Category: Vaccines

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

The Shingles Vaccine Shortage

Shingrix became the second shingles vaccine to be licensed in the United States, becoming the preferred shingles vaccine in 2017.

“Shingrix provides strong protection against shingles and PHN. Two doses of Shingrix is more than 90% effective at preventing shingles and PHN. Protection stays above 85% for at least the first four years after you get vaccinated.”

What Everyone Should Know about Shingles Vaccine

The first, Zostavax, was licensed in 2006.

Both are for older adults.

The Shingles Vaccine Shortage

Having a new and better shingles vaccine is good!

High levels of demand for shingles vaccine has lead to shortages and Shingrix manufacturing facilities are already at maximum capacity.
High levels of demand for shingles vaccine has lead to shortages and Shingrix manufacturing facilities are already at maximum capacity.

Not being able to actually get the vaccine and get vaccinated and protected isn’t so good. There has been a shortage of the vaccine due to high levels of demand since last year.

“Recombinant zoster vaccine (RZV) is recommended for the prevention of herpes zoster and related complications for immunocompetent adults aged ≥50 years.”

Recommendations of the Advisory Committee on Immunization Practices for Use of Herpes Zoster Vaccines

Fortunately, we will likely see more doses of the vaccine available this year and everyone will eventually be able to get vaccinated. In addition to your doctor or favorite pharmacy, the Shingrix Vaccine Locator might help you find a dose until the shortage is over.

More on the Shingles Vaccine Shortage

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

Everything You Need to Know About the Measles Vaccine

The measles vaccine is one of the most effective vaccines we have.

It is also one of the safest, having very few serious side effects.

Everything You Need to Know About the Measles Vaccine

So why are some parents still afraid to allow their kids to get vaccinated and protected, putting them at risk to get measles, a life-threatening disease?

“Existing evidence on the safety and effectiveness of MMR vaccine supports current policies of mass immunisation aimed at global measles eradication and in order to reduce morbidity and mortality associated with mumps and rubella.”

Cochrane Systematic Review on Vaccines for measles, mumps and rubella in children

Let’s see if you still are after we get all of your questions about the measles vaccine answered…

Schools in California were closed for at least two weeks in 1917 because of measles epidemics.
Schools in California were closed for at least two weeks in 1917 because of measles epidemics.
  1. How long has the measles vaccine been around? The very first measles vaccine was licensed by John Enders in 1963. An improved measles vaccine was developed by Maurice Hilleman and licensed in 1968, and that is the measles vaccine that we still use today, at least in the United States. It was combined into the MMR vaccine in 1971.
  2. How effective is the measles vaccine? A single dose of the measles vaccine is about 93% effective at preventing a measles infection. Two doses (the second dose was added to the routine immunization schedule in 1994) are up to 97% effective. That’s why almost all of the people who get measles in an outbreak are unvaccinated.
  3. How long does immunity from the measles vaccine last? Immunity from the measles vaccine is thought to be life-long. It is important to understand that the second dose isn’t a booster dose, but is instead for those few folks who don’t respond to the first dose.
  4. Who should get the measles vaccine? Everyone without a true medical contraindication should get the measles vaccine (MMR), with the first dose at 12-15 months and a second dose at 4-6 years.
  5. Can my kids get their measles vaccine early? An advanced immunization schedule is available for kids in an outbreak or if they will be traveling out of the country. The first dose can be given as early as age 6-months, but is repeated when the child is 12 months because of concerns of interference with maternal antibodies. The official second dose can be given early too, as early as 4 weeks after the first dose, as long as the child is at least 12 months old.
  6. Do I need a booster dose of the measles vaccine? People who are fully immunized do not need a booster dose of the MMR vaccine, but it is important to understand whether or not you are really fully immunized to see if you need a second dose. Some adults who are not high risk are considered fully vaccinated with only one dose, while others should have two doses. Are you at high risk to get measles? Do you travel, live in an area where there are measles outbreaks, go to college, or work as a health care professional?
  7. Should I check my measles titers? In general, it is not necessary to check your titers for measles. If you haven’t had two doses of the MMR vaccine, then get a second dose. If you have had two doses of the MMR vaccine, then you are considered protected. Keep in mind that there is no recommendation to get a third dose of MMR for measles protection, although it is sometimes recommended for mumps protection during a mumps outbreak.
  8. If my child gets a rash after getting his MMR, does that mean that he has measles? No. This is a common, very mild vaccine reaction and not a sign of measles.
  9. Can the measles vaccine cause seizures? The MMR vaccine can cause febrile seizures. It is important to remember that without other risk factors, kids who develop febrile seizures after a vaccine are at the same small risk for developing epilepsy as other kids. And know that vaccines aren’t the only cause of febrile seizures. Vaccine-preventable diseases can cause both febrile seizures and more serious non-febrile seizures.
  10. Why do people think that that the measles vaccine is associated with autism? It is well known that this idea originated with Andrew Wakefield, but the real question should be why do some people still think that vaccines are associated with autism after so much evidence has said that they aren’t?
  11. What are the risks of the measles vaccine? Like other vaccines, the MMR vaccine has mild risks or side effects, including fever, rash, and soreness at the injection site. Some more moderate reactions that can rarely occur include febrile seizures, joint pain, and a temporary low platelet count. More serious reactions are even rarer, but can include deafness, long-term seizures, coma, or lowered consciousness, brain damage, and life-threatening allergic reactions.
  12. Why are there so many reports of measles vaccine deaths? There are extremely few deaths after vaccines. The reports of measles vaccine deaths you see on the Internet are just reports to VAERS and are not actually reports that have been proven to be caused by a vaccine. As with other vaccines, the risks from having a vaccine-preventable disease are much greater than the risks of the vaccine. The only reason that it might not seem like that now is because far fewer people get measles now than they did in the pre-vaccine era, when about 500 people died with measles each year.
  13. When did they take mercury out of the measles vaccine? Measles vaccines, including the MMR, have never, ever contained mercury or thimerosal.
  14. Why do we still have outbreaks if we have had a measles vaccine since 1963? In the United States, although the endemic spread of measles was declared eliminated in 2000, many cases are still imported from other countries. As measles cases increase around the world, that is translating to an increase in outbreaks here. Even though overall vaccination rates are good, because there are many pockets of susceptible people in areas that don’t vaccinate their kids, they get hit with outbreaks.
  15. Can we eradicate measles? Because measles is so contagious, the vaccine does have failures, and some folks still don’t get vaccinated, there is some doubt that we can eradicate measles without a better vaccine. That doesn’t mean that the current measles vaccines can’t prevent outbreaks though…

Are you ready to get your kids their MMR vaccine so that they are vaccinated and protected against measles, mumps, and rubella?

If not, what other questions do you have?

While you are thinking, here is a question for you – Do know why they used to call measles a harmless killer?

More on the Everything You Need to Know About the Measles Vaccine

Does Pentacel Contain Mercury?

Thimerosal was taken out of most childhood vaccines in 2001, only remaining in muti-dose vials of flu vaccines, which could easily be avoided, as a good supply of thimersosal-free flu vaccine has been available for many years.

“Thimerosal is a mercury-based preservative that has been used for decades in the United States in multi-dose vials (vials containing more than one dose) of medicines and vaccines. There is no evidence of harm caused by the low doses of thimerosal in vaccines, except for minor reactions like redness and swelling at the injection site. However, in July 1999, the Public Health Service agencies, the American Academy of Pediatrics, and vaccine manufacturers agreed that thimerosal should be reduced or eliminated in vaccines as a precautionary measure.”

CDC on Thimerosal in Vaccines

For some reason, that hasn’t kept some parents from still being concerned about mercury in vaccines.

Does Pentacel Contain Mercury?

Pentacel is vaccine that combines the diphtheria and tetanus toxoids and acellular pertussis adsorbed, inactivated poliovirus and Haemophilus b conjugate (tetanus toxoid conjugate) vaccines (DTaP-IPV/Hib) into one shot.

Pentacel is mercury free.
Like most other vaccines on the childhood immunization schedule, Pentacel is mercury free.

It is routinely given to children as a four dose series, when they are 2, 4, 6, and 15 to 18 months old.

Like most other vaccines given to children, Pentacel is thimerosal-free.

It does not contain mercury.

More on Mercury in Vaccines

Can You Still Get Shingles After Having the Chicken Pox Vaccine?

It is very easy to get confused when thinking or talking about chicken pox and shingles.

Remembering a few things should help though:

  • shingles (herpes zoster) is a reactivation of chicken pox (varicella zoster) – since they are caused by the same virus, you had to have been exposed to the chicken pox virus (varicella zoster virus) to later get shingles
  • exposure to the chicken pox virus can come from a natural chicken pox infection or from getting vaccinated against chicken pox, as it is a live, attenuated vaccine (Varivax)

So no, getting the chicken pox vaccine will not prevent you from later getting shingles. The shingles vaccine is a different vaccine that is given to seniors to help prevent them from getting shingles.

Can You Still Get Shingles After Having the Chicken Pox Vaccine?

Have you ever heard of a child vaccinated against chicken pox getting shingles? It can happen. It’s not a vaccine injury.

Remember that you can get shingles at any age – it is not just a disease of senior citizens. Even preschools or teens can get shingles, with the risk increasing with age.

Although rare, even infants can develop shingles, most commonly if their mothers had a chicken pox infection while pregnant.
Although rare, even infants can develop shingles, most commonly if their mothers had a chicken pox infection while pregnant. Photo by Kaoutar Zinelabidine et al.

Although the chicken pox vaccine won’t prevent you from getting shingles, it does work well to prevent you from getting chicken pox.

And it is thought that getting vaccinated and protected against chicken pox will decrease your risk of later getting shingles, even before you ever get the shingles vaccine.

“In the early post-varicella vaccination period, incidence rates of medically attended herpes zoster did not increase for the overall population and decreased moderately for children 9 years and younger, the age group targeted for varicella vaccination.”

Tanuseputro et al on Population-based incidence of herpes zoster after introduction of a publicly funded varicella vaccination program

No chicken pox and a lower risk of shingles?

I’m glad my kids are fully vaccinated!

More on Shingles and the Chicken Pox Vaccine

Are You Ready for DNA Vaccines?

Believe it or not, vaccines aren’t a one-size-fits-all kind of a thing.

“There are several different types of vaccines. Each type is designed to teach your immune system how to fight off certain kinds of germs — and the serious diseases they cause.”

Vaccine Types

In addition to live vaccines, like MMR, there are inactivated vaccines, toxoid vaccines, and subunit, recombinant, polysaccharide, and conjugate vaccines.

Are You Ready for DNA Vaccines?

Vaccines made with current technology have helped save millions of lives.

It’s time for some new approaches though, especially as we are seeing the limitations of some of our current vaccines, especially the seasonal flu vaccine.

“DNA vaccines take immunization to a new technological level. These vaccines dispense with both the whole organism and its parts and get right down to the essentials: the microbe’s genetic material. In particular, DNA vaccines use the genes that code for those all-important antigens.”

NIH on Vaccine Types

While a DNA vaccine might sound like something out of the 23rd century, researchers have been studying them since the 1990s.

“Researchers have found that when the genes for a microbe’s antigens are introduced into the body, some cells will take up that DNA. The DNA then instructs those cells to make the antigen molecules. The cells secrete the antigens and display them on their surfaces. In other words, the body’s own cells become vaccine-making factories, creating the antigens necessary to stimulate the immune system.”

NIH on Vaccine Types

Does the idea of being injected with the genes for a microbe’s antigens scare you?

“The original concerns associated with the DNA platform were the potential for genomic integration and development of anti-DNA immune responses. Exhaustive research has found little evidence of integration, and the risk for integration appears to be significantly lower than that associated with naturally occurring mutations”

Ferraro et al on Clinical Applications of DNA Vaccines: Current Progress

What do you think happens when you get the flu?

The flu virus and it’s DNA is taken up by your cells, and those cells then start making more flu proteins.

“This approach offers a number of potential advantages over traditional approaches, including the stimulation of both B- and T-cell responses, improved vaccine stability, the absence of any infectious agent and the relative ease of large-scale manufacture.”

WHO on DNA Vaccines

So where are all of the DNA vaccines?

“However, the results of these early clinical trials were disappointing. The DNA vaccines were safe and well tolerated, but they proved to be poorly immunogenic. The induced antibody titers were very low or nonexistent, CD8+ T-cell responses were sporadic, and CD4+ T-cell responses were of low frequency. However, these studies provided proof of concept that DNA vaccines could safely induce immune responses (albeit low-level responses) in humans.”

Ferraro et al on Clinical Applications of DNA Vaccines: Current Progress

After getting disappointing results in the 1990s, researchers have since moved on to second-generation DNA vaccines, which are being tested for HIV treatment and prevention, Zika, Dengue fever, influenza (DNA vaccine prime), HPV, cancer treatment (metastatic breast, B cell lymphoma, melanoma, prostate, colorectal), chronic hepatitis B treatment, chronic hepatitis C treatment, herpes, and malaria.

There are many completed trials for DNA vaccines.
There are already many completed trials for DNA vaccines.

While many of these DNA vaccines are now in phase I and II trials, unfortunately, that means we are still a long time away from having a DNA vaccine on the immunization schedule.

More on DNA Vaccines