Tag: herd immunity

Why Are the DPT and OPV Vaccines Still Used in Some Countries?

As most folks know, neither the DPT nor OPV vaccines are used in the United States.

Pope Francis helped launch a polio vaccine campaign when he visited Mexico in 2016.
Pope Francis helped launch a polio vaccine campaign when he visited Mexico in 2016.

That they are still used in other countries likely raises some questions for those folks that get them.

Why Are the DPT and OPV Vaccines Still Used in Some Countries?

As I am sure you have guessed, there is no conspiracy about the continued use of these vaccines in other parts of the world. We aren’t getting rid of old stocks of vaccines or using cheaper vaccines in poorer parts of the world.

So what’s the reason?

To understand why they are still used in other countries, it helps to understand why they aren’t used here.

Remember that the DPT vaccine, which protects folks against diphtheria, pertussis, and tetanus, came under attack in the 1970s and 80s as some folks blamed the vaccine for causing vaccine injuries, including seizures and encephalopathy. It didn’t, but we still got a new vaccine, DTaP, which doesn’t seem to work as well.

“Although concerns about possible adverse events following their administration have led to the adoption of acellular pertussis vaccines in some countries, whole-cell pertussis vaccines are still widely produced and used globally in both developed and developing countries. Whole-cell pertussis vaccines that comply with WHO requirements, administered according to an optimal schedule have a long and successful record in the control of whooping cough. Furthermore, the excellent efficacy of some currently available whole-cell pertussis vaccine has also been shown, not only in recent clinical trials, but also on the basis of the resurgence of disease where vaccination has been interrupted or when coverage has markedly decreased. Therefore, WHO continues to recommend whole-cell pertussis vaccines for use in national immunization programmes.”

WHO on Recommendations for whole-cell pertussis vaccine

The WHO now recommends that if countries do switch to DTaP,  the acellular pertussis vaccine, they should be prepared to add additional periodic booster doses and immunizations during pregnancy, which may still “may not be sufficient to prevent resurgence of pertussis.”

The OPV vaccine, on the other hand, was replaced because it can rarely cause vaccine-associated paralytic polio (VAPP) and circulating vaccine-derived polio virus (cVDPV). Of course, it does it at much lower rates than wild polio virus, so until polio is well controlled, the benefit of using OPV outweighs the risk. In addition to being less expensive and easier to use, OPV has the benefit over IPV of providing better herd immunity.

At some point, as we did in the United States in 2000, countries make a switch to the IPV vaccine.

In 2016, remaining countries that use OPV switched from trivalent OPV to bivalent OPV, because wild polio virus type 2 was eradicated in 1999. Once the remaining two types are eradicated, we can stop using the OPV vaccine altogether.

Until then, countries either use:

  • OPV plus one dose of IPV
  • sequential IPV-OPV schedules – high vaccine coverage and low risk of wild polio importation
  • IPV only schedules – sustained high vaccine coverage and very low risk of wild polio importation

So there is no conspiracy. These vaccines are safe and they work.

Without them, there would be over:

  • 1.3 million pertussis related deaths each year
  • 600,000 cases of paralytic polio each year

With most of these cases affecting young children.

More on the Continued Use of DPT and OPV Vaccines

How Contagious Is Measles?

Did you hear about the folks in New York who got quarantined isolated on the Emirates plane from Dubai?

Turns out that about 10 passengers had the flu or other cold viruses.
Although the worry was likely about MERS, it turns out that about 19 passengers had the flu or other cold viruses.

News like that and folks getting exposed to other infectious diseases, probably has them wondering just how contagious these diseases are. Do you have to be sitting next to someone to get them? In the same row? On the same floor?

Understanding Your Risk of Catching a Disease

Fortunately, most diseases are not terribly contagious.

We worry about some things, like SARS and Ebola, because they are so deadly, not because they are so contagious or infectious.

Wait, contagious or infectious? Aren’t they the same thing?

To confuse matters, some infectious diseases aren’t contagious, like Lyme disease. And some vaccine-preventable diseases are neither infectious nor communicable. Think tetanus. You may have never thought of it that way, but you aren’t going to catch tetanus from another person. Of course, that’s not a good reason to skip getting a tetanus shot!

To understand your risk of getting sick, you want to understand a few terms, including:

  • infectious disease – a disease that can be transferred to a new host
  • communicable – an infectious disease that can be transferred from one host to another
  • non-communicable – a non-infectious disease which can not be transferred from one host to another
  • contagiousness – an infectious disease that is easily transferred from one person to another
  • infectivity – the ability of an infectious agent to cause an infection, measured as the proportion of persons exposed to an infectious agent who become infected. Although this doesn’t sound much different from contagiousness, it is. The Francisella tularensis bacteria is highly infectious, for example, to the point that folks exposed to a culture plate are given antibiotics or put on a fever watch. Few of us get tularemia though, because transmission is through tick bites, hunting or skinning infected rabbits, muskrats, prairie dogs and other rodents, or inhaling dust or aerosols contaminated with F. tularensis bacteria. So if you get exposed, you will probably get sick, but there is a low probability for getting exposed.
  • incubation period – the time it takes to start having symptoms after you are exposed to an infectious disease. A longer incubation period increases the chances that someone will get exposed to a disease and travel home before getting sick. A shorter incubation period, like for influenza, means that a lot of people can get sick in a short amount of time.
  • contagious period- the time during which you can spread the illness to other people and may start before you have any symptoms
  • quarantine – used to separate people who have been exposed to a contagious disease and may become sick, but aren’t sick yet
  • isolation – used to separate people who are already sick with a contagious disease
  • transmission – how the disease spreads, including direct (direct contact or droplet spread) vs indirect transmission (airborne, vehicleborne, or vectorborne)
  • R0 (r nought) – the basic reproductive number or the number of new infections originating from a single infectious person among a total susceptible population
  • Rn – the net reproductive number, which takes into account the number of susceptibles in a community
  • infectious period – how long you are contagious

Got all that?

How Contagious Is Measles?

If not, understanding how easily you can get measles should help you understand all of these terms.

Measles is highly contagious, which is likely why all of the Brady kids got sick.
Measles is highly contagious, which is likely why all of the Brady kids got sick.

Measles is highly contagious, with a very high R0 number of 12 to 18.

That’s because:

  • the measles virus can live for up to two hours on surfaces and in the airspace where an infected person coughed or sneezed
  • infected people are contagious for up to four days before they have a rash and even know that they have measles, so expose lots of people even if they get put in isolation once they get diagnosed
  • infected people continue to be contagious for up to four days after the rash appears, so can continue to expose people if they aren’t put in isolation

So you don’t need to have someone with measles coughing in your face to get sick. If they coughed or sneezed at the grocery store, on the bus, or at your doctor’s office and then you entered the same area within two hours, then you could be exposed to the measles virus and could get sick.

Why don’t we see at least 12 to 18 people in each measles outbreak anymore?

That’s easy. The definition for R0 is for a total susceptible population. Most folks are vaccinated and protected, so even if they are around someone with measles, they typically won’t get sick.

Still, up to 90% of folks who aren’t immune and are exposed to measles will catch it. That includes infants too young to be vaccinated, kids too young to be fully vaccinated, and anyone who has a true medical exemption to getting vaccinated.

The measles has a very high R0 is easier to see when you compare it to those of some other diseases

 

Infection R0
Diphtheria 6-7
Ebola 1.5-2.5
Flu 1.4-4
MERS 2-8
Mumps 4.7
Pertussis 5-17
Polio 2-20
RSV 3
SARS 2-5
Smallpox 5-7
Varicella 8-10

Why such a big range for some diseases?

These are estimates and you are more or less contagious at different stages of each illness.

Fortunately, in most cases you can just get vaccinated and protected and don’t have to worry too much about them.

More on the Contagious Periods of Diseases

Catch-Up Immunization Plans for Adults

It isn’t hard to figure out how to catch-up kids when they fall behind on their vaccines.

After all, the CDC publishes catch-up immunizations schedules for both younger kids and teens.

Catch-Up Immunization Plans for Adults

What happens when an unvaccinated adult needs to get caught up?

Adults need vaccines too, especially if they have never been vaccinated before.
Adults need vaccines too, especially if they have never been vaccinated before.

They essentially follow the catch-up immunization plan for teens, with a few exceptions:

Are you an adult that needs to get caught up because you have never been vaccinated, your parents skipped or delayed some vaccines, or you lost your immunization records?

Get caught up! It’s likely easier than you think.

More on Catch-Up Immunization Plans for Adults

Vaccine Signs You Might See at Your Pediatricians Office

Does your pediatrician have any signs or posters up on the doors or walls?

If they do, it is probably just a sign alerting you that flu vaccines are available or a reminder to cover their cough when they are sick.

Or maybe they have some educational posters up to educate parents about the overuse of antibiotics, how to wash your hands, or when to call poison control.

Vaccine Signs You Might See at Your Pediatricians Office

Some pediatricians also have signs and posters about vaccines and vaccine preventable diseases:

Do your kids get a lollipop after their vaccines, or just protection against life-threatening diseases?
Do your kids get a lollipop after their vaccines, or just protection against life-threatening diseases?
Thank vaccines and herd immunity.
Thank vaccines and herd immunity.
Skipping some vaccines? Are you going to say sorry if your kids get a vaccine-preventable disease?
Skipping some vaccines? Are you going to say sorry if your kids get a vaccine-preventable disease?
Does your pediatrician have separate waiting rooms for unvaccinated kids?
Does your pediatrician have separate waiting rooms for unvaccinated kids?
There is no benefit, just extra risks, if you delay your child's vaccines.
There is no benefit, just extra risks, if you delay your child’s vaccines.
Vaccine preventable diseases are just a plane ride away.
Vaccine preventable diseases are just a plane ride away. Get vaccinated before you travel.
Parents of Earth, are your children fully immunized?
Long ago, everyone vaccinated their kids.
Unvaccinated children exposed to measles are quarantined for at least 21 days.
Hopefully you will never see a quarantine sign at your pediatrician’s office.

Got questions about vaccines?

Get your answers before your pediatrician puts up a sign that they are firing all unvaccinated kids.

More Vaccine Signs and Posters

Vaccine Movies and Videos

All of the attention that Robert De Niro gave the movie Vaxxed has many people realizing that there are anti-vaccine movies out there.

Promoted as documentaries, they mostly include the same anti-vaccine ‘experts’ that scare parents away from vaccinating their kids on the Internet.

These types of movies include:

  • Vaxxed
  • The Greater Good
  • Trace Amounts
  • Who Killed Alex Spourdalakis?
  • Bought
  • Man Made Epidemic
  • Sacrificial Virgins
  • The Truth About Vaccines

Most are propaganda, without even a trace amount of truth in them, and should not be used as a research tool to help you make a decision about vaccines.

Vaccine Movies and Documentaries

What about movies to actually help you get educated about vaccines?

Every Last Child takes a look at the fight to end polio in Pakistan.
Every Last Child takes a look at the fight to end polio in Pakistan.

Watch these movies and documentaries:

Have you seen or heard about any of these movies about vaccines?

Vaccine Videos

Just as bad as so-called vaccine documentaries, many of the vaccine videos that you find on You-Tube are also filled with misinformation and propaganda, including many vaccine scare videos.

Where are you Jon Stewart? Measles is still around...
Where are you Jon Stewart? Measles is still around…

Watch the following vaccines videos instead:

Still have questions?

More on Vaccine Movies and Videos

Vaccines While Immunosuppressed

It seems to be a big surprise to many folks, but kids can get most vaccines when they are immunosuppressed. In fact, they sometimes get extra some extra vaccines, like Pneumovax, because the  “incidence or severity of some vaccine-preventable diseases is higher in persons with altered immunocompetence.”

They should also get all of their vaccines if they are around someone who is immunosuppressed.

Surprised?

Vaccines While Immunosuppressed

Which vaccines your kids can get while they are immunosuppressed is going to depend greatly on the reason why they are  immunosuppressed.

Are they getting chemotherapy?

Did they just get a stem cell transplant?

Were they born with a specific immunodeficiency, like X-linked agammaglobulinemia, selective IgA deficiency, severe combined immunodeficiency, or chronic granulomatous disease?

Whatever the reason, they likely won’t get a medical exemption to skip all of their vaccines.

“Killed vaccines will not cause infection in immunodeficient or any other children. The fear of increased community-acquired vaccine-preventable diseases should lead to adherence to and completion of recommended immunization schedules in the community to reinforce herd immunity, such that all vaccine-preventable diseases become exceedingly rare.”

Recommendations for live viral and bacterial vaccines in immunodeficient patients and their close contacts

In most cases, immunocompromised kids can get all inactivated vaccines. It is only live vaccines that could pose a problem. Even then, it depends on the specific immunodeficiency as to whether avoiding live vaccines is necessary.

For example, after chemotherapy and a stem cell transplant, kids can usually get live vaccines.

Your doctors can review the latest guidelines to come up with a safe vaccination plan for your child with an immune system problem. If necessary, consultation with an infectious diseases or immunology specialist can also be helpful.

Don’t overlook other causes of possible immunosuppression when getting vaccinated, like taking daily oral steroids for more than two weeks, certain biologic immune modulators, or other medications like methotrexate, azathioprine, 6-mercaptopurine.

“Limited evidence indicates that inactivated vaccines generally have the same safety profile in immunocompromised patients as in immunocompetent individuals. However, the magnitude, breadth, and persistence of the immune response to vaccination may be reduced or absent in immunocompromised persons.”

2013 IDSA Clinical Practice Guideline for Vaccination of the Immunocompromised Host

And keep in mind that just because they can and should get vaccinated, it doesn’t mean that their vaccines are going to work as well as in someone who isn’t immunocompromised.

That’s why herd immunity is so important for these kids.

Vaccines for Close Contacts of Immunocompromised People

What about people who come into contacts with kids and adults who are immunocompromised?

Can they get vaccines?

“Close contacts of patients with compromised immunity should not receive live oral poliovirus vaccine because they might shed the virus and infect a patient with compromised immunity. Close contacts can receive other standard vaccines because viral shedding is unlikely and these pose little risk of infection to a subject with compromised immunity.”

Recommendations for live viral and bacterial vaccines in immunodeficient patients and their close contacts

Yes, close contacts can get vaccinated, especially since we don’t use the oral polio vaccine in the United States anymore.

There are some exceptions for the smallpox vaccine, which few people get, and Flumist, but only in very specific situations, including a recent hematopoietic stem cell transplant.

Johns Hopkins Medicine, which includes the Johns Hopkins University School of Medicine and the The Johns Hopkins Hospital and Health System went out of their way to correct this anti-vaccine misinformation.
Johns Hopkins Medicine, which includes the Johns Hopkins University School of Medicine and the The Johns Hopkins Hospital and Health System went out of their way to correct this anti-vaccine misinformation.

Worried about shedding?

You should be worried about getting a vaccine-preventable disease and giving it to those around you with immune system problems. That’s the real risk!

This is the modern anti-vaccine movement - taking an immoral stand against vaccines and putting sick kids at risk for life-threatening disease.
This is the modern anti-vaccine movement – scaring parents and taking an immoral stand against vaccines and putting sick kids at risk for life-threatening disease.

And no, you are not being selfish to expect those around you to get vaccinated.

Vaccines are safe and necessary – for all of us.

More on Vaccines While Immunosuppressed

Personal Stories About Vaccine-Preventable Diseases

Parents these days seem to get bombarded with vaccine injury stories and videos on Facebook.

Is that because vaccines cause so many bad reactions?

Of course not.

It’s because some folks think that everything that happens to their kids is a vaccine injury.

Personal Stories About Vaccine-Preventable Diseases

If you are going to watch those videos and listen to their stories, getting scared in the process, be sure to also listen to the stories of parents who’s kids have suffered through actually getting a vaccine-preventable disease.

While it’s great that these diseases are much less common because most people vaccinate and protect their kids, one side effect of that progress is that we don’t have many reminders of just how terrible these diseases are anymore.Have you ever seen a baby with congenital rubella syndrome?

Or a child with tetanus or diphtheria?

Have you ever even seen photos of these diseases?

Will you read these stories of parents who have lost a child to a vaccine-preventable disease.

“Kimberly Coffey was buried three days before her high school graduation in the prom dress she didn’t get to wear. She didn’t have the opportunity to be vaccinated against Meningitis B.”

Kim’s Meningitis Story

In Kimberly‘s case, the Men B vaccine wasn’t yet available, but in many other cases, parents have shared their stories of unvaccinated children who suffered with a disease that was vaccine preventable at the time.

“From 2010 to 2016, young children continued to be at the greatest risk for influenza-associated pediatric deaths. Children without preexisting medical conditions accounted for half of all deaths. Vaccination coverage was low among influenza-associated pediatric deaths.”

Shang et al. on Influenza-Associated Pediatric Deaths in the United States, 2010–2016

Tragically, there are also many flu stories.

But the flu isn’t the only vaccine-preventable disease that still harms children.

This family didn't have a choice about their son getting sick - he was too young to be vaccinated when he was exposed to an unvaccinated child with measles.
This family didn’t have a choice about their son getting sick – he was too young to be vaccinated when he was exposed to an unvaccinated child with measles

There are other diseases. Other stories.

Read these stories.

Listen to these parents.

Are the stories supposed to scare you into vaccinating your kids?

Of course not. Just like you shouldn’t let the myths and propaganda from the anti-vaccinate movement scare you away from vaccinating and protecting your kids.

Instead of being motivated by fear, you should make your decision because you understand that the many benefits of vaccines are far greater than their small risks.

What to Know About Vaccine-Preventable Disease Stories

Reading stories of vaccine-preventable diseases are a good reminder that these diseases are not so mild as some folks suggest, and they are instead life-threatening diseases that are best avoided by getting fully vaccinated.

More Vaccine-Preventable Disease Stories