| Substantial progress has been made within the World
Health Organization European Region in recent years towards the measles
and rubella elimination targets for 2010. These 2010 targets were set in
2005 by the WHO European Regional Office for Europe, following the approval
of the Resolution EUR/RC55/R7 [1,2]. In 2005, 28 (54%) of 52 WHO member
states reported a measles incidence of < 1 per million population (one
indicator for measuring measles elimination status) and by 2006, 50 (96%)
had introduced rubella vaccine into their national programmes. In 2002,
member states began reporting measles cases by age and vaccination status
to WHO on a monthly basis [3] and case-based reporting was implemented
in 2003. Since that time, the number of countries reporting case-based
data has increased from one in 2003 to 23 in 2006. In 2006, countries have
been asked to report rubella cases monthly (either aggregate or case-based).
The WHO European Region measles/rubella laboratory network has also been
strengthened through regular laboratory assessments and proficiency testing
and by having subregional meetings.
The past two years have been challenging, with several large outbreaks
in the European Region. The outbreaks in Romania and the Ukraine
[4] were the source of measles outbreaks in a number of EU countries,
including Estonia, Germany, Lithuania, Portugal, Poland and Spain.
These primary and secondary outbreaks have identified susceptible
people in some countries which had already achieved very good levels
of measles control. The outbreaks have also demonstrated the current
capacity for investigation at the local level, including the collection
of laboratory specimens for virus isolation/ detection, and the
capabilities of the measles/rubella laboratory network for tracking
specific measles virus genotypes and subtypes.
The paper in this issue of Eurosurveillance [5] describing the measles
outbreak in La Rioja identifies some of the challenges faced by countries
in the European Region as we move towards measles elimination. All countries
need to have strong epidemiological surveillance in place to detect importations
rapidly and allow quick response to outbreaks when they occur. The ability
to epidemiologically and virologically link measles cases with a source
is critical for assessing the interruption of endemic transmission within
and between countries in the European Region. The D6 measles virus genotype
causing disease in La Rioja was genetically identical to the strain causing
disease in the Ukraine, based on the sequence of the 450 nucleotides
of the C-terminus of the N (nucleoprotein) gene, the single most variable
part of the measles genome.
The importance of healthcare workers being immune to measles is
demonstrated in the La Rioja outbreak. Many healthcare workers
may have received none or only one dose of measles vaccine, yet
they have not been exposed to measles because virus circulation
has diminished with vaccine use. Ensuring that all healthcare workers
are adequately protected is key to preventing healthcare-associated
infections. Immunisation records of healthcare workers should be
reviewed and careful consideration given to ensuring that all have
received two doses of measles vaccine, unless they were born well
before measles vaccine was introduced.
The high proportion of measles cases observed in children aged
15 months or younger is noteworthy, given this is younger than
the recommended age in La Rioja for the first dose of measles vaccine.
The most effective primary prevention strategies for measles among
those younger than the age of first dose are to ensure high levels
of immunity among older siblings and caregivers. Outbreaks such
as the one in La Rioja require that public health officials develop
interventions customised to meet the specific risk group based
on a thorough epidemiological investigation. Once the decision
has been taken to immunise infants at an age younger than the routine
first dose, it is also necessary to decide when the practice should
be discontinued. Outbreaks such as this could justify the decision
for countries where the first dose of measles vaccine is currently
given at 12 months not to further postpone the age of first dose,
at least until measles has been eliminated in the European Region.
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