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Published Date: 2007-05-11 19:00:02
Subject: PRO/EDR> Measles - Switzerland (Geneva)
Archive Number: 20070511.1513

MEASLES - SWITZERLAND (GENEVA)
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Date: Thu 10 May 2007
Source: Eurosurveillance weekly release 2007; 12(5) [edited]
<http://www.eurosurveillance.org/ew/2007/070510.asp#2>

Outbreak of measles in Geneva, Switzerland, March-April 2007
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Introduction
------------
Between 1 Mar and 5 Apr 2007, 11 cases of measles were notified in the
canton of Geneva, Switzerland. The most recent cases before this cluster
dated back to April 2005. In Switzerland, measles notification by
physicians and laboratories to local and federal public health authorities
is mandatory. A clinical case of measles is defined as a patient presenting
with rash and fever greater than 38 deg C (100.4 deg F) as well as one of
the following: cough, coryza, or conjunctivitis. A confirmed case is a
clinical case with positive specific IgM and/or a positive PCR test, or a
clinical case with a clear epidemiological link to a laboratory-confirmed
case. In 2006, the maximum allowed delay for notification of cases to
health authorities was reduced from one week to 24 hours from diagnosis. In
Switzerland, measles vaccination was introduced in 1969 and included (one
dose) in the national immunisation plan in 1987. A 2nd dose has been
recommended at 4 to 7 years of age since 1996, and at 15-24 months since
2001. Measles vaccination is not mandatory, and overall coverage of 24-35
month old infants was 82.3 per cent in 1999-2003 [1].
Outbreak description
--------------------
The 1st case was a 14 year old boy who presented on 26 Feb 2007, with fever
and coryza, and developed conjunctivitis and rash on 2 Mar 2007. He was
hospitalised on 2 Mar 2007 with measles-related pneumonia. On 28 Feb 2007,
a 16 year old girl from the same neighbourhood presented with fever, cough,
and conjunctivitis. She developed a rash on 3 Mar 2007, and was
hospitalised the same day. The source of infection for these 2 index cases
is unknown. Although they lived in the same neighbourhood, there was no
evidence they came in contact with each other. However, both had been on
vacation during the incubation period: the 1st case was in Saanenmoeser
(Bern canton) from 11 to 17 Feb 2007; the 2nd case was in Rougemont (Vaud
canton) from 10 to 17 Feb 2007. These 2 localities are 10 km (6.2 miles)
apart. No measles cases with onset during that period were reported in
either of these 2 cantons, but 2 cases with onset after 26 Feb 2007 were
reported in Bern canton.
[In the original text] the epidemic curve is presented as Figure 1. Between
6 Mar and 5 Apr 2007, 9 additional cases were notified in Geneva. Cases
were grouped in 2 clusters of 8 ("cluster A") and 3 cases ("cluster B"). Of
the cases, 8 lived in the same neighbourhood, 5 of them in the same
building. All cases were confirmed with either serology or an
epidemiological link with a confirmed case (one case). During the outbreak
period, 3 additional suspected cases were notified, but were ruled out as
they had negative serology. No additional case [was notified until 30 Apr
2007].
Most cases (73 per cent) were between 10 and 19 years of age. Other cases
were aged 2, 6, and 30. The median age was 16 years. The age distribution
of the cases is presented [as a figure in the original text]. The
immunisation status is known for 10 of the 11 cases, none of who was
vaccinated (refusal for 9 cases and parental request for delayed
vaccination for the 2 year old infant). Four patients (36 per cent) were
hospitalised for pneumonia and/or general malaise and weakness, with one
teenage girl requiring intensive care. All patients recovered. The average
duration of hospitalisation was 4 days. Four cases had complications
including pneumonia (2 cases) and otitis media (2 cases).
All cases were grouped in 2 chains of transmission of 8 (cluster A) and 3
cases (cluster B). Transmission occurred within the household (3 cases),
among persons living in the same building (2 cases), because they were
friends and spent time together (3 cases), and in a hospital waiting room
(one case). No transmission occurred in schools or day care centres. Three
generations of cases were identified.
Laboratory results
------------------
Ten of the cases were confirmed by serology. Genotyping was conducted for 4
cases. One was not conclusive, and genotype D5 was identified for the other
3. D5 genotype is currently associated with a large outbreak in the canton
of Lucerne with more than 100 cases [2]. However, none of the 2 index cases
could be linked to this outbreak.
Control measures
----------------
Contact tracing was conducted for every case to identify the source of
infection and inform known contacts about their exposure. Those identified
within 72 hours of exposure, with no history of measles or measles
vaccination, were offered and received vaccination (2 persons) or
immunoglobulin (2 persons). Unvaccinated siblings of cases were requested
not to go to school for 10 days after disease onset of their brother/sister
[3]. Other contacts were encouraged to consult their physician in case of
symptoms. All contacts were followed up to ascertain whether they had
developed disease. In addition, school health services sent letters to
parents of all schools and day care centres where a case had occurred.
Information on the outbreak and the need to vaccinate infants as early as 9
months of age in the context of this outbreak was posted in all day care
centres in the canton of Geneva. All physicians of the canton were also
informed via email and reminded of the importance of diagnosis and early
notification. The population was also informed with several articles in
news media.
Discussion
----------
This is the 3rd outbreak of measles in the canton of Geneva since 2003.
There were 54 cases in 2003 [4] and 16 cases in 2005 [5-7]. Several factors
may play a role in the decreasing number of cases: the shortening of the
delay of notification, aggressive control measures, contact tracing and
exclusion from school of unvaccinated siblings of cases, increasing measles
vaccination coverage, and recommendation of vaccination or immunoglobulin
to unimmunised contacts. In 2003, the average delay of declaration for the
1st 15 cases was 2 weeks. The delay decreased in 2005, and was less than 2
days on average in the current outbreak. Six cases were notified within
hours of diagnosis. Exclusion from school of unvaccinated siblings
concerned 3 brothers and sisters of the index cases. All 3 developed
measles despite post-exposure prophylaxis (one case) or vaccination (2
cases), but did not transmit the infection as they where not in school
during the incubation period. In Geneva, immunisation coverage is monitored
by a vaccination card for all children from the age of 28 months [8].
Between the years 2000 and 2005, measles vaccination coverage with one dose
increased from 87.9 per cent to 91.5 per cent for children at 28 months of
age. For 2 doses, coverage was 81.7 per cent in 2005. Aggressive
case-finding and quickly providing information to parents, physicians, and
the public may also have played a role in controlling this outbreak.
References:
1. Lang P, Piller U, Steffen R. Vaccination coverage of children in
Switzerland, 1999-2003. University of Zurich, Institute of Social and
Preventive Medicine. Zurich, 2005.
2. Anonymous. Deux flambees de rougeole dans le canton de Lucerne avec 32
cas jusqu'a present. [in French] Bull OFSP 2007; 1:10-1.
3.Recommandations romandes et tessinoises d'eviction (pre)scolaire pour
maladie transmissible. [in French] Paediatrica 2005; 16(5): 45-8.
4. Delaporte E, Wyler CA, Richard JL, Sudre P. Contribution of unvaccinated
siblings to a measles outbreak in Switzerland [Contributions des fratries
non vaccines a une flambee de rougeole en Suisse]. [in French] Rev
Epidemiol Sante Publique 2004; 52(6): 493-501.
5. Aramburu C, Attinger M, et al. Two parallel outbreaks? Measles in Geneva
Health-care and school-associated measles in Switzerland. EPIET scientific
seminar Menorca 2005.
6. Hugonnet S, Uckay I, et al. Rougeole et plan strategique institutionnel
en cas d'epidemie. [in French] Swiss-NOSO Bull 2005; 12(1): 5-8.
7. Uckay I, Sax H, Hugonnet S, Aramburu C, Bessire N, Rutschmann O, et al.
Consequences of an insufficient range of immunity in pediatric infectious
diseases -- example with measles. Ther Umsch 2005 ; 62(10): 679-84.
8. Golay M, Sudre P. Immunization of 28 months old children in Geneva,
Switzerland: trend over a 6-year period, 1995-2000. Soz Praventivmed 2005;
50(5): 319-23.
[byline: E Delaporte, CA Wyler, P Sudre]
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ProMED-mail
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[This report illustrates that outbreaks of measles can be controlled
effectively by aggressive case tracing and rapid dissemination of
information to health care personnel and the general public. - Mod.CP]

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