Category: Immunization Schedules

Why Are Vaccine Schedules Different in Each Country?

Anti-vaccine folks often point in differences in the immunization schedules in various countries to try and make a case that some countries do things better than others.

Is that true?

Why Are Vaccine Schedules Different in Each Country?

The ACIP and CDC set the immunization schedule in the United States, but it shouldn’t be surprising that other countries have their own systems to set their schedules.

Each country vaccinates according to their own needs, so none of their schedules are wrong, even though they are all a little different.
Each country vaccinates according to their own needs, so none of their schedules are wrong, even though they are all a little different.

And no, just because they are all a little different, that doesn’t mean that any are wrong.

That’s easy to understand once you do just a little research on how these immunization schedules are set up.

The WHO immunization schedule.
The WHO immunization schedule.

The WHO immunization schedule is set by the Strategic Advisory Group of Experts (SAGE) on Immunization.

WHO vaccine position paper development is "a complex, rigorous, multifaceted process."
WHO vaccine position paper development is “a complex, rigorous, multifaceted process.”

It’s basically a summary of WHO position papers.

The WHO recommendations help other countries develop optimal immunization schedules.

The Communicable Diseases Act in Sweden regulates the 13 factors that the Public Health Agency of Sweden must account for when proposing changes in the national vaccination programme to the Government.
The Communicable Diseases Act in Sweden regulates the 13 factors that the Public Health Agency of Sweden must account for when proposing changes in the national vaccination programme to the Government. 

Many countries also have their own National Immunization Technical Advisory Group that sets their immunization schedule.

So their immunization schedule is right for their country, even if it doesn’t match the United States schedule.

Australia’s Vaccine Schedule

In Australia, for example, the National Immunisation Program (NIP) Schedule is set by National Immunisation Committee (NIC), which reports to the Australian Health Protection Principal Committee (AHPPC) of the Australian Health Ministers Advisory Council (AHMAC) through the Communicable Diseases Network Australia (CDNA).

The Australian Technical Advisory Group on Immunisation (ATAGI) also provides technical advice on the operation of the National Immunisation Program.

Combination vaccines mean infants in Australia get fewer shots, but the same number of vaccines.
Combination vaccines mean infants in Australia get fewer shots, but the same number of vaccines.

Notice any differences between Australia’s vaccine schedule and the US schedule?

  • they give the routine second dose of MMR earlier, at 18 months
  • they don’t give a second dose of the chickenpox vaccine
  • they give the routine first dose of the meningococcal vaccine earlier, at 12 months
  • the hepatitis A and flu vaccines are only given to high risk kids

While there are some minor differences, it is fairly similar to the US immunization schedule.

“There is a legislative requirement for all vaccines provided under the NIP or the PBS to undergo a thorough and objective assessment process.”

National Immunisation Strategy for Australia

Why the earlier dose of meningococcal vaccine?

This is a good example of why immunization schedules vary between countries.

“The notification rate for meningococcal disease to the National Notifiable Diseases Surveillance System peaked at 4.3 per 100 000 in 2002 and declined to 0.4 per 100 000 in 2013.”

Meningococcal disease

Meningococcal disease incidence rates in the United States were much lower, about 0.6 per 100,000, when they started giving meningococcal vaccines in Australia (2001).

The UK Vaccine Schedule

But aren’t the immunization schedules from other countries supposed to be a lot different from the US schedule?

Let’s look at another…

The Joint Committee on Vaccination and Immunisation (JCVI) advises UK health departments on immunisation.
The Joint Committee on Vaccination and Immunisation (JCVI) advises UK health departments on immunisation.

It’s not the easiest schedule to read, but you should notice that vaccines for hepatitis A and chickenpox are missing, but younger children get extra meningococcal shots.

You may also have noticed yet another dosage schedule for the Prevnar 13 vaccine.

While the United States gives a three dose primary series and a booster, many other countries give either a three dose primary series alone or a two dose primary series with a booster.

“A large and growing body of evidence from immunogenicity studies, as well as clinical trials and observational studies of carriage, pneumonia and invasive disease, has been systematically reviewed; these data indicate that schedules of 3 or 4 doses all work well, and that the differences between these regimens are subtle, especially in a mature program in which coverage is high and indirect (herd) effects help enhance protection provided directly by a vaccine schedule.”

Whitney et al on Dosing schedules for pneumococcal conjugate vaccine: considerations for policy makers.

That doesn’t mean that they are all guessing at the dose! All of these schedules are well studied and in this case, there isn’t much difference.

There are even studies that suggest giving only one primary dose, combined with one booster dose might work, but only in areas where pneumococcal disease is already well controlled and infants would be protected by indirect herd immunity.

But that doesn’t mean that other schedules would work just as well too. For example, giving the doses later or on a slower schedule would not be better.

Why not?

Infants are most at risk for many of these diseases, especially Hib and pneumococcal disease, when they are young and delaying when infants get vaccinated simply leaves them unprotected and at risk to get sick for a longer period of time. You also want infants to be protected by the time they lose the passive protection they get from their maternal antibodies.

What about the chickenpox vaccine?

Will the UK get the chickenpox vaccine soon?

While the UK has not added the chickenpox vaccine to their schedule because their models predicted an increase in cases of shingles (which has happened anyway) with a decrease in exogenous boosting (the theory that exposure to chickenpox lowers your risk of shingles), they are now looking at this again.

“This study confirms that severe complications of varicella, including death, continue to occur in the UK and Ireland.”

Cameron et al on Severe complications of chickenpox in hospitalised children in the UK and Ireland

Mostly it has been said that the chickenpox vaccine isn’t on the schedule because they have not thought it to be cost effective.

Iceland’s Vaccine Schedule

When anti-vaccine folks talk about immunization schedules from other countries, they aren’t usually talking about the UK or Australia though.

They are talking about Iceland, the country that they believe gives far fewer vaccines than the United States.

You thought they gave even fewer vaccines in Iceland, didn't you?
You thought they gave even fewer vaccines in Iceland, didn’t you?

Vaccines for flu, chickenpox, hepatitis A, and hepatitis B and also available for those who are considered high risk.

Extra vaccines are available for high risk kids.

Want to follow Iceland’s immunization schedule?

Then you should move to Iceland.

Hopefully you are starting to see that immunization schedules are different in each country because each country has different rates of disease, different populations, and different healthcare systems.

Iceland is a small country (338,349 people), with high vaccination rates, and universal health care. Compare that to the United States, with 327,200,000 people, clusters of unvaccinated people, and lots of people without health care.

It should be easy to see that what works in one country might not work in the other…

Vaccine Schedule Comparison by Country

What about other countries?

Austria’s immunization schedule for 2019 includes all of the same vaccines as the US schedule, plus the vaccine for Japanese encephalitis (if high risk).
Austria’s immunization schedule for 2019 includes all of the same vaccines as the US schedule, plus the vaccine for Japanese encephalitis (if high risk).

On the immunization schedule in Austria, the columns in red are for vaccines that are recommended and free. The blue columns are also recommended, but they aren’t free.

The chickenpox vaccine was just added to Japan's routine vaccine schedule, but they still don't give the combined MMR vaccine. They do still have autistic kids, so does that finally prove that the MMR vaccine is not associated with autism?
The chickenpox vaccine was just added to Japan’s routine vaccine schedule, but they still don’t give the combined MMR vaccine. They do still have autistic kids, so does that finally prove that the MMR vaccine is not associated with autism?

Japan has two separate schedules – the routine schedule for everyone (in dark blue above) and the voluntary schedule, with extra vaccines. Note that the primary series of infant vaccines are given at 2, 3, and 4 months.

The latest vaccine schedule in Germany.
The latest vaccine schedule in Germany.

Germany also gives their primary series of infant vaccines at 2, 3, and 4 months.

In contrast to the 16 diseases that kids in the US are vaccinated against, Sweden uses vaccines for just 9.
In contrast to the 16 diseases that kids in the US are vaccinated against, Sweden uses vaccines for just 9.

Sweden is the other country that anti-vaccine folks like to talk about a lot. Mostly because they think that Sweden recently banned mandatory vaccination. They didn’t.

And note that kids in Sweden can get vaccinated at school!

The Norwegian immunization program makes heavy use of combination vaccines.
The Norwegian immunization program makes heavy use of combination vaccines.

Norway is studying adding chickenpox and Shingles vaccines to their schedule.

Switzerland now offers a few optional vaccines for folks who want them, including the meningococcal vaccine, HPV vaccines for boys, and the shingles vaccine for seniors.
Switzerland now offers a few optional vaccines for folks who want them, including the meningococcal vaccine, HPV vaccines for boys, and the shingles vaccine for seniors.

Although they only use a two dose primary series, Switzerland gives many of the same vaccines as the United States.

The 2018 vaccination schedule in the Netherlands. New additions in 2020 will be the rotavirus vaccine or high risk infants, Tdap in pregnancy, and MenACWY for teens.
The 2018 vaccination schedule in the Netherlands. New additions in 2020 will be the rotavirus vaccine or high risk infants, Tdap in pregnancy, and MenACWY for teens.

Are you surprised to see that infants in Holland get more vaccines before they turn 12 month old than infants in the United States and an extra set by four months?

While most vaccines are free, you can pay extra to get vaccines that are already on the United States schedule in most other countries.
While most vaccines are free, you can pay extra to get vaccines that are already on the United States schedule in most other countries.

Even if they aren’t routine in other countries, all of the same vaccines that are offered in the United States, including vaccines to protect kids against rotavirus, chickenpox, and hepatitis A, are available in most other countries.

Vaccination schedule for children and adolescents in Israel.
Vaccination schedule for children and adolescents in Israel.

The latest immunization schedule in Israel includes hepatitis B, DTaP, polio, pneumococcal, rotavirus, MMR, chickenpox, HPV, and flu vaccines.

The 2019 Immunization Schedule for South Korea includes almost all of the US vaccines, plus BCG and Japanese encephalitis vaccines.
The 2019 Immunization Schedule for South Korea includes almost all of the US vaccines, plus BCG and Japanese encephalitis vaccines.

What’s missing in South Korea’s immunization schedule? Meningococcal vaccines. But they do have some that we don’t give in the United States.

What’s missing in Denmark?

Vaccines for rotavirus, chickenpox, hepatitis A or B, and meningococcal disease are not offered for free, but are still available in Denmark.

Folks who don’t vaccinate their kids!

Denmark has very high immunization rates – over 97% for infants and toddlers!

In addition to free vaccines, the Danish vaccine program offers these vaccines that folks can ask for and pay for themselves. Some people in high risk groups can get them free.

What don’t these different immunization schedules influence?

Prevalence rates of autism, SIDS, and other things that scare parents away from vaccinating and protecting their kids.

The One Wrong Way to Give Vaccines

Since the immunization schedules from all of these countries are just a little bit different, does that support the idea that an individualized approach to vaccinating kids is a good idea?

There is no science and nothing that says altering any vaccine schedule is a safer or more effective way to do things.
There is no science and nothing that says altering any vaccine schedule is a safer or more effective way to do things.

Of course not!

"Later and slower" is not part of any immunization plan.
“Later and slower” is not part of any immunization plan.

In many countries, even if they are missing protection against a few diseases that we routinely vaccinate against in the United States, many get their vaccines earlier! And all start by three months and don’t split up the schedule to just give one or two vaccines at a time.

Everyone knows that later and slower just leaves kids unprotected for longer periods of time. More risks. No extra benefits.

More on Vaccine Schedules Around the World

How is the Immunization Schedule Developed?

For some reason, there still seems to be a lot of confusion out there about just how the immunization schedule is developed.

Jay Gordon wonders about the research used to set the current immunization schedule...
ICYMI – Jay Gordon was Jenny McCarthy‘s pediatrician.

Who decides which vaccines we give and get?

How do they make that decision?

History of Immunization Schedule Development

While the current immunization schedule is developed by the CDC based on recommendations of the Advisory Committee on Immunization Practices (ACIP), that’s not how it was always done.

It has just been since 1995 that we have had this single, simple vaccine schedule and format.

The first unified immunization schedule was developed in 1995.
The first unified immunization schedule was developed in 1995.

Before that, we had separate vaccine schedules from the:

Even earlier, we had recommendations and schedules from

  • WHO Expanded Programme on Immunization (EPI)
  • AAP’s Special Committee on Prophylactic Procedures Against Communicable Diseases – from its start in the early 1930s, it evolved into today’s Committee on Control of Infectious Diseases
  • American Public Health Association Subcommittee on Communicable Disease Control

Differences in those schedules, which could lead to confusion, lead experts to create a simpler, unified schedule.

Well, at least in the United States. Of course, other countries still set their own schedules…

The Science Behind Setting the Immunization Schedule

Now that you know who sets the immunization, you are probably wondering how they set the immunization schedule.

To truly understand how the immunization schedule gets set up, it is best to go to an ACIP meeting when they make those decisions.

Can’t make it to Atlanta for one of the ACIP meetings?

You can watch them online!

Thoughtful discussions on setting the immunization schedule at ACIP.
Thoughtful discussions on setting the immunization schedule at ACIP.

Past ACIP meetings, agendas, minutes, slides, and videos, are archived online too.

Reading the minutes from the third meeting of the Advisory Committee on Immunization Practices on November 19-20, 1964 shows how they work, looking at data to make decisions about our vaccines and set the immunization schedule.
Reading the minutes from the third meeting of the Advisory Committee on Immunization Practices on November 19-20, 1964 shows how they work, looking at data to make decisions about our vaccines and set the immunization schedule.

Review them and you will get a very good idea of how the immunization schedule gets set up.

The first flu vaccine was developed in 1945.

ACIP basically told folks to go back to the drawing board and make a better flu vaccine at this 1966 meeting.
ACIP basically told folks to go back to the drawing board and make a better flu vaccine at this 1966 meeting.

Did you ever wonder why it took so long to get it on the immunization schedule?

Why was the primary series of polio vaccines made up of three doses?

At the Advisory Committee on Immunization Practices meeting on May 24-26, 1967 they discussed polio vaccine scheduling.
At the Advisory Committee on Immunization Practices meeting on May 24-26, 1967 they discussed polio vaccine scheduling.

Hopefully you are starting to understand how this works…

And no, all of this work doesn’t get done over a couple of days a few times a year. ACIP members belong to workgroups which focus on specific vaccines and they gather, analyze, and prepare information and research about those vaccines throughout the year.

It is at the ACIP meetings where the workgroup findings are presented.

“Development of vaccine schedules is based on a large body of basic sciences and epidemiologic research. There is constant review of evidence, adverse events, and epidemiology by a panel of experts.”

Shetty et al on Rationale for the Immunization Schedule: Why Is It the Way It Is?

And yes, among that body of research are studies of vaccines tested together, vaccines tested with placebos, vaccines tested vs unvaccinated kids, vaccines tested for long periods of time, and studies looking at risk factors to make sure vaccines don’t cause long-term health problems.

It’s a very thorough process!

And that’s why the great majority of folks understand that following the immunization schedule is the best way to keep their kids protected from vaccine-preventable diseases.

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

What’s not safe? What hasn’t been well studied?

Following a non-standard, parent-selected, delayed protection vaccine schedule.

Thinking that an individualized approach is better doesn't trump the 55 years of ACIP meetings that went into setting the current immunization schedule...
Thinking that an individualized approach is better doesn’t trump the 55 years of ACIP meetings that went into setting the current immunization schedule…

Studies have actually shown that delaying or skipping vaccines offers no benefits and actually puts kids at extra risk.

It puts the rest of us at risk too.

More on Setting the Immunization Schedule

Vaccine Schedules from the 1940s to 2019

To scare parents away from vaccinating and protecting their kids, anti-vaccine folks continue to push the idea the kids get too many vaccines at too early an age.

They don’t.

When did we have a vaccine schedule when we gave just two vaccines?
When did we have a vaccine schedule when we gave just two vaccines?

They try to reinforce the idea by comparing things to the “good ol’ days,” when they think kids only got one dose of one or two vaccines.

Did they?

Vaccine Schedules from the 1940s to 2019

Let’s take a look at how the vaccine schedule has evolved over time to see how many vaccines kids used to get. Looking at the old vaccine schedules can also help you understand how we got to our current schedule.

Although not a formal schedule, the first vaccine recommendations were published in the AAP’s Special Committee on Prophylactic Procedures Against Communicable Diseases 1938 pamphlet, Routine measures for the prophylaxis of communicable diseases.

It included vaccines against diphtheria, pertussis, rabies, tetanus, tuberculosis, typhoid fever, and smallpox.

A schedule of immunizations from a 1948 AAP Round Table Discussion on the Practical and Immunological Aspects of Pediatric Immunizations
A schedule of immunizations from a 1948 AAP Round Table Discussion on the Practical and Immunological Aspects of Pediatric Immunizations

That’s the schedule from 1948!

Surprised?

Many of you were led to believe that kids only got 2 vaccines back in the day. Instead, they got more vaccines and multiple doses of those vaccines.

Multiple doses with formaldehyde inactivated vaccines which contained aluminum. And thimerosal. And far more antigens than kids are exposed to today, even though they now get many more vaccines.

My uncle got polio around the time this vaccine schedule was released in 1951, but before the first polio vaccines were being routinely used.
My uncle got polio around the time this vaccine schedule was released in 1951, but before the first polio vaccines were being routinely used.

By the early 1950s, the DPT vaccine became routine. Other vaccines were also available for special situations, including rabies, typhoid, parathyphoid, and the BCG vaccine.

And of course, we got the polio shot in 1955!

Kids got multiple doses of DPT, DT, polio, and smallpox vaccines in 1960.
Kids got multiple doses of DPT, DT, polio, and smallpox vaccines in 1960.

Although few people remember, the original polio vaccines were monovalent and only included one polio strain in each shot. So you had to get multiple shots to get protected from all three strains!

The polio shot, was used until 1962, when we switched to the oral polio vaccine. Trivalent OPV wasn’t licensed until 1963 though. Before that, kids got multiple doses of monovalent OPV, types 1, 2, and 3.

The ACIP committee came up with four different dosage schedules for measles vaccines in 1964.
The ACIP committee came up with four different dosage schedules for measles vaccines in 1964.

And for a few years, we had both inactivated and live measles vaccines…

The recommended immunization schedule by the AAP in the 1966 Red Book. The first measles vaccine was approved in 1963.

Next came the individual mumps (1967) and rubella (1969) vaccines and the combination MMR vaccine (1971).

And the end of routine vaccination with the smallpox vaccine (1972).

Eleven doses of four vaccines protected kids against seven vaccine-preventable diseases in 1983.
Eleven doses of four vaccines protected kids against seven vaccine-preventable diseases in 1983.

The Hib vaccine was added in 1985.

Twelve doses of five vaccines protected kids against eight vaccine-preventable diseases in 1989.
Twelve doses of five vaccines protected kids against eight vaccine-preventable diseases in 1989.

Next came the hepatitis B vaccine and expanded age ranges for the Hib vaccine.

Seventeen doses of five vaccines protected kids against eight vaccine-preventable diseases in 1989 (plus the later Td booster).
Nineteen doses of six vaccines protected kids against nine vaccine-preventable diseases in 1995.

What’s still missing?

Vaccines and protection against rotavirus, hepatitis A, chicken pox, flu, pneumococcal bacteria, meningococcal bacteria, and HPV. And no, they weren’t all added right after the National Childhood Vaccine Injury Act of 1986, another anti-vaccine myth!

Those vaccines were added to the schedule much later:

  • Varivax – a chickenpox vaccine (1995)
  • the polio shot – we began to switch back in 1996
  • VAQTA – the first hepatitis A vaccine was approved for high risk kids in 1996, but wasn’t actually added to the routine vaccine schedule until 2006
This is the immunization we used when I finished residency...
This is the immunization we used when I finished residency…

RotaShield, the first rotavirus vaccine was approved in 1998 but was quickly withdrawn in 1999 because of an increased risk of intussusception

What’s next?

  • Prevnar, with protection against pneumococcal bacteria (2000)
  • FluMist – the nasal spray flu vaccine (2004)
  • new flu shots recommendations for all healthy infants (2004)

Is the vaccine schedule starting to look familiar?

RotaTeq and Gardasil were added to the vaccine schedule the next year, in 2007.
RotaTeq and Gardasil were added to the vaccine schedule the next year, in 2007.

Since then, Prevnar was updated to include protection against 13 strains of pneumococcal bacteria. And we got a new vaccine that covers the B strain of meningococcal disease, but otherwise there haven’t been any major changes to the vaccine schedule in a while.

The 2019 vaccine schedule.
The 2019 vaccine schedule.

Do you see 72 vaccines on the schedule?

Kids today routinely get 13 vaccines that protect them 16 vaccine-preventable diseases.

Do you see 72 doses of vaccines on the schedule?

Guess what? These folks are deliberately misleading you.
Guess what? These folks are deliberately misleading you.

Kids don’t get 72 doses of vaccines today.

That’s an inflated number that’s used to scare parents. That it is a propaganda technique should be obvious, as the folks who use it don’t use the same anti-vaccine math to inflate the number of doses from the historical schedules.

More on Vaccine Schedules from the 1940s to 2019

Do You Need Another Dose of the MMR Vaccine?

The measles outbreaks have a lot of people concerned about measles.

And that means measles and vaccines are getting a lot of extra attention.

Unfortunately, getting extra attention doesn’t always translate into getting great advice, especially when it is leading a lot of folks into thinking they need to rush out and get another dose of MMR or to check their titers to make sure they are protected.

Do You Need Another Dose of the MMR Vaccine?

So are you protected against measles?

Have you had two doses of MMR? (Remember, kids typically get their first dose at age 12-15 months and a second dose when they are 4-6 years old, with early doses in high-risk situations.)

If you have documentation of two doses of MMR (or a measles containing vaccine), then you can confidently say that you are protected. No, it’s not 100% protection, but it’s close.

“Documented age-appropriate vaccination supersedes the results of subsequent serologic testing. If a person who has 2 documented doses of measles- or mumps-containing vaccines is tested serologically and is determined to have negative or equivocal measles or mumps titer results, it is not recommended that the person receive an additional dose of MMR vaccine. Such persons should be considered to have presumptive evidence of immunity.”

Prevention of Measles, Rubella, Congenital Rubella Syndrome, and Mumps, 2013: Summary Recommendations of the Advisory Committee on Immunization Practices (ACIP)

If you haven’t had two doses of MMR, then know that two doses are your best protection against measles.

Have you heard that people born before 1989 may need another dose?

What is the significance of the year 1989?

The recommendation to give a routine second dose of MMR started in 1990, so folks born much before then likely only had one dose, unless they were considered high risk and had the second dose before traveling out of the country, starting a healthcare job, or going to college, etc.

Instead of 1989, the typical cutoff year for protection is around 1986, since those kids would have been turning four years old in 1990, so would have gotten their second dose of MMR on schedule. If you were born before 1986, you would have started kindergarten before the recommendation to get a second dose.

The other years that are important are 1963 to 1967, as that’s when the very first measles vaccine was used, a vaccine that was later found to not be very effective. If that is the only time you were vaccinated, then you should be vaccinated again.

What about 1957?

In general, if you were born before 1957, we assume that you had measles because most people had measles back then. Maybe you didn’t though, so in a high-risk situation, like traveling out of the country or in the middle of an outbreak, this could be a good situation to check your measles titer to confirm that you are immune. If you aren’t, then get two doses of MMR.

How many doses of MMR have you had?
How many doses of MMR have you had?

So here are your scenarios:

  • Were you born before 1957? Then you probably had measles, but can check your titers to make sure you are immune, especially if you will be in a high-risk situation, like near an outbreak or traveling.
  • Did you get a dose of measles vaccine between 1963 and 1967? If this was your only dose, then you should get a dose of MMR now.
  • Did you get a measles vaccine between 1968 and 1971, before the MMR became available? That counts as a dose of measles containing vaccine. If that is your only dose, then you might get another dose of MMR, if you will be in a high-risk situation, like near an outbreak or traveling.
  • Have you only had only one dose of MMR or other measles containing vaccine, which is more likely if you were born well before 1990? Then get another dose of MMR if you will be in a high-risk situation, like near an outbreak or traveling.
  • Have you had two doses of MMR vaccine or or other measles containing vaccine (and have your immunization records to prove it)? Then you should be protected. You don’t need to check your titers and you don’t need a third dose of MMR.

What if you aren’t sure? Then get at least one more dose of MMR.

If you don’t think that you were ever vaccinated against measles, then you might get two doses of MMR.

If you aren’t sure, but think that you already were vaccinated, then this would be a good situation to check your titer. Be prepared to get your MMR vaccines again if you are negative though.

Do all adults need two doses of MMR?

Surprisingly no, although that is considered the best protection against measles, there was never a general catch up program for older folks with the recommendation to get a second dose in 1990. So if you have had one dose of MMR and aren’t at any extra risk to get measles – no travel, no nearby outbreaks, and not a health professional, etc., then one dose might be enough… for now.

More on MMR Vaccines