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