Category: Vaccines

Why Do You Need to Get a Flu Vaccine Each Year?

A yearly flu vaccine is the best way to protect yourself and your family against the flu.

But why do you need to get a flu vaccine each and every year?

Why Do You Need to Get a Flu Vaccine Each Year?

Hopefully we will one day have a universal flu vaccine that covers all flu strains and offers longer lasting protection.

Most folks know we don’t have that flu vaccine yet…

“A flu vaccine is needed every season for two reasons. First, the body’s immune response from vaccination declines over time, so an annual vaccine is needed for optimal protection. Second, because flu viruses are constantly changing, the formulation of the flu vaccine is reviewed each year and updated as needed to keep up with changing flu viruses. For the best protection, everyone 6 months and older should get vaccinated annually.”

CDC on Key Facts About Seasonal Flu Vaccine

So because the protection from the flu vaccine wanes or wears off relatively quickly, even if the flu vaccine strains don’t change from one year to the next, you should get a new flu vaccine.

How long does the protection from the flu vaccine last?

“An analysis from the 2011–12 through 2013–14 seasons noted protection ranging from 54% to 67% during days 0 through 180 postvaccination.”

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season

The flu vaccines takes about two weeks to become effective and should then last for at least six months – long enough to get  you through the average flu season.

“A number of observational studies and a post hoc analysis from a randomized controlled trial have reported decreases in vaccine effectiveness (VE) within a single influenza season, with increasing time postvaccination. Waning effects have not been observed consistently across age groups, virus subtypes, and seasons; and observed declines in protection could be at least in part attributable to bias, unmeasured confounding, or the late season emergence of antigenic drift variants that are less well-matched to the vaccine strain. Some studies suggest this occurs to a greater degree with A(H3N2) viruses than with A(H1N1) or B viruses . This effect might also vary with recipient age; in some studies waning was more pronounced among older adults and younger children. Rates of decline in VE have also varied.”

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices—United States, 2018–19 Influenza Season

That means it should last past the peak of the average flu season, which is typically between December and March.

And in most young, healthy people, the protection likely lasts even longer.

Make sure you are vaccinated well before flu season starts.
Make sure you are vaccinated well before flu season peaks, which since 1982 has occurred as early as October and as late as March, but is most common in February.

Still, there is some concern that the protection from the flu vaccine can wear off during a flu season, especially if you are very young, very old, or have chronic medical problems, and you get your flu vaccine early and you get exposed late – in April or May.

Of course, that’s not a good reason to delay getting a flu vaccine though, as waiting too long might leave you unprotected if flu peaks early, in October or November.

What to Know About Why You Need the Flu Vaccine Every Year

Since the flu vaccine strains can change and protection doesn’t last from season to season, get a flu vaccine each year. It’s the best way to protect yourself and your family against the flu.

More on Why You Need the Flu Vaccine Every Year

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

Why Isn’t There a Vaccine for Leprosy?

Why do anti-vaccine folks talk about leprosy (Hansen’s disease) so much?

“LEPROSY. I’m curious why there isn’t a vaccine for leprosy. With all the other bazillion vaccines out there, why not one for leprosy?”

We don’t have anywhere near a bazillion vaccines, but did you know that there actually is a vaccine for leprosy?

“Why aren’t you walking around concerned about leprosy every day? Why aren’t you concerned about someone from another country bringing leprosy into Australia or the US and somehow exposing all of our most vulnerable to this illness? I’ll tell you why. Because there’s no vaccine for leprosy. You are afraid of what we vaccinate for because these illnesses are hyped up all of the time. It’s propaganda. ”

Learn the Risk – Why aren’t we afraid of all diseases?

Don’t expect the leprosy vaccine to be added to our immunization schedule any time soon or to increase your fears about leprosy, as leprosy is not highly contagious and it can be treated, and even cured.

And while there are about 150 to 250 cases in the United States each year, most are in folks who used to live in areas of the world where leprosy is more common. Unlike measles, you aren’t likely to get leprosy at school or daycare or going to Disneyland, although you could get it if you have a pet armadillo.

Leprosy Vaccines

A vaccine against leprosy is important though. As with other diseases, we are seeing multi-drug resistant forms of Mycobacterium leprae, the bacteria that causes leprosy.

The new leprosy vaccine that is being developed will hopefully help to finally eliminate leprosy in parts of the Africa, Asia and Latin America where it is still a problem.

Throughout much of the 20th Century, people with leprosy in the United States were treated at the National Leprosarium in Carville, Louisiana.
Throughout much of the 20th Century, people with leprosy in the United States were treated at the National Leprosarium in Carville, Louisiana.

But it isn’t the first leprosy vaccine that we will have had.

Various leprosy vaccines have been developed and tested since the 1980s.

Also, the M. bovis BCG vaccine has been known to provide protection against both Mycobacterium tuberculosis (tuberculosis) and the related Mycobacterium leprae (leprosy) since as early as 1939.

“BCG vaccination is recommended in countries or settings with a high incidence of TB and/or high leprosy burden.”

BCG vaccines: WHO position paper – February 2018

The new leprosy vaccine, a sub-unit vaccine, will hopefully be more effective than previous strategies though, and will work to both prevent and treat leprosy.

Another leprosy vaccine, Mycobacterium indicus pranii (MIP), is being developed and tested in India.

Still, leprosy will never be eradicated, as armadillos serve as an animal reservoir for the Mycobacterium leprae  bacteria.

What to Know About Leprosy Vaccines

At least two leprosy vaccines are being developed and tested to help eliminate leprosy from the areas of Africa, Asia and Latin America where it is still a problem.

More on Leprosy Vaccines

Understanding the Recommendations to Get a Men B Vaccine

A lot of folks, even some pediatricians, are still confused about the recommendations for the meningococcal B vaccines.

Remember, two vaccines, Bexsero and Trumenba, are approved to protect against serogroup B meningococcal disease.

The Men B Vaccine for High Risk Kids

There is no confusion about the recommendation that high risk kids should get vaccinated against meningococcal B disease.

“Certain persons aged ≥10 years who are at increased risk for meningococcal disease should receive MenB vaccine.”

ACIP on Use of Serogroup B Meningococcal Vaccines in Persons Aged ≥10 Years at Increased Risk for Serogroup B Meningococcal Disease: Recommendations of the Advisory Committee on Immunization Practices, 2015

Who’s high risk?

In addition to microbiologists who work with the Neisseria meningitidis bacteria, you are considered to be high risk if you are at least 10 years old and:

  • MenB vaccines are routinely given during outbreaks on college campuses.
    MenB vaccines are routinely given during outbreaks on college campuses.

    have a persistent complement component deficiency, including inherited or chronic deficiencies in C3, C5–C9, properdin, factor D, or factor H

  • have anatomic or functional asplenia, including sickle cell disease, children with congenital asplenia, and children who’s spleen was removed (splenectomy) to prevent complications of other conditions, such as ITP, hereditary spherocytosis, pyruvate kinase deficiency, Gaucher disease, and hypersplenism, etc.
  • are taking the medication eculizumab (Soliris), which is used to treat two rare blood disorders, atypical hemolytic uremic syndrome (aHUS) and paroxysmal nocturnal hemoglobinuria (PNH)
  • could be exposed in a serogroup B meningococcal disease outbreak

And, if high risk, you should either get a 3 dose series of Trumenba or a 2 dose series of Bexsero.

Keep in mind that traveling is not usually a risk factor for Men B, but can be for the other meningococcal vaccines.

The Men B Vaccine for Healthy Teens

But what if you aren’t at high risk?

While teens should routinely get vaccinated with other meningococcal vaccines, Menactra or Menveo, that provide protection against serogroups A, C, W, Y,  the recommendation for Men B vaccination is more permissive.

“A MenB vaccine series may be administered to adolescents and young adults aged 16–23 years to provide short-term protection against most strains of serogroup B meningococcal disease. The preferred age for MenB vaccination is 16–18 years.”

ACIP on Use of Serogroup B Meningococcal Vaccines in Adolescents and Young Adults: Recommendations of the Advisory Committee on Immunization Practices, 2015

When given to healthy teens who are not at high risk for meningococcal disease, both Bexsero and Trumenba can be given as a two dose series.

A Permissive Recommendation for Men B Vaccines

This permissive recommendation for Men B is what has got folks confused…

“The recommendation is labeled as “Category B,” meaning that individual clinical decision-making is recommended. A Category A recommendation means a vaccine is recommended for everyone in an age-group or risk factor group.”

ACIP endorses individual choice on meningitis B vaccine

So there is a recommendation for older teens to get vaccinated with the Men B vaccines, it just isn’t the clear cut, get the vaccine, kind of recommendation that we are used to. The recommendation instead says that you can get the vaccine if you want to be vaccinated and protected against meningococcal B disease.

And that’s where the confusion comes from, as over 75% of doctors don’t even know what a category B recommendation really means! That’s not surprising though, as the Advisory Committee on Immunization Practices doesn’t often make category B recommendations for vaccines.

So why did the Men B vaccines only get a permissive recommendation? After all, Bexsero is routinely given to all infants in the UK at 8 weeks, 16 weeks, and 1 year as part of their routine childhood immunization schedule.

Things that factored into the decision for a permissive recommendation seemed to include that:

  • routine vaccination of all teens would prevent about 15 to 29 cases of Men B and two to five deaths each year, as there are about 50 to 60 cases and five to 10 deaths each year in children and young adults between the ages of 11 and 23 years, and giving it only to kids going to college would only prevent about nine cases and one death each year
  • there are some concerns about how effective the MenB vaccines might be, but only because vaccine effectiveness “was inferred based on an immunologic marker of protection,” as it is difficult to otherwise test how well the vaccine works because the disease has a low prevalence and there is no data yet about how long the protection will last, as they are new vaccines. Still, from 63 to 88% of people get protective levels of antibodies after getting the MenB vaccines and the protection should last for at least two to four years.
  • data on safety was limited, but there were no “no concerning patterns of serious adverse events”
  • the vaccine likely won’t reduce the nasopharyngeal colonization by MenB bacteria, so might not contribute to herd immunity

If you are still confused, you will hopefully be reassured that a combination, pentavalent MenABCW-135Y meningococcal vaccine is in the pipeline and once available, will almost certainly be recommended for all teens, replacing the need to get separate meningococcal vaccines for protection.

Making a Decision About the MenB Vaccines

So do you get your kids the Men B vaccine series?

“Pediatricians are encouraged to discuss the availability of the MenB vaccines with families.”

AAP on Recommendations for Serogroup B Meningococcal Vaccine for Persons 10 Years and Older

The one thing that is very clear is that you should make your decision after talking to your pediatrician about the risks and benefits of getting vaccinated.

Although many people think that there is no recommendation for healthy teens to get a Men B vaccine, that isn’t really true. There just isn’t a recommendation for routine vaccination of all teens.

It is true that the Men B vaccines aren’t required by most colleges, although some are starting to require them, just like they do Menactra or Menveo.

“The treating clinician should discuss the benefits, risks, and costs with patients and their families and then work with them to determine what is in their best interest.”

AAP on Recommendations for Serogroup B Meningococcal Vaccine for Persons 10 Years and Older

What are the benefits? Your child doesn’t get Men B disease, a disease that is often life-threatening.

What are the risks? In addition to extremely rare risks that you can see with any vaccine, like anaphylaxis, there are the risks that the vaccine doesn’t work, as no vaccine is 100% effective, pain from the shot, or that your child is never exposed, so didn’t actually need the shot, since Men B disease is pretty rare.

“The CDC has estimated the risk of anaphylaxis is 1.3 cases/1 million doses following administration of any vaccine. Thus, the vaccine benefit from prevention of death from MenB disease is approximately equal to the risk of anaphylaxis from MenB vaccine administration.”

H. Cody Meissner, MD on MenB vaccines: a remarkable technical accomplishment but uncertain clinical role

Although thinking about it this way, the risk of anaphylaxis vs the benefit of preventing Men B deaths seems to be equal, remember that anaphylaxis is often treatable.

What are the costs? Men B vaccines are expensive, but are covered by insurance and the Vaccines for Children Program. Still, someone is always paying for them.

What other factors come into play? Some teens are getting caught up on their HPV vaccines and are getting a booster dose of the other meningococcal vaccine at around this same time. While they can certainly all be given together, some pediatricians prioritize getting kids vaccinated and protected with Gardasil and Menactra or Menveo, and so don’t focus on the Men B vaccines.

Still, the vaccine is safe and it works, so the question really may come down to – is it necessary? Or is Men B so rare, that it is worth taking a chance and skipping this vaccine.

What to Know About the Recommendations to Get a Men B Vaccine

Talk to your pediatrician and see if your child should get the Men B vaccine series.

More on Understanding the Recommendations to Get a Men B Vaccine

Meningitis Vaccines

Meningitis is classically defined as an inflammation of the membranes that cover the brain and spinal cord.

Infections that can cause meningitis include:

  • viruses – also called aseptic meningitis, it can be caused by enteroviruses, measles, mumps, and herpes, etc.
  • bacteria – Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes, Haemophilus influenzae type b (Hib), Group B strep
  • a fungus – Cryptococcus, Histoplasma
  • parasites – uncommon
  • amebas – Naegleria fowleri

There are even non-infectious causes of meningitis, including the side-effects of medications and certain systemic illnesses.

Meningitis Vaccines

Teens and young adults need two different kinds of meningococcal vaccines to get full protection.
Teens and young adults need two different kinds of meningococcal vaccines to get full protection.

Fortunately, many of these diseases that cause meningitis are vaccine-preventable.

You don’t often think about them in this way, but all of the following vaccines are available to prevent meningitis, including:

  • Hib – the Haemophilus influenzae type b bacteria was a common cause of meningitis in the pre-vaccine era, in addition to causing epiglottitis and pneumonia
  • Prevnar – you mean it’s not just an ear infection vaccine?
  • MMR – both measles and mumps can cause meningitis
  • Menactra and Menveo – serogroup A, C, W, Y meningococcal vaccines
  • Bexsero and Trumenba – serogroup B meningococcal vaccines

But just because your child has been vaccinated doesn’t mean that you are in the clear if they are exposed to someone with meningitis. They might still need preventative antibiotics if they are exposed to someone with Hib or meningococcal meningitis.

Still, getting fully vaccinated on time is the best way to prevent many of these types of meningitis and other life-threatening diseases.

What to Know About Meningitis Vaccines

Learn which vaccines are available to provide protection against bacterial and viral meningitis.

More on Meningitis Vaccines

Cancer Vaccines Can Prevent and Treat Many Cancers

The CDC recommends HPV vaccination for 11 and 12 year olds.
The CDC recommends HPV vaccination for 11 and 12 year olds.

When you think about a cancer vaccine, what do you imagine?

Hopefully it isn’t the anti-vaccine myth that the polio vaccine causes cancer – it doesn’t.

Is it a vaccine that prevents all cancer, a so-called universal cancer vaccine? Or vaccines that target specific types of cancer?

Or do you get thoughts of a cancer vaccine that targets and kills cancer cells, treating patients once they already have cancer?

Sound too futuristic?

While a universal cancer vaccine is likely for than a few years away, many people are surprised that some of the vaccines in the current childhood and adolescent immunization schedule can actually prevent cancer.

Another vaccine is approved to treat cancer.

And that’s good news, as cancer is now the leading cause of death in the United States.

Current Cancer Vaccines

When cancer is caused by an infection, it makes sense that you can prevent the cancer by preventing the infection in the first place. That is the rationale for the current preventive cancer vaccines for the human papillomavirus (HPV) and hepatitis B:

  • Gardasil – an HPV vaccine that can be given to preteen boys and girls to protect against most genital warts and anal cancer. Gardasil also protects women against most cervical cancers.
  • Hepatitis B – the hepatitis B vaccine prevents hepatitis B infections, which when they become chronic, can develop into liver cancer.

For these vaccines to be effective, they have to be given before you are exposed to the virus. That is why it is critical for preteens to get the HPV vaccine before they become sexually active teens and young adults.

Since babies can get hepatitis B if their mother is infected and they are more likely to develop chronic hepatitis B infections, it is also important that all infants be vaccinated with the hepatitis B vaccine. Vaccination programs that instead try to target just those newborns of mothers already known to be infected with hepatitis B are much less successful than universal vaccination programs.

In addition to a preventive cancer vaccine, another type of cancer vaccine is the therapeutic or cancer treatment vaccine. This type of cancer vaccine actually helps your body fight the cancer.

So far, only one cancer treatment vaccine has been approved by the FDA.

Provenge is approved for some men with metastatic prostate cancer, increasing their survival by about 4 months. Provenge works by stimulating T lymphocytes, a part of our immune system, to kill prostate cancer cells.

Cancer Vaccines in Development

Although there are just four approved cancer vaccines in use today, there are many more in development, including:

  • DCVax(R)-L – in phase III trials to treat certain patients with glioblastoma multiforme, a type of brain tumor.
  • NeuVax – in multiple phase II trails, including one for certain patients with breast cancer to help prevent breast cancer recurrence.
  • Rindopepimut – in phase III trial to treat certain patients with glioblastoma.
  • Tecemotide – in phase III clinical trials for certain patients with non-small cell lung cancer.

Even more cancer vaccines are in phase I and phase II trials, such as WDVAX, which is in phase I clinical trials to treat certain patients with melanoma.

Although perhaps not as far along and still in early exploratory or pre-clinical research stages, there are other preventive cancer vaccines being developed too. These new vaccines would provide protection against hepatitis C (liver cancer), Epstein-Barr virus (Burkitt lymphoma, non-Hodgkin lymphoma, and Hodgkin lymphoma, etc.), Helicobacter pylori (stomach cancer), schistosomes (bladder cancer), and liver flukes (liver cancer).

What To Know About Cancer Vaccines

In addition to the hepatitis B and HPV vaccines that can prevent cancer, multiple vaccines are being developed to actually treat cancer.

For More Information On Cancer Vaccines

 

Discontinued Vaccines

tripedia
The Tripedia DTaP vaccine was discontinued in 2013.

Most people know that the RotaShield rotavirus vaccine was discontinued in 1999 because it was found to be linked to intussusception.

It took eight years for a new rotavirus vaccine to be licensed.

Lymerix, a Lyme disease vaccine was discontinued in 2002. Unfortunately, we still don’t have a new replacement Lyme disease vaccine.

Vaccines That Have Been Discontinued

More commonly, a vaccine gets discontinued with little notice, as there are other options to keep kids vaccinated and protected.

Other vaccines that are no longer made, include:

  • Menomume – an older meningococcal polysaccharide vaccine was discontinued in 2017 in the US as it was replaced with the newer meningococcal conjugate vaccines Menactra and Menveo.
  • MenHibrix – a meningococcal – Hib combination vaccine that was discontinued in the US in 2016 due to low demand
  • Cervarix – an HPV vaccine that was discontinued in the US in 2016 due to low demand
  • Comvax –  a Hib/Hepatitis B combination – discontinued in 2014
  • Tetanus toxoid – discontinued 2013
  • Tripedia – a DTaP vaccine – discontinued 2011
  • TriHIBit – a DTaP/Hib combination
  • JE-VAX – discontinued 2005
  • Attenuvax – measles vaccine
  • Mumpsvax – mumps vaccine
  • Meruvax II – rubella vaccine
  • M-R-Vax – measles and rubella combo
  • M-M-Vax – measles and mumps combo
  • Biavax II – rubella and mumps combo
  • Heptavax-B – the original hepatitis B vaccine
  • HIB-Vax – the original Hib vaccine
  • Plague vaccine
  • Poliovax
  • Dryvax – smallpox vaccine
  • Measles-Smallpox combination vaccine
  • Diptussis – a diphtheria/pertussis combination (1949-55)
  • Quadrigen – a DTP/Polio combination (1959-68)
  • Streptococcus vaccine (1952-88)
  • Serobacterin – a pertussis vaccine (1945-54)
  • Rocky mountain spotted fever vaccine (1942-78)
  • Typhus vaccine (1941-79)
  • smallpox vaccine (1917-1976)

Most of these vaccines were discontinued because they simply became obsolete.

Orig. Title: SPvac806.8a
A smallpox vaccination kit included the diluent, a vial of Dryvax smallpox vaccine, and a bifurcated needle.

The Hib-Vax and Heptavax-B vaccines, for example, both use older technology, so these vaccines were discontinued when newer Hib and hepatitis B vaccines were introduced.

And some vaccines are discontinued  or are phased out when they get an update:

  • MMR -> MMR-II (1978)
  • Prevnar 7 -> Prevnar 13 (2010)
  • Gardasil -> Gardasil 9 (2014)

Still other vaccines, like Tripedia and TriHIBit, seemed to get discontinued as a business decision. Through mergers, Sanofi Pasteur, Ltd. ended up with two DTaP vaccines. They had their own Daptacel, but also had Tripedia, a vaccine they acquired from Pasteur Merieux. They ended up discontinuing Tripedia.

Merck also stopped making Comvax not because of “any  product safety or manufacturing issues,” but rather “as part of its ongoing effort to focus company resources on opportunities that provide the greatest value for customers, patients, and public health…”

Cervarix was discontinued because of low market demand. The competing HPV vaccine, Gardasil, had the much larger market share.

Vaccine Manufacturers and Discontinued Vaccines

And of course, some vaccine manufacturers simply stopped making vaccines.

The Texas Department of Health Resources once had a license to make vaccines, including DTP, diphtheria, DT, pertussis, tetanus, Td, and typhoid vaccines since 1950. They completely exited the vaccine market in 1979.

In the 1970s and 80s, dozens of vaccines were discontinued as Miles Inc., Eli Lilly, Parke Davis, and other companies stopped making vaccines.

While that is often downplayed these days, it is important to realize that we used to have much more competition among vaccine manufacturers. For example, in the early 1970s, the DTP vaccine was made by at least 11 different companies! We now have just two that make DTaP. And in many other cases, like for Prevnar, MMR-II, polio, and the chicken pox vaccine, there is just one manufacturer.

For More Information on Discontinued Vaccines:

Updated on February 7, 2018

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