of the lawsuits were frivolous, but they weren’t able to stop the damage that was to come, as:

  • the DPT: Vaccine Roulette special aired on TV
  • Barbara Loe Fisher, believing that her child was damaged by the DPT vaccine, formed the Dissatisfied Parents Together organization and wrote the book DPT: A Shot in the Dark, which later influenced Bob Sears
  • there were temporary shortages of DTP vaccine in 1984, as “two of the three American manufacturers of the product decided to halt or restrict its sales.”

What else happened? I mean besides all of the studies proving the DPT vaccine was safe?

Parents who had been scared by the DPT controversy were ready and primed when Andy Wakefield showed up and told them that they had something new to worry about – the MMR vaccine and autism.

And of course, pertussis is now returning, as more parents are scared to vaccinate their kids and the newer DTaP vaccine isn’t as effective as DPT.

More on Those Lawsuits That Almost Put Vaccine Manufacturers out of Business

Are the Tdap and DTaP Vaccines the Same Thing?

You have probably already figured out the Tdap and DTaP aren’t the same vaccine, after all, if they were, why would they have different names, right?

Are the Tdap and DTaP Vaccines the Same Thing?

I bet you don’t know the difference between the two vaccines though.

Yes, they both are both combination vaccines that protect against diphtheria, tetanus, and pertussis.

The difference is that one (DTaP) is used as the primary series for infants and younger children (age 6 years and under) and the other (Tdap) is given to older children (age 7 years and above), teens, and adults.

Okay, that’s not the only difference.

The DTaP vaccine actually contains more diphtheria and pertussis antigens than Tdap, which is why it has the capital “D” and “P” in its name. The amount of tetanus toxoid antigens are about the same in both vaccines.

So Tdap contains the same amount of tetanus toxoid, plus a reduced amount of diphtheria and acellular pertussis antigens, as compared to DTaP.

While you would think that older children and adults would get the vaccine with the higher amount of antigens, since they are bigger, that’s not how this works. Vaccines typically start working at the injection site, so body size isn’t a key factor in determining the amount of ingredients.

As a booster dose of vaccine, the lower amount of antigens works just fine and helps reduce the risk of side effects from repeated doses that you might get with higher antigen counts.

More on Tdap vs DTaP

Alternative Names for Vaccine Preventable Diseases

You know all of the names – measles, mumps, rubella, diphtheria, whooping cough, etc.

But do you know why they used to call 10-day measles?

And which disease causes a 100-day cough?

Alternative Names for Vaccine Preventable Diseases

Back in the day, when these diseases were more common, they used much more descriptive terms and nicknames, in addition to their official names.

Why was measles known as 10-day measles?

Because there was also a 3-day measles!

MeaslesRubella
10-day measles3-day measles
red measlesGerman measles
rubeola

Unfortunately, 10-day measles made you feel miserable for 10 days!

Although a vaccine was available, it took a little more time to get measles under better control.

Can you guess which disease was known to cause a 100-day cough?

That’s right, it’s whooping cough or pertussis.

“I honestly felt like it was never going to go away. The doctor told me it was 100 day cough, so I was counting the days while Googling to see if there was anything that could help. I tried everything, you name it, I tried it, and nothing worked. It came to 120 days and I couldn’t understand why it wasn’t gone. I then researched and found that babies take longer to get over whooping cough.”

Fern’s Story – Whooping Cough

Fortunately, the cough doesn’t typically last that long if you are vaccinated and still get pertussis.

What do they call rabies?

Mad dog disease.

But that’s an easy one.

Which disease was known as “the Strangling Angel?”

“The breathing became much more difficult, with a kind of rattling stertor, as if the patient was actually strangling, the voice being exceeding hoarse and hollow, exactly resembling that from venereal ulcers in the fauces. This noise, in speaking and breathing, was so peculiar, that any person in the least conversant with the disease might easily know it by this odd noise; from whence, indeed, the Spanish physicians gave it the name of garrotillo, expressing the noise such make as are strangling with a rope.”

Edward Headlam Greenhow on Diphtheria

How about “The Crippler?”

Fight Polio Poster
Polio, also known as infantile paralysis, was known as “The Crippler.”

The “Speckled Monster?”

Even mild smallpox, as depicted on this WHO Smallpox Recognition Card, included flu like symptoms, a few weeks of pustules, and then waiting for the lesions to scab over...
Even mild smallpox, as depicted on this WHO Smallpox Recognition Card, included flu like symptoms, a few weeks of pustules, and then waiting for the lesions to scab over…

We forget these names, because we don’t see these diseases anymore.

“…for those trained in pediatrics in the 1970s, Hib (Haemophilus influenzae type b) was a horror.”

Walter Orenstein

Do you remember that measles was called a “harmless killer?”

Be sure to think about how these now vaccine-preventable diseases got their nicknames before you think about skipping or delaying your child’s vaccines.

More on Alternative Names for Vaccine Preventable Diseases

Vaccines – Year in Review 2018

Another year has passed and although anti-vaccine folks keep talking about those 300 vaccines in pipeline, there were few new developments in the vaccine world in 2018.

Bob Sears got in trouble with the Medical Board of California over vaccine exemptions.
This happened in 2018.

Well, maybe that’s not entirely true.

Vaccines – Year in Review 2018

So what can we say about 2018 when it comes to vaccines?

Well, we did get some new ones!

  • approved by the FDA in late 2017, a new hepatitis B vaccine for adults, Heplisav-B, the formal recommendation for its use from the ACIP came on February 21, 2018
  • although it was both approved by the FDA and formally recommended by the ACIP in late 2017, Shingrix, the new shingles vaccine, became more widely available in 2018 – well kind of – there have been a lot of shortages due to high demand for the vaccine
  • Vaxelis, a hexavalent vaccine that combines DTaP-IPV-Hib-HepB into one shot was FDA approved on December 21, 2018, but likely won’t be available for a few more years
  • FluMist, the nasal spray flu vaccine, returned

And we lost one… Last year was the first full year that Menomune, an older meningococcal vaccine, was no longer available. It was discontinued because of low demand, as we began to use the newer vaccines, Menactra and Menveo instead.

In other immunization news:

  • a 2017 shortage of yellow fever vaccine continued into 2018
  • a shortage of monovalent pediatric hepatitis B vaccine will continue into 2019 (doesn’t affect combination vaccines with hepatitis B)
  • Gardasil 9 received an expanded recommendation – women and men between the ages of 27 and 45 years can now get vaccinated and protected with this HPV vaccine
  • the hepatitis A vaccine got a lower age recommendation – at least in special situations – “HepA vaccine be administered to infants aged 6–11 months traveling outside the United States when protection against HAV is recommended.”
  • the recommendation to use a third dose of MMR to control outbreaks of mumps was formally approved
  • the WHO updated its recommendations for use of the dengue fever vaccine (Dengvaxia) to makes sure that only dengue-seropositive persons are vaccinated, as they found an increased risk of severe dengue in seronegative people who were vaccinated
  • Of the 163 million to 168 million doses of flu vaccine that will be distributed in the United States for the 2018-2019 season, more than 80% will be thimerosal free.
  • China had an issue with substandard DTaP vaccines made by one company in one part of the country
  • India had an issue with contaminated polio vaccines made by one company in one part of the country – bivalent oral polio vaccines (two strains) still contained all three strains of polio vaccine virus
  • Measles cases and deaths spiked globally because of gaps in vaccination coverage

If you didn’t hear about any of those things in the news, you may have heard about the death of two young children in Samoa after they received an MMR vaccine. That tragedy almost certainly was caused by an error in administering/mixing the vaccines, and not because there was anything wrong with the vaccines themselves.

Need help getting educated about vaccines? Despite continued outbreaks, 2018 was a good year for vaccine advocates and vaccine education.

Several good books about vaccines were published, including:

And in case you missed it, we found out that:

Of course, for most of us, none of this is really news. We know that vaccines are safe, effective, and necessary.

And sadly, Betty Bumpers died. We can honor her legacy by continuing her work and helping to make sure that every child gets vaccinated and protected.

More on Vaccines Year in Review 2018

Do More Vaccinated or Unvaccinated Kids Get Pertussis?

While this seems like a simple question, the answer is a bit more complicated than most people imagine.

Do More Vaccinated or Unvaccinated Kids Get Pertussis?

For anti-vaccine folks, the answer is clear – more vaccinated kids get pertussis. They put all of the blame for pertussis outbreaks on waning immunity. Of course, that’s not the whole story.

While 10% of kids got pertussis, unless you are at a Waldorf school, it is unusual to find that many completely unvaccinated children.
While 10% of kids got pertussis, unless you are at a Waldorf school, it is unusual to find that many completely unvaccinated children. Plus, we don’t know the vaccine history of 40% of these kids.

While it might technically be true that more vaccinated kids get pertussis in the average outbreak, that’s only because there are many more vaccinated kids!

A more accurate and useful answer, taking into account attack rates, makes it clear that a higher percentage of unvaccinated kids get pertussis in these outbreaks.

“In conclusion we have described a school-based outbreak of pertussis that may have been fueled by moderate vaccine effectiveness combined with a failure to vaccinate.”

Terrenella et al on Vaccine effectiveness of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine during a pertussis outbreak in Maine

In a pertussis outbreak in Maine, attack rates were much higher in unvaccinated kids, even though more vaccinated kids got pertussis. While 29 of 214 vaccinated kids got pertussis, a much higher percentage of unvaccinated kids got sick – 6 of 28.

That means your risk of getting pertussis was much higher if you were unvaccinated.

A 2013 pertussis outbreak in Florida is a good example that even with all the bad press it gets, the DTaP and Tdap vaccines work too. This outbreak was started by an unvaccinated child at a charter school with high rates of unvaccinated kids. About 30% of unvaccinated kids got sick, while there was only one case “in a person who reported having received any vaccination against pertussis.”

In another 2013 pertussis outbreak in Florida, this time in a preschool, although most of the kids were vaccinated, the outbreak started with “a 1-year-old vaccine-exempt preschool student.” And the classroom with the highest attack rate, was “one in which a teacher with a laboratory-confirmed case of pertussis who had not received a Tdap booster vaccination, worked throughout her illness.”

Why do so many unvaccinated kids get pertussis these days?

“We found evidence of an increase in exemption rates, spatial clustering of nonmedical exemptions, and space-time clustering of pertussis in Michigan. There was considerable overlap between the clusters of exemptions and the clusters of pertussis cases.”

Omer et al on Geographic Clustering of Nonmedical Exemptions to School Immunization Requirements and Associations With Geographic Clustering of Pertussis

Besides the fact that they are unvaccinated and unprotected?

“Children of parents who refuse pertussis immunizations are at high risk for pertussis infection relative to vaccinated children. Herd immunity does not seem to completely protect unvaccinated children from pertussis.”

Glanz et al on Parental refusal of pertussis vaccination is associated with an increased risk of pertussis infection in children.

They can’t get away with hiding in the herd.

Another important consideration – in addition to the fact that more unvaccinated kids get pertussis, when they get pertussis, it is more severe than those who are vaccinated.

“Serious pertussis symptoms and complications are less common among age-appropriate number of pertussis vaccines (AAV) pertussis patients, demonstrating that the positive impact of pertussis vaccination extends beyond decreasing risk of disease.”

McNamara et al on Reduced Severity of Pertussis in Persons With Age-Appropriate Pertussis Vaccination-United States, 2010-2012.

Still thinking of skipping or delaying your child’s pertussis vaccine?

More on Do More Vaccinated or Unvaccinated Kids Get Pertussis?

Can Vaccinated Children Be Asymptomatic Carriers of Pertussis?

Why do anti-vaccine folks like to talk about baboons so much?

“Did you know that a study showed that baboons injected with whooping cough vaccine became infected with whooping cough anyway – and silently spread the disease to other baboons for 35 days?”

Anti-vaccine Meme

Is it because baboons are used in the study of vaccines?

That’s part of it, at least when they can find a study where they can cherry pick the results to suit their needs.

The Baboon Study

Like most anti-vaccine talking points, this one about baboons, has some truth to it.

An adult male baboon.
An adult male baboon. Photo by Elizabeth Miller

There was a baboon study with the pertussis vaccine and it found that previously vaccinated baboons could develop asymptomatic carriage of the pertussis bacteria after they were intentionally infected.

Here is where it is important to note that an infection is different than a disease.

The example that many people are familiar with is tuberculosis. It is common to have a TB infection without any signs or symptoms and to not feel sick. The only reason we know that they have TB is because they had a positive TB test.

Unfortunately, about 5 to 10% of these people with TB infections can eventually develop TB disease, with coughing, weight loss, night sweats, fever, and chest pain, etc.

It is kind of the same with the baboons in the study. Twenty-four hours after two previously vaccinated baboons were inoculated with pertussis bacteria in the back of their nose and trachea, an unvaccinated baboon was put in each of their cages.

The vaccinated baboons continued to have pertussis bacteria in their noses, which the researchers had put there, for up to 35 days. And they were able to eventually pass the pertussis bacteria to the unvaccinated baboons in their cages. Vaccinated baboons also became infected or colonized after they were put in a cage with an intentionally infected unvaccinated baboon.

“…animals did not cough and showed no reduction of activity, loss of appetite, or other outward signs of disease.”

Warfel et al on Acellular pertussis vaccines protect against disease but fail to prevent infection and transmission in a nonhuman primate model

The vaccinated baboons were infected, but they never did develop symptoms of pertussis.

What Does The Baboon Study Mean?

One thing that is for sure – the baboon study found that the pertussis vaccines work. Only unvaccinated baboons got sick with pertussis.

But does this study explain our current outbreaks of pertussis?

Are vaccinated people becoming colonized and then getting others sick?

I guess it is possible, but we are not baboons in a cage with other baboons. How would we spread a respiratory disease, even if we did become colonized with the bacteria, if we don’t have symptoms?

It may explain part of our outbreaks though.

If vaccinated people do commonly become colonized with pertussis bacteria, then they might very well test positive for pertussis even though they don’t have symptomatic pertussis disease. So when they develop a cold or bronchitis and are found to have a positive pertussis test, then couldn’t that test just indicate that they have a pertussis infection and not disease, even though something else is actually causing their symptoms?

That’s what we think happens with strep carriers, right?

That’s kind of what the baboon study found. All of the baboons tested positive, but only the unvaccinated baboons had symptomatic pertussis disease.

“Baboons vaccinated with wP vaccines exhibit a level of protection that is intermediate between convalescent animals and aP-vaccinated animals. They exhibit no outwards signs of disease and are initially colonized to the same high level as aP-vaccinated animals but clear the infection more rapidly.”

Pinto et al on Pertussis disease and transmission and host responses: insights from the baboon model of pertussis.

It is interesting to note that the baboon study also found that baboons who had received whole cell pertussis vaccines also became carriers. They just didn’t stay carriers for as long as the baboons who got the newer acellular pertussis vaccine. But since they were still carriers, if asymptomatic transmission is such a big problem, wouldn’t it have been a big problem back in the day when everyone got whole cell pertussis vaccines?

The Debate Over Asymptomatic Carriage

Most vaccines prevent the spread of disease.

Do the pertussis vaccines?

Most folks still think so.

“The baboon model pioneered by Warfel et al. is without question a game-changer, shedding light on the impact of vaccination on disease and infection. However, the view it affords is clearer with respect to immunity and pathology than with respect to transmission. We point out that the extrapolation of the possibility of transmission from vaccinated baboons in the laboratory to the probability of transmission from vaccinated humans in the population is unwarranted. More work is needed to elucidate the relative transmissibility of infections in vaccinated vs. unvaccinated hosts. The evidence adduced above suggests, however, that vaccination with aP must have a strong effect on transmission as well as disease.”

Matthieu Domenech de Cellès et al on Epidemiological evidence for herd immunity induced by acellular pertussis vaccines

Even the author of the baboon study has said that “We agree that these data should not be directly extrapolated to pertussis transmission in humans. Although baboons are >96% genetically similar to humans, there are likely differences in how the species respond to vaccination and infection. We also agree that aP-vaccinated infected people are likely less efficient at transmitting pertussis compared with unvaccinated infected people, although it is not clear to what extent.”

Others think that asymptomatic carriage of pertussis might behind a lot of our recent outbreaks. Or at least what helps them grow so large.

Still, it is important to remember that unvaccinated folks do play a role in these outbreaks too. In a pertussis outbreak at a Florida preschool, in which most kids were vaccinated, the outbreak was started by a vaccine-exempt toddler.

And we have seen this in many other areas and it has been confirmed by many studies. Whatever else is contributing to pertussis outbreaks, like waning immunity, they are also associated with vaccine refusal.

“Counties with higher exemption rates had higher rates of reported pertussis among exempted and vaccinated children when compared with the low-exemption counties.”

Imdad et al. on Religious exemptions for immunization and risk of pertussis in New York State, 2000-2011.

But what if the DTaP and Tdap vaccines do cause folks to be asymptomatic carriers?

Even if that is true, understand that these vaccines don’t actually infect you, making you a carrier. They just might not prevent you from becoming a carrier if you are exposed to someone else with pertussis. While that might be a good reason to develop a new and better pertussis vaccine, it certainly isn’t a reason to skip or delay your child’s vaccines now.

Remember that even with our current outbreaks, rates of pertussis were much higher in the pre-vaccine era.

What to Know About Vaccines and Asymptomatic Carriers of Pertussis

The role of asymptomatic carriers and pertussis is controversial, but it certainly isn’t a reason to skip or delay your child’s vaccines.

More on the Vaccines and Asymptomatic Carriers of Pertussis