Tag: natural immunity

Dengvaxia for Dengue Fever

Dengvaxia was recently approved by the FDA after being available in other countries since about 2015.

“Indicated for the prevention of dengue disease caused by dengue virus serotypes 1, 2, 3 and 4. DENGVAXIA is approved for use in individuals 9 through 16 years of age with laboratory-confirmed previous dengue infection and living in endemic areas.”

Wait.

Dengue is endemic throughout the tropics and subtropics, including most of the Caribbean.
Dengue is endemic throughout the tropics and subtropics, including most of the Caribbean.

It’s only for people who have already had a dengue infection before?

Dengvaxia Controversy

Unfortunately, Dengvaxia “performs differently in seropositive versus seronegative individuals.”

“In areas of 70% dengue seroprevalence, over a 5-year follow-up, for every 4 severe cases prevented in seropositive, there would be one excess severe case in seronegative per 1,000 vaccinees; for every 13 hospitalizations prevented in seropositive vaccinees, there would be 1 excess hospitalization in seronegative vaccinees per 1,000 vaccinees.”

WHO on Questions and Answers on Dengue Vaccines

If you have never had dengue before and you are vaccinated, you are at risk for a severe infection if you do get dengue. On the other hand, if you are unvaccinated, you are at even greater risk of getting dengue, a life-threatening infection. Fortunately, the first episode of dengue is usually fairly mild.

The problem occurs if your antibody levels have dropped enough, which can cause you to have a severe case of dengue the second time. The process is called antibody-dependent enhancement and has to do with antibody levels, either natural or vaccine induced. So it can occur whether or not you are vaccinated, although getting Dengvaxia, an attenuated, live vaccine, can act as a primary dengue infection.

“These differing epidemiological features support the conclusion that antibody dependent enhanced (ADE) dengue disease occurred in seronegatives who were sensitized by vaccine. As hospitalizations continue to occur in all age groups Dengvaxia consumers should be warned that sensitized vaccinated seronegatives will experience enhanced dengue disease into the forseeable future.”

Scott Halstead on Dengvaxia sensitizes seronegatives to vaccine enhanced disease regardless of age.

It is something that dengue researcher Scott Halstead warned folks about as soon as he saw the first published study on Dengvaxia.

But why would you need a vaccine if you have already had dengue?

“In humans recovery from infection by one dengue virus provides lifelong immunity against that particular virus serotype. However, this immunity confers only partial and transient protection against subsequent infection by the other three serotypes of the virus. Evidence points to the fact that sequential infection increases the risk of developing severe dengue.”

WHO on Dengue control

There are four serotypes of dengue.

So if you aren’t vaccinated, you are at risk to get dengue multiple times.

Tragically, about 800,000 children in the Philippines were given Dengvaxia in a universal immunization program without checking to see if they had dengue first. And it likely led to some severe cases of dengue and deaths. This led to the vaccine being banned in that country and is thought to be one of the causes behind their current measles outbreak, as their Dengvaxia controversy led to more vaccine hesitancy.

And it will lead to more folks getting dengue. Instead of a ban, they should likely be more picky about who they give the vaccine to, either confirming that recipients have already had dengue (titer test) or only giving the vaccine to older kids.

Dengvaxia for Dengue Fever

Do you need Dengvaxia?

Remember, Dengvaxia is only for those living in endemic areas and in the United States, dengue is only endemic in the U.S. territories of American Samoa, Guam, Puerto Rico, and the U.S. Virgin Islands.

Do you need Dengvaxia if you are simply traveling to one of these areas?

Since Dengvaxia is not approved for those who haven’t had a dengue infection before, you likely wouldn’t get it just for traveling to an endemic area, unless perhaps you routinely travel to an endemic area and have had dengue already. A titer test can confirm a previous dengue infection, but there is no indication to get vaccinated for travel yet.

Also, while in other countries it is available for use between 9 and 45 years, in the United States, Dengvaxia is only approved for children between 9 and 16 years of age.

More on Dengvaxia for Dengue Fever

Should I Stop Calling Chickenpox and Measles Diseases?

Sherri Tenpenny wants us to stop calling chickenpox and measles diseases.

She thinks that we should call them infections instead…

Should I Stop Calling Chickenpox and Measles Diseases?

If you are like most people, you are probably thinking to yourself and maybe even shouting at your computer screen right now, “who cares what you call them, just get vaccinated and stop the outbreaks!”

When you vaccinate to avoid an infection, what you are potentially doing is preventing a death!
When you vaccinate to avoid an infection, what you are potentially doing is preventing a death!

Believe it or not, there is actually some precedent for changing the way we talk about diseases. While you may still refer to them as STDs, or sexually transmitted diseases out of habit, the prefererable term is actually STI, or sexually tranmistted infection.

Of course, this has nothing to do with Tenpenny’s reasoning.

“Why the change? The concept of ‘disease,’ as in STD, suggests a clear medical problem, usually some obvious signs or symptoms. But several of the most common STDs have no signs or symptoms in the majority of persons infected. Or they have mild signs and symptoms that can be easily overlooked. So the sexually transmitted virus or bacteria can be described as creating ‘infection,’ which may or may not result in ‘disease.’ This is true of chlamydia, gonorrhea, herpes, and human papillomavirus (HPV), to name a few.

For this reason, for some professionals and organizations the term ‘disease’ is being replaced by ‘infection.'”

ASHA on STDs/STIs

In fact, their definitions sound nothing like Tenpennys…

Unfortunately, many STIs, even if they aren’t causing symptoms and disease, can still be contagious.

Measles and chickenpox don’t do that. Although you can be contagious just before you start to have symptoms, you will very quickly develop symptoms.

It is true that some viruses and bacteria can lead to subclinical infections, in which you develop immunity without ever developing symptoms, but that doesn’t usually happen with measles and chicken pox.

Polio is one of the best examples of when it does happen. Remember, nearly 75% of kids who got polio never had any symptoms. Tragically, those symptoms could be severe in the small percentage who did.

So as usual, Sherri Tenpenny is wrong.

Chickenpox and measles are infections that cause disease. And while most people recover after 7 to 10 days of symptoms, including a high fever and rash, some don’t.

Both also put you at risk for long-term complications, namely shingles and SSPE.

Remember, if you listen to folks like her and skip or delay your child’s vaccines and they get chickenpox or measles, the only thing you are doing is causing more people to get sick. A catchy slogan won’t prevent that or keep your kids healthy.

More on Diseases vs Infections

Can Vaccines Cause Rhabdomyolysis?

The urine is dark because of myoglobinuria secondary to muscle break down. Hemoglobinuria, from blood, is the other thing that makes urine dark.
The urine is dark because of myoglobinuria secondary to muscle break down. Hemoglobinuria, from blood, is the other thing that makes urine dark. Photo Kumar et al (CC BY-NC-SA 3.0 US).

You have probably never heard of rhabdomyolysis.

Children with rhabdomyolysis have severe muscle pain, muscle weakness, and dark urine.

It is classically caused by exercising too much (really overdoing it or exercising a lot more or a lot longer than you typically do) and damaging your muscles, leading to a breakdown of muscle cells and the release of creatine kinase, which in addition to muscle symptoms, can lead to kidney failure.

In addition to exercise, rhabdomyolysis can be caused by seizures, drugs, toxins, insect stings, snake bites, metabolic disorders, infections (viral myositis), and trauma.

“The most common causes of pediatric rhabdomyolysis were viral myositis (38%), trauma (26%), and connective tissue disease (5%).”

Mannix et al on Acute Pediatric Rhabdomyolysis: Causes and Rates of Renal Failure

Keep in mind that rhabdomyolysis is rare. You won’t confuse the aches and pains that most kids get, and which often get blamed on growing pains, with rhabdomyolysis. Although younger kids don’t always have dark urine when they have rhabdo, the pain and weakness is severe. Seek immediate medical attention if you think that your child might have rhabdomyolysis.

Can Vaccines Cause Rhabdomyolysis?

It is well known that rhabdomyolysis can be caused by infections.

“Rhabdomyolysis has been reported to be associated with a variety of viral infections, including influenza, [15,16] Coxsackie virus, human immunodeficiency virus (HIV), echovirus and cytomegalovirus [17]. In our series, the definite viral infection was identified in 5 patients (influenza type B in 4, Coxsackie A10 in 1)”

Chen et al on Clinical spectrum of rhabdomyolysis presented to pediatric emergency department

So if a natural influenza virus infection can cause rhabdomyolysis, does that mean that the flu vaccine can too? What about other vaccines?

Not necessarily, but there are a few case reports that associate vaccines with rhabdomyolysis.

“Influenza A infection has been described as a major viral cause of infection-induced rhabdomyolysis, but to date, only one reported case was described as having been induced by influenza vaccine.”

Callado et al on Rhabdomyolysis secondary to influenza A H1N1 vaccine resulting in acute kidney injury.

In several of the reports, patients already had chronic medical problems for which they were being treated. Still, no signal was found to suggest that the flu vaccine is a problem for these patients.

It is important to note that reports of post-vaccination rhabdomyolysis in healthy people are even rarer.

So while it is could be possible that vaccines are rarely associated with rhabdomyolysis, we know that many infections, including many vaccine-preventable diseases, are a more common cause.

Don’t skip or delay a vaccine because you might have heard that vaccines cause rhabdomyolysis.

Vaccines are safe, with few risks, and are obviously necessary.

More on Vaccines and Rhabdomyolysis

Who Gets SSPE?

Have you heard that you can get SSPE from the MMR?

Apparently it’s in the vaccine insert…

Who Gets SSPE?

Subacute sclerosing panencephalitis (SSPE) occurs after a natural measles infection.

You won't get SSPE if you don't get measles.

It is not caused by MMR or any measles containing vaccine.

Of course, the measles vaccine is not 100% effective, so it is possible that you could still get measles after being vaccinated. And those folks who get measles after getting vaccinated could be at risk to get SSPE, but even then, their SSPE would be caused by wild measles virus, not a vaccine strain.

“Available epidemiological data are consistent with a directly protective effect of vaccine against SSPE mediated by preventing measles.”

Subacute sclerosing panencephalitis and measles vaccination

Again, SSPE is caused by natural measles infections and the wild type measles virus.

Tragically, after big outbreaks of measles, we start to see more cases of SSPE, with the greatest in children who get measles at a young age.

And SSPE is universally fatal in these children, who develop symptoms about six to eight years after recovering from having measles.

That the symptoms of SSPE don’t develop until long after you have recovered from measles is why the condition is often described as a time-bomb.

A time-bomb that you can’t stop.

Want to avoid getting SSPE? Get vaccinated and protected against measles.

More on Getting SSPE