The measles in the 60s and early 70s caused so much death and destruction
in early 1970s that measles vaccines became mandatory in Canada- and we had
health units do each and every school- teachers and moms were having babies
with severe disabilities and way 2 often death..... and in those days.... u
stayed home until the whole house was cleared... BECAUSE WE LEARNED THE HARD
WAY IN CANADA FROM POLIO AND TB..... (ask Newfoundland)...... there is no
justification or any right that trumps the wellness of Canadians period... just
ask Ebola.... quarantine the families.... like we used 2.... it's not like
Canada has the biggest population in the world... even with internet global
'WE' crap..... we still live day 2 day as Canadians on actual Canada life....
this ain't no video game folks.... and ask a child... or worse, if possible, a
teen or a pregnant mom.... about the vicious cruelty of measles.... just ask
them.... THERE'S THE REAL STORY.... ASK THE SURVIVORS... AND ASK THOSE WHO HAVE
BURIED THEIR DEAD BECAUSE OF INHUMANITY AND SPOILT ATTITUDES.... imho...
Michael de Adder... hugs Canadian son... u gots it again... as usual. O:-)
SIDEBAR:
In 1963 the measles vaccine was developed, and by the late 1960s,
vaccines were also available to protect against mumps (1967) and rubella
(1969).
---------------
In a retrospective study of ten epidemics of measles in virgin-soil populations in Greenland, 368 women were found to be pregnant at the time of their infection with measles. Information on the course of the pregnancies was obtained in 327 of these women and a clinical examination was made of 252 of their children. The risk of fetal death among women infected in the first trimester was found to be high. About half of 20 women infected during their first two months of pregnancy and a fifth of 31 women infected in the third month had abortions. 9% of 64 women infected in the first trimester and going to term had stillbirths. 28 women infected in the first two months of pregnancy had live children, but four of these had congenital malformations, three of extreme rarity and severity, leading to death. The rate of perinatal mortality and prematurity was equal among infants exposed to measles in the first, second and third trimester of fetal life.
PMID:
559402
[PubMed - indexed for MEDLINE]
The rate of perinata
http://www.ncbi.nlm.nih.gov/pubmed/559402
-----------------
Measles as a cause of fetal defects. A retrospective study of tem measles epidemics in Greenland.
Abstract
-----------------
------------
Scandinavian model for eliminating measles, mumps, and rubella.
This article has been cited by other articles in PMC.
Full text
Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (809K), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1443676/
--------------
mother had german measles 1960s
-------------------
-----------------
--------------
--------------------------------
I grew up in the '60s and caught absolutely nothing...
I was the beneficiary of a rigorous childhood vaccination
program that was administered to me and my schoolmates in elementary school.
I remember the shots by air guns and needles and the oral doses that we all lined up in the school auditorium to recieve.
Although some of my school aged pals would come down with occasional cases of mumps or the measles, others and myself did not.
I've never had any childhood disease. I never knew of a case of a bad reaction from any vaccination either. I was quite willing to take that moment of pain from an airgun or a needle than to have to endure the illness from a disease.
Quite frankly until recently, until the advent of the anti-vax movement, I presumed that my experience at a young age would be consistent with kids today, recieving vaccinations of their own and also protecting them from the same diseases that I completely avoided.
I was wrong, obviously. I'm also incredulous that parents, who have for the most part also benefited from the same childhood vaccination program that protected them, would skip out on those protections for their own kids.
What the hell are these people thinking?
Vaccinations not only protect our kids and ourselves, they protect the community as a whole.
I still have the vaccination scar on my left arm and I wear it as a badge of honor. During my lifetime, I've seen the same mark on the arms of others who were around my age. I considered it mark of protection.
Before me, a lot of other kids didn't have the same form of protection as I, and sickness was quite common. But since the program we've gone a long time without the outbreaks of childhood diseases, that I thought could've been easily avoided.
But we're regressing in that arena, are we not?
Anti-vaxxers are a selfish, illinformed and dangerous lot who are not only putting themselves and their own children in jeopardy but the rest of us as well. Anti-vax philosophy has far ranging consequences beyond the people who've adopted it.
It's practically insane.
I remember the shots by air guns and needles and the oral doses that we all lined up in the school auditorium to recieve.
Although some of my school aged pals would come down with occasional cases of mumps or the measles, others and myself did not.
I've never had any childhood disease. I never knew of a case of a bad reaction from any vaccination either. I was quite willing to take that moment of pain from an airgun or a needle than to have to endure the illness from a disease.
Quite frankly until recently, until the advent of the anti-vax movement, I presumed that my experience at a young age would be consistent with kids today, recieving vaccinations of their own and also protecting them from the same diseases that I completely avoided.
I was wrong, obviously. I'm also incredulous that parents, who have for the most part also benefited from the same childhood vaccination program that protected them, would skip out on those protections for their own kids.
What the hell are these people thinking?
Vaccinations not only protect our kids and ourselves, they protect the community as a whole.
I still have the vaccination scar on my left arm and I wear it as a badge of honor. During my lifetime, I've seen the same mark on the arms of others who were around my age. I considered it mark of protection.
Before me, a lot of other kids didn't have the same form of protection as I, and sickness was quite common. But since the program we've gone a long time without the outbreaks of childhood diseases, that I thought could've been easily avoided.
But we're regressing in that arena, are we not?
Anti-vaxxers are a selfish, illinformed and dangerous lot who are not only putting themselves and their own children in jeopardy but the rest of us as well. Anti-vax philosophy has far ranging consequences beyond the people who've adopted it.
It's practically insane.
--------------
Growing Up Deaf - Rubella
Could It Happen Again?
Updated December
29, 2014.
Rubella (also known as german measles) is a
virus infection that causes a brief red rash, and a low fever. If it happens
early in a pregnancy, the baby can be born deaf. (Babies can also be born
blind, with heart problems, mental retardation, or cerebral palsy, among other
things.)
Rubella's Effect on Me
I am deaf because of maternal rubella. In
1963-1965, there was an epidemic
of rubella in the United States.
(Before a vaccine was developed, the United States had cyclical epidemics of
rubella.) That 1963-1965 epidemic produced thousands of deaf babies like
myself.
Rubella may have done other things to me too. It
made my hands small, and it could be why I am under five feet tall. Rubella is
a very damaging virus. In the mid 1990s I read a rubella fact sheet that
stated the rubella virus can cause stillbirth. I realized I was fortunate to be
born alive, and merely deaf.
Like many rubella babies born decades ago, my
deafness was not identified until I was a year and a half old. I was part of a
"Rubella Project" at New York University. I went to their offices and
took tests that measured intelligence and other skills. "Rubella
babies" have been the subject of several studies, and are still being
followed today as they age.
Rubella's Educational Impact
The Rubella Bulge of the '60s
filled schools for the deaf, and later overcrowded colleges for the deaf. This
educational impact has been well-documented in articles and studies. (In
addition, when I was a NTID/RIT student, I wrote an article on the rubella
bulge for the RIT Reporter
magazine that was reprinted in
the Summer 1982 NTID Focus magazine).
Rubella's Disappearing Act
Rubella has been eliminated in
the United States, according to the Washington Post (March 21, 2005).
The Post reported "Fewer than 10 people a year in this country now
contract the infection known popularly as German measles. Since 2002, all cases
have been traceable to foreigners who carried the virus in from abroad."
However, it is a different story in
still-developing countries. In those countries, rubella is still a problem due
to lack of vaccination (for example, in India, as reported by Hearing Health
magazine, Summer 2004). That same Washington Post article also reported
that according to the World Health Organization, around 100,000 babies are born
annually worldwide with congential rubella syndrome.
Two organizations currently tracking rubella in
foreign countries and actively involved in efforts to eradicate it are the Pan
American Health Organization (www.paho.org) that focuses on North and South
America, and the World Health Organization (www.who.int). The WHO has a page on
rubella with world maps showing which countries currently vaccinate routinely
for rubella. The map I viewed, for August 2006, showed the primary gaps to be
Africa and East Asia.
Rubella in Blog Posts
Rubella has been a topic of
previous blog postings:
Rubella Information Online
Several sources of general
information on rubella are available online. Here are two:
- The Helen Keller National Center for Deaf-Blind Youths and Adults(www.hknc.org) has a page on rubella. In March 2005, the Center sponsored a rubella conference.
- The ADAM Healthcare Center also has a detailed page on rubella, including graphical illustrations of rubella and its effects.
Rubella and Deafness Information for Researchers
Gallaudet University Library
The Gallaudet University library at Gallaudet
University in Washington, DC, has some old gems about rubella and deafness
found via a catalog.wrlc.org search (the search turned up more than 40 items),
such as:
- Vernon, McKay. Rubella and Deafness Published around 1968 by the National Association of the Deaf.
- Sigurjonsson, Julius. "Rubella and Congenital Deafness." American Journal of Medical Science, December 1961, volume 242. Photocopied article.
- Hopkins, Louise A. "Rubella-Deafened Infants: Comparison of a Group of Hereditarily Deaf Children and Their Sibs." Photocopied article from American Journal of Diseases of Children, August 1949, volume 78, no. 2.
Government Databases
These example articles on rubella and deafness
were found on either PubMed.gov or Eric.Ed.gov. Some of these articles have
abstracts available.
- "Mainstreaming and Postsecondary Educational and Employment Status of a Rubella Cohort." American Annals of the Deaf, Spring 1990, volume 135 number 1, pp. 22-6.
- "Effect of Maternal Rubella on Hearing and Vision: a Twenty Year Post-Epidemic Study." American Annals of the Deaf, July 1989, volume 134, number 3, pp. 232-42.
- "Postsecondary Programs for Deaf Students at the Peak of the Rubella Bulge." American Annals of the Deaf, March 1987, volume 132, number 1, pp. 36-42.
- "Autoimmunity in Congenital Rubella Syndrome." Journal of Pediatrics. March 1984, volume 104, Number 3, pp. 370-3.
- In 1980, there was a conference on rubella and deafness. The American Annals of the Deaf, volume 125, Number 8, November 1980, devoted an issue to the conference:
- An Evaluation of the United States Rubella Immunization Program
- But Don't Quote Me: Reflections by Parents on Deafness and Rubella.
- Deaf-Blind Children with Maternal Rubella: Implications for Adult Services.
- Deafness and Rubella: A Challenge and a Charge to Rehabilitation.
- Deafness and Rubella: Infants in the '60s, Adults in the '80s.
- Handicapping Conditions Associated with the Congenital Rubella Syndrome.
- Multihandicapped Deaf Students in Postsecondary Programs: Guidelines for Planning Services.
- Neurologic Damage and Behavior Disorder in Rubella Children.
- Projections for Deaf Students with Maternal Rubella: College and Other Alternatives.
- Reflections of a Deaf-Blind Adult.
- Rubella-Caused Deafness: Maintaining Objectivity and a Positive Frame of Reference.
- The "Rubella Bulge" and Vocational Planning.
- The Demographics of Deafness Resulting from Maternal Rubella.
------------------
--------------
ARTICLE:
Measles
Elimination in Canada
1.
1Immunization and Respiratory Infections Division, Centre for
Infectious Disease Prevention and Control, Population and Public Health Branch,
Health Canada, Otawa Canada
2.
2lnstitut National de Santé Publique du Quebec and Public Health
Research Unit, Laval University, Quebec Canada
3.
3National Microbiology Laboratory, Population and Public Health
Branch, Health Canada, Winnipeg cANADA
1.
Reprints or correspondence: Dr. Arlene King, Immunization and
Respiratory Diseases Division, Centre for Infectious Disease Prevention and
Control, AL#0602D, Tunney's Pasture, Ottawa, Ontario, Canada K1A 0K9 (arlene_king{at}hc-sc.gc.ca)
Abstract
To describe the progress and challenges in achieving measles
elimination in Canada, we analyzed national data on measles cases for
1998–2001. To assess the status of measles elimination in Canada, we estimated
the effective reproductive number, R. Measles elimination was
defined as the interruption of endemic transmission and failure to reestablish
endemic transmission after importation. Twelve isolated cases, 29 cases (72.4%
were linked to 2 outbreaks), 199 cases (96.9% were linked to 4 outbreaks of 2,
6, 30, and 155 cases), and 34 cases (73.5% were linked to 8 outbreaks of 2, 2,
2, 2, 3, 3, 3, and 8 cases) were reported in 1998, 1999, 2000, and 2001,
respectively. R
ranged
from 0.58 to 0.95. Multiple chains of transmission occurred in religious
communities that actively oppose or resist immunization efforts.
Epidemiological and virological evidence suggests that endemic transmission of
measles has been mostly interrupted since 1998.
Measles elimination lias been a recommended national objective in
Canada for >2 decades. In 1980, the National Advisory Committee on
Immunization stated that the goal of elimination of indigenous measles was
important and desirable [1]. In 1994, the Canadian Ministry of Health joined other Pan
American Ministries of Health to set a target of measles elimination in the
Western Hemisphere by 2000 [2]. Here we describe the progress and challenges in achieving this
goal, with a focus on the period 1998–2001.
HISTORY OF MEASLES IN
CANADA: 1924–1997
Measles has been a reportable disease in Canada since 1924, with
the exception of a period from 1958 to 1969, during which time measles was not
nationally reportable. In the prevaccine era, measles occurred in 2- to 3-year
epidemic cycles (figure
1). The highest incidence was reported in 1935, with >83,000
cases (770/100,000 population). Deaths from measles complications were very
common in the early 1900s; in 1926, there were 892 measles-associated deaths,
the highest ever reported [3].
Live measles vaccine was licensed in Canada in 1963, and by the
early 1970s, publicly funded 1-dose immunization programs, routinely given at 1
year of age, had been introduced across Canada [4]. Before 1970, killed measles vaccine was used in 2 provinces. In
1970, this practice was discontinued when it was determined that this vaccine
could cause atypical measles syndrome [4]. Revaccination with the live attenuated vaccine was subsequently
recommended [5].
No reliable national estimate of vaccine coverage was available
until 1993. From available provincial data, it appears that measles vaccine was
not used widely until the early 1970s, but national coverage was assumed to be
>85% by the late 1970s [6]. In the late 1980s, after "catch-up" immunization of
school entrants, immunization coverage ranged from 95% to 100% [7]. However, despite virtually 100% documented 1-dose coverage in
some regions, large outbreaks of measles involving thousands of cases
persisted, mostly in school-aged children [8, 9]. From 1990 to 1997, the number of cases reported annually ranged
from 204 (1993) to 6178 (1991), with a median of 808 cases and an average of
1745 cases (6.1/100,000 population). An increasing proportion of cases occurred
among older children or young adults who had received only 1 dose of measles
vaccine. Clearly, because of primary vaccine failure, Canada's 1-dose program
was insufficient to interrupt endemic transmission.
In 1992, participants at a national consensus conference on
measles endorsed the goal of measles elimination and set a target date of 2005.
The major change in the measles elimination strategy was the recommended
addition of a routine second dose of measles vaccine before school entry [10]. In 1995, Canada was the only country in the region of the
Americas that had not added a second dose or catch-up program to the routine
1-dose immunization program. That year, with only 3.6% of the population of the
region, Canada recorded 2362 cases of measles, which represented 40% of all
reported cases in the region [11]. This discrepancy was largely due to individuals who lacked
protection after 1 dose of vaccine given at 12 months of age. In 1996–1997, in
response to this relatively high measles incidence, 2-dose measles vaccine schedules
were adopted across the country, and catch-up campaigns involving school-aged
children and adolescents were completed in most jurisdictions. Enhanced measles
surveillance was introduced. A national Working Group on Measles Elimination
(WGME) was established to oversee measles elimination activities, to review
cases, and to recommend modifications to prevention and control strategies.
These included achieving and maintaining the highest possible population
immunity by providing 1 dose of measles-mumps-rubella (MMR) vaccine at 1 year
of age or as soon as possible thereafter and a second dose of MMR before school
entry (at age 18 months or 4–6 years); enhancing surveillance to ensure that
cases are investigated thoroughly (by epidemiological, serological, and
molecular methods); and promptly responding to cases and outbreaks by
identifying and immunizing susceptible persons who are exposed to measles or at
risk of exposure to measles.
Although the total absence of cases is the general understanding
of elimination, this is not achievable in the absence of global eradication.
Most importations from countries with less control over measles are not
preventable, and secondary spread should be expected unless everyone is fully
protected.
However, if high population immunity is maintained, secondary
transmission will quickly cease [12]. To assess our progress toward elimination, our working
definition of elimination was the interruption of endemic measles transmission
and failure to reestablish endemic transmission after importation. Here we
describe the epidemiological observations between 1998 and 2001 and assess the
status of measles elimination in Canada.
METHODS
We analyzed epidemiological data on individual cases and outbreaks
obtained from the national Notifiable Disease Reporting System and enhanced
measles surveillance system from 1998–2001. Data on all case and outbreak
reports are received on a weekly basis from provincial and territorial health
departments and are reviewed, collated, and analyzed by the Division of
Immunization and Respiratory Diseases, Health Canada. All case and outbreak
reports are reviewed annually by the WGME. Although all suspected cases of
measles are investigated by local public health authorities in Canada,
generally only confirmed cases are reported nationally. Confirmed cases of
measles require laboratory confirmation of infection in the absence of recent
immunization with measles-containing vaccine as follows: isolation or detection
of measles virus from an appropriate clinical specimen, seroconversion or
significant rise in measles-specific antibody titer between acute and
convalescent sera, or positive results of serological testing for measles IgM
antibody by means of a recommended assay [12]. In the absence of an epidemiological link or if the clinical
presentation is inconsistent with a diagnosis of measles, IgM results must be
confirmed by additional testing with either isolation or seroconversion from
acute to convalescent sera. Measles serology is done in 17 laboratories across
Canada. Measles virus ge-notyping is carried out at the National Microbiology
Laboratory, Winnipeg [13].
For this analysis, only confirmed cases were used. Case reports
include demographic and geographic data, date of onset, diagnostic status
(laboratory confirmed or epidemiologically linked), outcome, immunization
history, and exposure-related data. Cases are defined as imported,
importation-related, or unknown-source. An imported case is one that occurs in
a patient exposed outside Canada, with rash onset occurring within 7–21 days of
entering Canada; illness cannot be linked to local transmission. An
importation-related case is one that is linked to an imported case but acquired
in Canada. An unknown-source case is a case of measles acquired in Canada,
unrelated to an imported case or for which a linkage could not be established
despite investigation. Data obtained from the molecular epidemiology of measles
virus isolated from cases are used to provide additional information concerning
the probable source of measles importation [12,13].
Outbreaks are defined as the occurrence of ⩾2 linked cases.
To assess the status of measles elimination in Canada during
1998–2001, we estimated the effective reproduction number, R. R is the
average number of cases spread from an individual case and is a summary measure
of the epidemic potential in a particular population [11, 14, 15]. R
was estimated according to the proportion of cases imported (R = I -
proportion of cases imported) and from the distribution of outbreak sizes [11]. The values of R
were estimated by maximum likelihood based on the Borel-Tanner distribution.
Approximate 95% confidence intervals were calculated by use of the profile
likelihood. For the calculations based on the proportion of imported cases, the
confidence intervals were truncated at a value of 1, because the method is
conditional on outbreaks becoming extinct. Cases were grouped into chains of
transmission on the basis of links found during the investigations. Chains in
which the source of importation was identified were classified as
importation-related, whereas others were of unknown source.
RESULTS
Since the introduction of routine 2-dose programs and catchup
campaigns in 1996–1997, the average annual incidence of measles has declined by
96% compared with 1990–1997. Multiple chains of transmission have occurred
exclusively in low-coverage religious communities that either oppose or resist
immunization. Cases and outbreaks are described below.
Twelve cases (0.04/100,000 population) of measles were reported in
1998; all were laboratory-confirmed and verified by the WGME. This was the
lowest number of cases ever recorded in Canada and compares with 581 cases
(1.9/100,000 population) in 1997. Ages of case patients ranged from 9 months to
33 years (median, 5 years). Five case patients had no history of measles
vaccination, 2 were vaccinated before their first birthdays, 4 had received 1
appropriately timed dose, and 1 had received 2 doses. Five cases were found to
be imported, and in the remaining 7 cases, despite investigation, the source of
infection was unknown.
Twenty-nine cases (0.09/100,000 population) of measles were
reported in 1999; 21(72.4%) were associated with 2 small outbreaks (table
1). The first outbreak, involving 4 cases, began with a visitor
from the Netherlands who developed measles on 30 July 1999, immediately after
his arrival in Canada. Three secondary cases (his 21-year-old sister and her 2
children, aged 23 and 11 months), occurring over 2 generations, were reported.
All case patients were unimmunized and belonged to a religious community that
opposes immunization. It was later learned that the index case patient had
visited an area of the Netherlands in which an outbreak of measles was
occurring [16]. The second outbreak, involving 17 case-3 generations- occurred
in another Canadian province in the same religious
Table 1.
Distribution of
outbreak size and estimates of the reproduction number, R, for
measles in Canada according to the proportion of imported cases and outbreak
size.
community that opposes immunization. This outbreak began after a
mother and her 3 children returned to Canada from the Netherlands. Measles
virus from this outbreak was isolated and determined to be of genotype D6 [13]. In addition to these outbreaks, 8 sporadic cases were reported,
6 in persons exposed outside Canada (India, Indonesia, Japan [2], Pakistan, and the Philippines). For the remaining 2 cases, the
source of infection was unknown.
In 2000, 199 cases were reported; 4 outbreaks (2, 6, 30, and 155
cases) accounted for 96.5% of all cases reported (table
1). The 2-case outbreak involved a 7-month-old infant who had
traveled to Pakistan and who was hospitalized in Canada with undiagnosed
measles. The epidemiologically linked case occurred in a hospitalized
14-month-old child whose measles immunization had been delayed because of an illness.
The 6-case outbreak spanned 6 weeks. All case patients were unim-munized and
reported philosophical objections to immunization. The index patient, a
14-year-old girl, visited Mazatlan, a tourist area in Mexico, during 10–24
March 2000. She started to develop rash on 8 April. The family did not seek
medical attention but the girl was kept home from school. The first generation
of spread in Canada included 2 cases, with rash onsets on 18 and 22 April.
These cases occurred in the 11-year-old sister and a 14-year-old contact of the
girl. The second generation of spread resulted in a case in the index patient's
18-year-old sibling, who lives in another town and who became ill on 1 May. In
the third generation of spread, the 18-year-old's 2 roommates (noninstitutional)
became ill with rash onsets on 13 and 15 May. Both roommates were 21-year-old
women. One of the roommates went to the emergency ward of a nearby hospital,
which notified the local health department. This was the first patient in this
cluster to receive medical attention and, thus, this was the first case to be
reported to public health. Health Canada immediately notified the Pan American
Health Organization (PAHO). After the chain of transmission was traced back to
the index case patient who had visited Mazatlan, no measles activity
potentially linked to the index case was identified in Mexico. Direct detection
of measles virus in nasopharyngeal and urine specimens by reverse
transcriptase-polymerase chain reaction was done, and the virus was determined
to be of genotype D7 [13]. Importantly, the genotyping results indicated no genetic
similarities with the D6 measles strain found in South America.
The third outbreak in 2000, involving 155 cases in a religious
community that resists immunization, began in Alberta and later spread to the
same religious community in British Columbia. Case patients ranged in age from
<1 year to 34 years (median, 7.3 years). Children aged <10 years
accounted for 59% of the cases, including 8 infants. The outbreak started on 21
May, peaked in September, and lasted until 9 October, a span of 20 weeks, ∼10
generations. The index case patients were 2 unimmunized siblings, aged 2 and 3
years, with rash onsets on 21 and 25 May. The children had traveled with their
parents to an affiliated religious community in Bolivia and returned to Canada
on 11 May. Members of this Canadian religious community frequently travel to
Bolivia to visit affiliated communities. Several closely linked families in the
religious community in Canada were involved in this outbreak. Two families from
the measles-affected Alberta religious community and 1 family from the
affiliated Bolivian community attended a large social gathering in British
Columbia on 13 June. After the gathering, 4 families in the British Columbia
religious community developed measles, with subsequent spread to other families
in the same community. Measles virus isolates were obtained from both the
Alberta and British Columbia communities and were determined to be identical to
the D6 strain circulating in South America [13]. On 1 June 2000, in the absence of preexisting measles activity
in this area of Canada, Health Canada notified PAHO of the Canadian outbreak.
Investigation by the Bolivian Ministry of Health, assisted by the PAHO, led to
the tracing of the source of exposure to affiliated communities in the Santa
Cruz area of Bolivia, where >60 cases were identified. [17].
The fourth outbreak in 2000, involving 30 cases, occurred in
several families belonging to another semiclosed religious community in Quebec
(population, ∼2500). Case patients ranged in age from 7 months to 33 years
(median, 5.5 years). Children <10 years of age accounted for 21 cases (70%),
including 3 infants. The outbreak started on 8 May and lasted until 9 August, a
span of 13 weeks—6 generations. Screening of school records of 200 students in
the community indicated that only ∼75% had received 1 dose of measles vaccine,
whereas about half had received 2 doses of measles vaccine. Genotyping results
from this community indicate that the virus was of genotype D6, a strain
commonly found in Europe and South America [ 13
]. It was reported that this community often received visitors and students
from affiliated communities outside Canada, most recently from Belgium and New
York. In February–March 2000, an outbreak of 8 cases in New York was linked to
an outbreak in the United Kingdom [18].
Thirty-four cases (0.1/100,000 population) of measles involving 4
provinces were reported in 2001; 25 cases (73.5%) were associated with 8 small
outbreaks, ranging in size from 2 to 8 cases (table
1). Case patients ranged in age from 5 months to 38 years (average,
18.5 years). Some cases in these outbreaks involved unimmunized siblings
following household exposure. Seven case patients (20.6%) had a documented
history of having received 1 dose of measles vaccine, and 3 (8.8%) were infants
<1 year old, too young to be eligible for routine measles vaccination. At
least 7 case patients required hospitalization or an emergency ward visit. The
first outbreak, involving 8 cases, began with a 15-year-old unvaccinated
foreign-born student who developed measles on 15 January 2001, 6 days after
returning to Canada after a holiday trip to his native country (Korea). He
attended a school of ∼750 students and lived in a community with a number of
families who oppose immunization for philosophical reasons. This index case
patient, who did not seek medical attention, was identified retrospectively
after several contacts who developed measles sought medical attention. Seven
secondary cases occurred, all involving school students 12–15 years of age. The
outbreak lasted 24 days—2 generations. Measles virus was genotyped as HI, which
is a strain found in Korea [13]. In addition, outbreaks involving 2–3 cases occurred after
importations from the following countries: Singapore (3 cases in Ontario,
genotype HI), Germany (3 cases in Alberta, genotype D5), New Zealand (3 cases
in Alberta, genotype D5; 2 cases in British Columbia), and Pakistan (2 cases in
British Columbia) [13]. For the remaining 2 outbreaks, the source was unknown (2 cases
in Ontario and 2 cases in Alberta). In addition to these outbreaks, 9 sporadic
cases were reported, 7 in patients exposed outside of Canada (Belgium, Germany,
India, Korea or Japan, Pakistan, the Philippines, and the United States). For
the remaining 2 single cases, the source of infection was unknown. Overall, 3
different genotypes of measles viruses were identified as associated with
importation in Canada in 2001—HI, D3, and D5 [13].
In summary, between 1998 and 2001, Canada had a total of 36 chains
of transmission with a known source of importation and 13 with no source
identified (table
1). The distribution of outbreak size is bimodal, with 35 isolated
cases and 3 outbreaks involving >15 cases. Although all case chains in 2000
were found to be linked to importation, the source was unknown for 7, 2, and 2
isolated cases in 1998, 1999, and 2001, respectively. The proportion of
reported cases that were imported decreased from 42% to 5% between 1998 and
2000 and increased to 38% in 2001. The lower proportion of imported cases in
1999–2000 was mainly due to the 3 large outbreaks in low-coverage religious
communities. R
estimated for 1998–2001 from the proportion of imported cases was 0.87, whereas
R
was 0.82–0.86 as determined by outbreak size. In 2000, given the very large
outbreak, these values were nearly 1. The distribution of outbreak size between
1998 and 2001 did not fit the theoretical distribution expected for an R of 0.85 [11] (figure
2). With this value of R,
42% of importations would lead to no secondary spread; however, this happened
in 67% of chains (24/36) with a known source of importation. The lack of fit
between the observed and predicted distribution of outbreak size indicates a
clustering rather than homogenous distribution of susceptible persons in the
population.
Figure 2.
Observed and
predicted distribution of outbreak sizes, according to the effective
reproduction number R.
DISCUSSION
Epidemiological and virological evidence to date suggests that
endemic transmission of measles has been mostly interrupted. This evidence is
supported by the measles virus genotyping data, which show that a number of
different genotypes have been detected in Canada since 1998. Furthermore,
almost all reported cases have been imported or importation-related. Imported
cases have occurred in foreign visitors to Canada and Canadian residents
exposed to measles while abroad. Of the 36 incidents reported in Canada during
1998–2001 for which the source of importation was known, only 6 resulted in
transmission involving >4 cases. Long chains of transmission have occurred
exclusively in religious communities that actively oppose or resist
immunization efforts. Despite imported cases and outbreaks in certain religious
communities that continued for several generations, the absence of spillover
into the general population supports our belief that immunization coverage in
the general population is high and that population immunity is more than adequate
to prevent reestablishment of endemic transmission. However, limited
interaction between these communities and the general population may also have
been a factor in the limited spread. Regardless, it is recognized that measles
elimination will persist only if 2-dose measles vaccine coverage is maintained
at near 100% levels.
The presence of a few cases of unknown source and exclusion of
unconfirmed cases illustrates that not all cases have been reported. Although
it is theoretically possible that a chain of endemic transmission involving a
few cases has not been identified, we believe that this can be ruled out,
because cases with an unknown source were rare after 1998 and were identified
throughout the country, and no single genotype is evident [13]. Furthermore, the reduction in cases of unknown source since
1998 may suggest that surveillance improved over time and that few cases were
missed. Finally, a survey of all laboratories in Canada that perform measles
IgM testing indicated that 6586 (22/100,000 population) and 5255 (17/100,000
population) tests for measles IgM were done in 1998 and 1999, respectively.
This approximates the total number of suspected measles cases investigated in
Canada in those years and provides an estimate of the sensitivity of our
surveillance system.
The estimate of R
allows assessment of the risk of recurrence of sustained transmission in a
population [11]. From the distribution of outbreak size, R was
estimated to be 0.86 during 1998–2001 and 0.95 in 2000. Although this latter
value would normally signal a near return to sustained transmission, this was
not the case. A basic assumption of this method is the random distribution of
susceptible individuals in the population. This assumption can be assessed by
the distribution of outbreak sizes [11]. In contrast to the United States, where importation-related
outbreaks followed the predicted outbreak size distribution with no prolonged
disease transmission [15], in Canada the distribution was bimodal, with most importations
followed by no transmission, a few importations leading to large outbreaks, and
almost nothing in between. This and the fact that the theoretical distribution
of outbreak size for an R
of 0.86 does not fit the observed data indicates heterogeneity in the
population, with clusters rather than an even distribution of susceptible
persons, and an overestimate of R.
In the general population, the immunity is very high and R very low
(∼0.50–0.60), but this does not prevent transmission in clusters of persons
opposed to immunization. Whereas it maybe tempting to discard the approach of
estimating R
because of this caveat, the comparison of the theoretical and actual outbreak
size distribution is a robust way to determine whether the epidemiological
situation is driven by clusters of susceptible persons rather than by a more
generalized problem, information that is critical to designing an appropriate
intervention.
Improving vaccine uptake in low-coverage religious communities in
Canada has been challenging. Although some actively oppose immunization, others
maintain low-level resistance or are not aware of its importance. Community
leaders and members need to be advised that they often are at greater risk of
importation of diseases such as measles because of frequent travel between
affiliated communities in different countries. Furthermore, they are often
members of large, closely knit families—an environment that facilitates measles
transmission and that necessitates extremely high coverage rates. Although
public health access to these communities is often limited, some have responded
to special approaches, such as obtaining endorsement of immunization by
religious leaders. These outbreaks remind us of the need to establish good
working relationships with these communities to ensure rapid sharing of
information on disease activity and acceptance of recommended public health
interventions. They also remind us of the importance of prompt international
dissemination of information about outbreaks of vaccine-preventable disease and
of effective methods to reach special groups, such as these religious
communities, to improve immunization coverage.
In 2000, Canadian residents took 4.5 million trips overseas;
overseas visitors (nonresidents) made an additional 4.4 million trips into
Canada (M. Campbell, Statistics Canada, 2001, personal communication). Clearly,
importation of measles by susceptible Canadian residents and foreign visitors
will continue to occur until global eradication has been achieved. Health
Canada recommends that international travelers should have up-to-date routine
immunizations. Two documented doses of measles vaccine are recommended for all
international travelers aged ⩾1 year who were born after
1970, unless there is serological proof of immunity or physician documentation
of prior measles [2]. Monovalent measles vaccine should be given to infants ⩾6 months of age when traveling abroad [2]. There are currently no vaccination requirements for immigrants,
refugees, or visitors to Canada, but all Canadian residents have access to
publicly funded measles vaccine.
The recent history of measles in Canada illustrates the continuing
challenges of maintaining disease elimination in the absence of global
eradication. Although our progress is cause for quiet celebration by Canadian
parents, public health practitioners, clinicians, and policy makers, it is also
cause for introspection. It reminds us of some of our challenges—conducting
effective disease surveillance, mounting rapid responses to cases and
outbreaks, and measuring and maintaining high, broad-based 2-dose coverage
rates. Sustaining our success will require innovation and continued
international cooperation and political will. All this occurs in an environment
in which perceived and real vaccine safety issues are now more visible than the
disease itself. Epidemics, after all, may be only a plane ride away.
Elimination, unless we sustain vaccine coverage, is potentially here today and
gone tomorrow.
MEMBERS OF THE WORKING
GROUP ON MEASLES ELIMINATION
Chair, John Waters, Health Strategies Division, Alberta Health
& Wellness, Edmonton, Canada (deceased); Monique Douville-Fradet,
Prevention et protection de la santé publique, Ministére de la santé et des
services sociaux, Quebec; Joanne Embree, Department of Medical Microbiology,
University of Manitoba; Victor Marchessault (deceased), National Advisory
Committee on Immunization; and Sam Ratnam, Newfoundland Public Health
Laboratories.
Acknowledgments
We thank the heroes of measles elimination in Canada-
provincial/territorial and local public health personnel, laboratory personnel,
health care providers-for their ongoing contributions to measles elimination in
Canada and for their timely investigation and reporting of all measles cases.
We also thank Jassy Anthony, Division of Immunization and Respiratory Diseases,
Health Canada, for assistance with the collection, collation, and analysis of
enhanced measles surveillance data. We gratefully acknowledge Paddy Farrington,
Nigel Gay, Mark Pa-pania, and Mary McCauley for manuscript review and
constructive feedback.
Footnotes
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in Canada-1986 update.
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Measles
in Canada: surveillance summary. Can Dis Wkly Rep 1979;5:121-127.
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Advisory Committee on Immunization
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----
A little good news- CANADA'S Anne Murray 1983-
AND... USA
Measles Timeline
With all of the current measles
outbreaks, measles is obviously not just a disease of the past. That makes
it important to learn about the history of measles so that we don't repeat past
mistakes, like the low immunization rates that led to the large measles
outbreaks from 1989 to 1991.
Measles has likely been around since the 9th
century. The more recent history of measles includes:
- 1772 - over 900 children in Charleston, SC die in a measles outbreak
- 1846 - Peter Panum publishes some of the research about measles epidemics
- 1865 - 5,000 soldiers in the Civil War die from measles
- 1918 - more than 2,000 soldiers in World War I die from measles
- 1920 - 469,924 cases (7,575 deaths) in the United States
- 1941 - 894,134 cases
- 1954 - measles virus isolated by Thomas Peebles, MD
- 1958 - first measles vaccine is tested
- 1962 - 503,282 cases - 432 measles deaths
- 1963 - first live measles vaccine licensed
- 1968 - improved live measles vaccine licensed
- 1969 - 25,826 cases - 41 measles deaths
- 1970 - 47,351 cases - 89 measles deaths
- 1971 - MMR vaccine introduced
- 1978 - 26,871 cases - 11 measles deaths (measles targeted for eliminated in U.S. by 1982)
- 1979 - 13,597 cases - 6 measles deaths - 30 SSPE deaths
- 1983 - 1,497 cases
- 1986 - 6,282 cases
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