Measles: All about the measles vaccines

In my last post I discussed why we should worry about measles. Today I'll talk about the measles vaccines available to prevent the disease.

What measles vaccines are available?

There are two types of measles vaccines in the United States: MMR and MMRV.

There is no longer a separate measles vaccine available in the US.

MMR

The MMR includes protection against measles, mumps, and rubella. This vaccine can be used in infants 6 months and older and is the only vaccine approved over 13 years of age for those who need to catch up on vaccines.

The CDC recommends that MMR and varicella vaccines be given as separate injections for the first dose in children 12-47 months of age.

MMRV

In addition to measles, mumps, and rubella, the MMRV has protection against varicella (chicken pox). The MMRV can be used from 12 months through 12 years of age (until the 13th birthday).

Using the MMRV vaccine has the benefit of one fewer injection, but there are some downsides.

• It cannot be used as an early dose of measles protection prior to 12 months of age.

• The MMRV should not be used in those 13 years and older.

• The MMRV has a higher risk of fever within 42 days after vaccination compared to the MMR and Varicella vaccines being given in separate injections, even when they're given on the same date in children 12-24 months of age. There is less data on children 24-47 months of age, but it is likely that they also have this increased risk.

• The MMRV has a higher risk of febrile seizures from 5-12 days after vaccination compared to the MMR + Varicella being given in separate injections, even if given on the same date.

What is the typical age of vaccination?

One of the measles vaccines is recommended routinely at 12-15 months and then again at 4-6 years.

Either the MMR or the MMRV can be used at these standard times.

If the MMR is used, a separate varicella vaccine can be used at the same time or at a different time.

Can the 2nd dose be given early?

Yes. An early 2nd dose does count as the second dose as long as it is separated by at least 28 days from other live virus vaccines.

Early second doses do count toward the required two doses after the first birthday. There is no minimum age for the second dose, as long as both doses are after the 1st birthday and a month apart.

What does the booster dose do?

Contrary to common belief, the MMR/MMRV second dose is not a booster to increase the immunity of the first dose.

About 93% of people respond to their first measles vaccine and are protected against the measles. They are protected and wouldn't need a booster, but we can't easily tell if any individual person is immune after the first dose. It is also possible that a person is immune to some of the MMR/MMRV components but not to all of the components, so another dose is needed for protection to be more reliable.

The second vaccine helps more people convert to being immune. After the second dose, 97% of people are immune to measles.

There are some people (3%) who are not immune despite two doses, which is why we sometimes hear of a vaccinated person still getting the disease.

Herd immunity is one reason why it is important for everyone in a community who is eligible to get the vaccine to be immunized. By immunizing the community, we can protect those in the community who are not able to be vaccinated due to young age or medical condition and those who are vaccine non-responders.

High risk situations: outbreaks and travel

It is recommended to receive an MMR (or MMRV if age indicated) if there is a local outbreak and the health department recommends an early vaccine or if an infant 6-12 months of age will be traveling to an area of increased risk.

Infants and children in high risk areas can get the second dose as early as 4 weeks after the first.

Either of the measles vaccines can be used as long as they are indicated for the age of the person being vaccinated.

More about early doses

MMR can be given to infants at least 6 months of age if they are considered high risk due to travel or outbreaks.

It is not recommended for all babies to get an early vaccine at this point.

Local health departments help to advise whether or not local conditions warrant early vaccination.

International travelers should be vaccinated against measles after 6 months of age due to the higher risk of exposure during travel.

Why not give to babies under 6 months?

Under 6 months of age an infant is considered protected from his or her mother’s antibodies. These antibodies leave the baby between 6 and 12 months after birth.

The antibodies prevent the vaccine from properly working, which is why we generally start the vaccine after the first birthday, when the antibodies have likely gone away.

Does an early dose count?

Any measles vaccine dose given before the first birthday does not count toward the two doses required after 12 months of age, but might help protect against exposure if the immunity from the mother is waning.

As mentioned above, an early 2nd dose does count as long as the first dose is after the 1st birthday and the second dose is at least 28 days later.

Is it safe to give the MMR before 12 months?

It is safe for a child to get extra doses of the vaccine if needed for increased risk of exposure between 6 and 12 months.

As discussed above, it is not because of safety that it is not routinely given earlier. It may not be effective at this age if the baby still has maternal immunity.

What's the deal with live virus vaccines?

All live virus vaccines must be given either on the same date or a month apart. If they are given too close together on different dates they are less effective and the second one given does not count.

Other types of vaccines do not have this restriction, only live virus vaccines.

Examples of live virus vaccines include:

• MMR

• MMRV

• Varicella

• FluMist (only the nasal influenza vaccine, not the injectable flu vaccine)

• Oral typhoid (not on the routine vaccine schedule, but recommended for international travel)

• BCG (a vaccine against tuberculosis that is used in some countries, but not the US)

• Oral polio (a vaccine no longer used in the US, but still in use in other countries)

• Yellow fever (not on the routine vaccine schedule, but required prior to visiting some countries)

• Zoster (a vaccine for older adults, not children)

For example...

If your child has FluMist (the nasal flu vaccine) on October 1st, if he or she gets the MMR or MMRV on October 15th, the MMR/MMRV won't count.

This is becoming more difficult to track as pharmacies, work places, and other clinics offer vaccines. I can think of one instance where a parent had a child get a nasal flu vaccine a couple of weeks before the other parent brought the child in for kindergarten shots. The 2nd parent was not aware of the flu vaccine, so the live virus vaccines given at the routine well visit had to be repeated a month later. The child was not happy!

Always get documentation of the vaccines your child gets and be sure if it's not done at your child's primary care office that they get a copy! If you're transferring to a new physician, request a transfer of records in writing before your first visit to your new medical home so they have what they need to best care for your family!

Tuberculosis testing with PPD

Although this is not a live virus vaccine, tuberculosis testing can also be affected by live virus vaccines.

A false negative skin test can occur if any live vaccine is given during the month BEFORE the TB skin test is done.

If MMR vaccine is given, you should wait at least 4 weeks before doing the TB skin test unless it is given on the same date.

All vaccines, live or inactivated, can be given on the same day or at any time AFTER a TB skin test is done.

What if someone who hasn't been vaccinated is exposed to measles?

Unvaccinated people who are exposed to measles can be given post-exposure prophylaxis unless they have a vaccine contraindication.

If the MMR vaccine is given within 72 hours of initial measles exposure it may provide some protection or lead to a less severe infection.

Immunoglobulin (IG) can be given within 6 days of exposure to provide some protection.

If you think you've been exposed, contact your physician and/or the local health department.

Who shouldn't be vaccinated?

The long list of medical contraindications to vaccines that some promote is not valid. There are very few contraindications to getting the MMR vaccine. These include:

• Age less than 6 months of age

• Anyone who has had a severe allergic reaction (anaphylaxis) after a previous dose or to a vaccine component or neomycin

• Those with a known severe immunodeficiency (chemotherapy, congenital immunodeficiency, long-term immunosuppressive therapy, and some with human immunodeficiency virus [HIV] infection)

• Pregnant women

Some conditions have precautions, but not true contraindications, to the MMR vaccine. The risks and benefits of vaccination should be discussed if a person has the following:

• Moderate or severe acute illness

• Tuberculosis testing (see separate section above)

• Antibody-containing blood products within the previous 11 months

• Those who have received a live virus vaccine in the previous 4 weeks

• Seizure history

What about adults?

People born before 1957 are presumed to be immune to measles because they lived through several measles epidemics before the vaccine became available.

It is not considered necessary to check titers for these adults unless they are in a high risk group, such as healthcare providers. If their titers do not show immunity, they should be vaccinated according to current recommendations.

Adults born after 1957 should have documentation of two measles vaccines or the disease. Before 1980 it was only recommended to have one vaccine, so some adults may require another dose.

If documentation is not available, titers can be done to see if you're immune or need a vaccine. Some may choose to simply get an MMR. Talk to your doctor.

Checking titers

Titers can show if people are at risk, but are not recommended routinely. Because of the overall high level of protection (97%), the cost-benefit ratio of testing titers routinely is not in favor of testing.

Certain persons, such as healthcare providers, may have to show immunity or get additional vaccine doses.

In summary

Two doses of one of the measles vaccines available is recommended for everyone after their first birthday. A dose can be given between 6 and 12 months if there is high risk but it does not count toward those two.

The MMR vaccine can be used in any person over 6 months of age if they are needing a measles vaccine, as long as they have not received another live virus vaccine in the previous 28 days.

The MMRV vaccine can be used between 12 months and 13 years of age. There is a higher risk of fever and febrile seizures with this vaccine compared to the MMR + Varicella vaccines given separately (even on the same date).

The first measles vaccine provides protection 93% of the time. The second dose increases the protection to 97% of people.

It is very important that where you are getting your vaccines has access to previous vaccines given, especially if you are getting any live virus vaccines. Keep a copy of all your family member's vaccines available at all times.

If you are changing primary care physicians for any reason, have your records transferred prior to your first visit. This must be done in writing, but your doctor must provide these. The cost of these records will be determined by the hospital or clinic and state laws.

Always keep records of your family's vaccine records easily available. You will need these for school entry, many camps, some volunteer or work positions, and more.

Getting one of the measles vaccines is not the only type of vaccine to get. We're seeing outbreaks of measles currently, but any of the vaccine preventable diseases can make a come back if given the opportunity.