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| My beautiful bride April 23, 2005 |
Happy anniversary Holly!
In my post last week I touched on measles
vaccine effectiveness. I had already decided to write this week's post on measles
before the Centers for Disease Control and Prevention (CDC) published its
summary of measles
in the United States, 2011.
Last year there were 222 cases of measles in the U.S. Ninety
percent of those cases were either imported from other countries or linked to
imported cases. More than half of the imported measles cases came from Europe,
where there were over 30,000 cases of measles last year. The highest incidence
of measles in Europe was in infants too young to receive the measles vaccine.
Eighty six percent of measles cases in the U.S. last year were
in unvaccinated people or people whose vaccination status was unknown. Most of
the unvaccinated cases were eligible to receive measles, mumps, and rubella
vaccine (MMR), but 18 of those cases were children too young to receive MMR.
Seventy people (32% of measles cases) were hospitalized with measles in the
U.S. last year.
Measles:
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| Koplik spots CDC |
Measles is a highly contagious viral disease transmitted by
respiratory droplets. The incubation period (time from infection to the
beginning of symptoms) is 10 to 12 days. Symptoms begin with a prodrome of fever,
cough, coryza
(inflammation of the nasal sinuses), and conjunctivitis
(red eyes). These symptoms are easily confused with other upper respiratory
infections. The prodromal stage is when a person infected with the measles
virus is most contagious. Koplik spots are sores on the inside of the mouth
that occur during this period and are considered pathognomonic
for measles – meaning, if you have Koplik spots, you have the measles.
The prodromal stage lasts 2 to 4 days and ends with the
onset of a rash that begins on the head and face, spreads to the trunk, and
then the arms, legs, hands, and feet. The rash fades over 3 to 4 days in the
same order as it appeared; face, trunk, extremities.
Complications of measles:
In industrialized countries, around 1% to 6% of people with
measles with develop pneumonia,
7% to 9% will develop otitis media (ear
infection), 8% will develop diarrhea, and 1
person out of 1,000 to 2,000 will develop encephalitis as
the result of the infection.
Measles can cause severe disease and death in people with immune
deficiencies, including people with HIV/AIDS, people on
immune-suppressing drugs (e.g., cancer chemotherapy
and drugs to prevent rejection of
transplanted organs), and people with inherited
immune disorders. Measles vaccine should not be given to people with severe
immune disorders, so this is a population that is especially vulnerable to
measles.
Before the introduction of measles vaccine, there were
around 200,000 to 500,000 cases of measles every year in the U.S. As a result,
there were approximately 150,000 cases of pneumonia, 100,000 cases of otitis
media, 4,000 cases of encephalitis, and around 500 deaths caused by measles
every year in the U.S.
Globally, the number of deaths due to measles has decreased from an estimated 2.6 million in 1980 to 535,000 in 2000 and 139,000 in 2008, most of which were children in developing countries. In addition to the complication listed above, measles commonly causes diarrhea, dehydration, and blindness in children in developing countries.
Subacute
Sclerosing Panencephalitis (SSPE) is a rare but fatal complication of
measles. It begins years after the initial measles infection with mental and
behavioral changes, then progresses to myoclonic
jerking, coma, and death. Jaxon's
Cure is a website that tells the story of a boy who got the measles when he
was too young to receive the vaccine, developed SSPE when he was 5 years old,
and died two and a half years later.
Measles vaccine:
As I discussed in my post on pertussis
vaccines, antibodies are transported across the placenta from mother to
baby. The same is true of measles antibodies, which provides the newborn baby
with some protection against measles in the first months of life.
Unfortunately, these antibodies also interfere with baby's immune response to
measles vaccines, which is why measles, mumps, and rubella vaccine (MMR) is
given when babies are 12 to 15 months old - after maternal measles antibodies
have cleared from the baby's blood. In countries where the risk of measles is
high, measles vaccine is given at 9 months.
Like live
attenuated influenza vaccine (LAIV), MMR is a live
virus vaccine, so it should not be given to pregnant women because of the
theoretical risk of infecting the unborn baby with vaccine virus. Measles
infection during pregnancy can cause miscarriage and premature delivery, so
women should be up-to-date on their MMR immunization before getting pregnant.
I've reached a point where I realize that there's still a
lot to discuss and this post is already longer that I had anticipated. Besides,
it's time for me to make an anniversary dinner for my bride.
More information:
-
CDC's Travelers' Health: Measles
Update
-
Jaxon's Cure: Measles and
Subacute Sclerosing Panencephalitis (SSPE)
References:
Centers for Disease Control and Prevention. (1998). Measles,
mumps, and rubella – vaccine use and strategies for elimination of measles,
rubella, and congenital rubella syndrome and control of mumps: recommendations
of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report,
47(8),1-57. http://www.cdc.gov/mmwr/preview/mmwrhtml/00053391.htm.
Centers for Disease Control and Prevention. (2012). Measles
– United States, 2011. Morbidity and
Mortality Weekly Report, 61(15), 253-257. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6115a1.htm.
Centers for Disease Control and Prevention. (2012). Progress
in global measles control. Morbidity and
Mortality Weekly Review, 61(4), 73-78. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6104a3.htm.
European Centre for Disease Prevention and Control. (2012). Surveillance report: European monthly measles monitoring. http://ecdc.europa.eu/en/publications/publications/sur_emmo_european-monthly-measles-monitoring-february-2012.pdf.
Gershon, A. A. (2009). Measles virus (rubeola). In Mandell,
G. L., Bennett, J. E., & Dolin, R. (Eds.). Mandell, Douglas, and Bennett’s principles and practice of infectious
diseases. (7th Ed.) [Electronic version].
National Institute of Neurological Disorders and Stroke.
(2011). NINDS subacute sclerosing
panencephalitis information page. http://www.ninds.nih.gov/disorders/subacute_panencephalitis/subacute_panencephalitis.htm.
Strebel, P. M., Papania, M. J., Dayan, G. H., & Halsey,
N. A. (2008). Measles vaccine. In S. A. Plotkin, W. A. Orenstein, & P. A.
Offit (Eds.) Vaccines (5th Ed.)
[Electronic version]
