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Increase in notified acute respiratory infection clusters in nursing homes:Surveillance 2011 – 2012 in Paca, France
Teija Korhonen EPIET fellow, Cire Sud, Marseilles, FranceESCAIDE 24th October 2012
• About 750 nursing homes in Provence-Alpes-Côte d’Azur (Paca)
• Elderly people vulnerable
• Close living conditions
Background
• Recommendations by the High Council of Public Health in 2005
• Surveillance system in Paca since 2005 in order to
– promote prevention efforts and influenza vaccinations– facilitate early cluster detection and guide control efforts– conduct epidemiological investigations when severe outbreaks
• Circular by the Ministry of Health in 2006
Surveillance history
• Describe notified acute respiratory infection (ARI) clusters in nursing homes in Paca in 2011 – 2012
• Compare characteristics to the four previous influenza seasons– explore trends
Objectives of this presentation
Person with a cough AND
at least one symptom from both lists: • dyspnea, chest pain, whistles, recent auscultatory findings
• fever, sweating, headache, joint pain, sore throat, nasal discharge
Case definition of ARI
• If three or more cases of ARI within eight days– residents and personnel
• Nursing home personnel reports to the Regional Health Office
• Information transferred to the national ARI surveillance database– weekly national and regional reports
ARI cluster surveillance
Number of notified ARI clusters in nursing homes by week of illness onset of the first case
in Paca October 2011 – April 2012
• 84 clusters: 1745 residents and 325 personnel ill
• 28% average AR for residents • 9% average AR for personnel
• 10% (137) of ill residents hospitalised• 5% (86) of ill residents died • At least one confirmed case of influenza in 60% of clusters• Influenza A(H3N2) identified in seven outbreaks
Results – surveillance 2011 - 2012
• Dominant type A(H3N2)– 1648 typed: 82% A(H3N2)
• 31% of A(H3N2) differed from the vaccine strain
* Bull Epidémiol Hebd. 2012;38:424-427
Results – virus types in France 2011 – 2012 *
Number of notified ARI clusters in nursing homes by influenza season
in Paca since 2007 - 2008
0
10
20
30
40
50
60
70
80
90
2007-2008 2008-2009 2009-2010 2010-2011 2011-2012
INFLUENZA SEASONS
NU
MB
ER
OF
CLU
ST
ER
S
Results – comparison with previous seasonsInfluenza virus types in France since 2007
Season Predominant strains %
2007 - 2008 A(H1N1) – influenza B 60 – 40
2008 - 2009 A(H3N2) 80
2009 - 2010 A(H1N1)pdm09
2010 - 2011 A(H1N1)pdm09 – influenza B 50 – 40
2011 - 2012 A(H3N2) 80
Significant p-values (< 0.05)
Results – comparison with previous seasons
2011 - 2012 Mean of 2007 - 2011
Number of clusters 84 34
Case-fatality (%) 5 2.8
Clusters with at leastone confirmedinfluenza case (%)
60 12
Largest amount of notified ARI clusters since the implementation ofthe surveillance system
• Circulation of A(H3N2)– first time predominant virus since season 2008 – 2009– one third variant from the vaccine strain
• Increased cluster-ascertainment – better familiarisation with the system
– potential underreporting
Discussion
• Explore reasons for non-participation to increase reporting
• Investigate possible differences in ARI outbreak management between participating and non-participating nursing homes
• Evaluate ARI surveillance at the regional and national level
Recommendations
• Personnel of the participated nursing homes
• Caroline Six, Francis Charlet, Philippe Malfait and other colleagues in the InVS and the Regional Health Office in Paca
• Kostas Danis and Ioannis Karagiannis
Acknowledgements