IAC Express 2011 |
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Issue number 932: May 25, 2011 |
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Contents
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- CDC
reports 118 measles cases across the U.S. in 2011,
the highest number of cases reported for any January-May
period since 1996
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| Abbreviations |
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AAFP, American Academy of Family Physicians; AAP,
American Academy of Pediatrics; ACIP, Advisory Committee on Immunization
Practices; AMA, American Medical Association; CDC, Centers for Disease
Control and Prevention; FDA, Food and Drug Administration; IAC, Immunization
Action Coalition; MMWR, Morbidity and Mortality Weekly Report; NCIRD,
National Center for Immunization and Respiratory Diseases; NIVS, National
Influenza Vaccine Summit; VIS, Vaccine Information Statement; VPD,
vaccine-preventable disease; WHO, World Health Organization. |
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Issue 932: May 25, 2011 |
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1. |
CDC reports 118 measles cases
across the U.S. in 2011,
the highest number of cases reported for any January-May
period since 1996
On May 24, CDC published "Measles--United States,
January-May 20, 2011" as an MMWR Early Release. Portions of the
article are reprinted below.
Measles is a highly contagious, acute viral illness that can
lead to serious complications and death. Endemic or
sustained measles transmission has not occurred in the
United States since the late 1990s, despite continued
importations. During 2001-2008, a median of 56 (range: 37-140) measles cases were reported to CDC annually; during the
first 19 weeks of 2011, 118 cases of measles were reported,
the highest number reported for this period since 1996. Of
the 118 cases, 105 (89%) were associated with importation
from other countries, including 46 importations (34 among
U.S. residents traveling abroad and 12 among foreign
visitors). Among those 46 cases, 40 (87%) were importations
from the World Health Organization (WHO) European and South-East Asia regions. Of the 118, 105 (89%) patients were
unvaccinated. Forty-seven (40%) patients were hospitalized
and nine had pneumonia. The increased number of measles
importations into the United States this year underscores
the importance of vaccination to prevent measles and its
complications. . . .
During January 1-May 20, 2011, a total of 118 cases were
reported from 23 states and New York City, the highest
reported number for the same period since 1996. Patients
ranged in age from 3 months to 68 years; 18 (15%) were aged
<12 months, 24 (20%) were aged 1-4 years, 23 (19%) were aged
5-19 years, and 53 (45%) were aged >=20 years. Measles was
laboratory-confirmed in 105 (89%) cases, and measles virus
RNA was detected in 52 (44%) cases. Among the 118 cases, 105
(89%) were import-associated, of which 46 (44%) were
importations from at least 15 countries, 49 (47%) were
import-linked, and 10 (10%) were imported virus cases. The
source of 13 cases not import-associated could not be
determined. Among the 46 imported cases, most were among
persons who acquired the disease in the WHO European Region
(20) or South-East Asia Region (20), and 34 (74%) occurred
in U.S. residents traveling abroad.
Of the 118 cases, 47 (40%) resulted in hospitalization. Nine
patients had pneumonia, but none had encephalitis and none
died. All but one hospitalized patient were unvaccinated.
The vaccinated patient reported having received 1 dose of
measles-containing vaccine and was hospitalized for
observation only. Hospitalization rates were highest among
infants and children aged <5 years (52%), but rates also
were high among children and adults aged >=5 years (33%).
Unvaccinated persons accounted for 105 (89%) of the 118
cases. Among the 45 U.S. residents aged 12 months-19 years
who acquired measles, 39 (87%) were unvaccinated, including
24 whose parents claimed a religious or personal exemption
and eight who missed opportunities for vaccination. Among
the 42 U.S. residents aged >=20 years who acquired measles,
35 (83%) were unvaccinated, including six who declined
vaccination because of philosophical objections to
vaccination. Of the 33 U.S. residents who were vaccine-eligible and had traveled abroad, 30 were unvaccinated and
one had received only 1 of the 2 recommended doses.
Nine outbreaks accounted for 58 (49%) of the 118 cases. The
median outbreak size was four cases (range: 3-21). In six
outbreaks, the index case acquired measles abroad; the
source of the other three outbreaks could not be determined.
Transmission occurred in households, child care centers,
shelters, schools, emergency departments, and at a large
community event. The largest outbreak occurred among 21
persons in a Minnesota population in which many children
were unvaccinated because of parental concerns about the
safety of measles, mumps, and rubella (MMR) vaccine. That
outbreak resulted in exposure to many persons and infection
of at least seven infants too young to receive MMR vaccine.
Editorial Note . . . .
The unusually large number of importations into the United
States in the first 19 weeks of 2011 is related to recent
increases in measles in countries visited by U.S. travelers.
The most frequent sources of importation in 2011 were
countries in the WHO European Region, which has accounted
for the majority of measles importations in the United
States since 2005, and the South-East Asia Region. This
year, 33 countries in the WHO European Region have reported
an increase in measles. France, the source of most of the
importations from the European Region, is experiencing a
large outbreak, with approximately 10,000 cases reported
during the first 4 months of 2011, including 12 cases of
encephalitis, a complication that often results in permanent
neurologic sequelae, 360 cases of severe measles pneumonia,
and six measles-related deaths.
Measles can be severe and is highly infectious; following
exposure, up to 90% of susceptible persons develop measles.
Measles can lead to life-threatening complications. During
1989-1991, a resurgence of measles in the United States
resulted in >100 deaths among >55,000 cases reported,
reminding U.S. residents of the potential severity of
measles, even in the era of modern medical care. In the
years that followed, the United States witnessed the return
of subacute sclerosing panencephalitis among U.S. children,
a rare, fatal neurologic complication of measles that had
all but disappeared after measles vaccine was introduced in
the 1960s.
Children and adults who remain unvaccinated and develop
measles also put others in their community at risk. For
infants too young for routine vaccination (age <12 months)
and persons with medical conditions that contraindicate
measles immunization, the risk for measles complications is
particularly high. These persons depend on high MMR
vaccination coverage among those around them to protect them
from exposure. In the United States this year, infants aged
<12 months accounted for 15% of cases and 15% of
hospitalizations. In Europe in recent years, measles has
been fatal for several children and adolescents, including
some who could not be vaccinated because they were immune
compromised.
Rapid control efforts by state and local public health
agencies, which are both time intensive and costly, have
been a key factor in limiting the size of outbreaks and
preventing the spread of measles into communities with
increased numbers of unvaccinated persons. Nonetheless,
maintenance of high 2-dose MMR vaccination coverage is the
most critical factor for sustaining elimination. For
measles, even a small decrease in coverage can increase the
risk for large outbreaks and endemic transmission, as
occurred in the United Kingdom in the past decade.
Because of ongoing importations of measles to the United
States, healthcare providers should suspect measles in
persons with a febrile rash illness and clinically
compatible symptoms (e.g., cough, coryza, and/or
conjunctivitis) who have recently traveled abroad or have
had contact with travelers. Providers should isolate and
report suspected measles cases immediately to their local
health department and obtain specimens for measles testing,
including viral specimens for confirmation and genotyping.
MMR vaccine is safe and highly effective in preventing
measles and its complications. MMR vaccine is recommended
routinely for all children at age 12-15 months, with a
second dose at age 4-6 years. For adults with no evidence of
immunity to measles, 1 dose of MMR vaccine is recommended
unless the adult is in a high-risk group (i.e., healthcare
personnel, international travelers, or students at post-high
school educational institutions), in which case, 2 doses of
MMR vaccine are recommended. Measles is endemic in many
countries, and exposures might occur in airports and in
countries of travel. All travelers aged >=6 months are
eligible to receive MMR vaccine and should be vaccinated
before travel. Maintaining high immunization rates with MMR
vaccine is the cornerstone of outbreak prevention.
To access a complete ready-to-print (PDF) version of this
MMWR Early Release, go to:
http://www.cdc.gov/mmwr/pdf/wk/mm60e0524.pdf
To access a complete web-text (HTML) version of this MMWR
Early Release, go to:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm60e0524a1.htm
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