| Overview
of Influenza Hospitalization Surveillance
The California Emerging Infections Program (CEIP) conducts active,
laboratory-based surveillance for all laboratory confirmed influenza
cases hospitalized in our three-county catchment area. For every
case identified, we will complete a CDC generated case report
form. These data will be entered into a CDC generated database,
and transmitted to CDC on a monthly basis.
Project
Objectives
- Characterize the burden of and risk factors for laboratory-confirmed
influenza-associated
hospitalizations in a timely manner;
- Describe clinical and epidemiologic characteristics of hospitalized
case-patients;
- Conduct special studies (such as influenza vaccine effectiveness)
using the surveillance catchment area as a platform. Main
Components of Influenza Hospitalization Surveillance Project
-Active laboratory based surveillance
-Special study: Adult Seasonal Influenza Vaccine Effectiveness
Study
-Special Study:
nH1N1 Influenza
Vaccine Effectiveness Study
Case
Definition
-
A resident of the catchment area
- Admitted to a catchment area hospital between Oct 1 and April
30
- Admitted to hospital 3 days before or within 14 days after
a positive influenza test
- Evidence of a positive influenza test
- Case defining influenza tests include:
- A viral culture
- Immunofluorescence antibody staining (Direct [DFA] or indirect
[IFA])
- Reverse transcriptase polymerase chain reaction (RT-PCR)
- A commercially available rapid diagnostic test for influenza
Current Influenza Projects
On June 11, 2009 The World Health Organization declared novel
H1N1 Influenza A to be pandemic in response to the rising number
of cases. This new H1N1 subtype of the Influenza A virus has never
before been seen in humans and therefore we, as a population,
have little immunity to it. Since the nH1N1 strain emerged, state
and local health departments have been focusing on Influenza A
surveillance and subtyping. to determine the incidence of disease
caused by nH1N1 virus. The Emerging Infections Programs’
surveillance has focused on documenting subtype information for
hospitalized Influenza A cases. We have also launched a new nH1N1
Vaccine Effectiveness Study; more information about that can be
found below.
The nH1N1 Influenza Vaccine Effectiveness Study: Part of a multi
site case control study being conducted in collaboration with
Centers for Disease Control Influenza Division and nine other
Emerging Infections Programs nationwide. This study includes people
over the age of 6 months and began once we estimated that 10%
of the population had been vaccinated for nH1N1 influenza; in
California, pediatric case enrollment began November 20, 2009
and adult case enrollment began January 1, 2010. Study enrollment
will continue through May,2010. Eligible cases are those who were
hospitalized with laboratory-confirmed, community-acquired nH1N1
influenza illness within 14 days of nH1N1 influenza diagnosis.
For each enrolled case, project personnel will recruit two age
and residence matched controls who have not been hospitalized
for influenza or for an acute respiratory condition during the
influenza season. Study personnel will enroll cases and controls
using a standardized telephone interview in either Spanish or
English. We will collect information for each participant about
influenza vaccine status and factors known to increase the risk
of serious complications from influenza infections. The goal of
the study is to determine how effective the nH1N1 vaccine has
been in preventing hospitalizations with nH1N1 influenza illness
in different age groups.
The Adult Seasonal Influenza Vaccine Effectiveness Study: Part
of a multi site study being conducted in collaboration with Centers
for Disease Control Influenza Division and nine other Emerging
Infections Programs nationwide. This study began October 1, 2008
and will continue for three consecutive influenza seasons. Eligible
cases are adults 50 years and older, hospitalized with a laboratory-confirmed,
community-acquired influenza illness within 14 days of influenza
diagnosis. For each enrolled case, project personnel will recruit
two age and residence matched adults who have not been hospitalized
for influenza or for an acute respiratory condition during the
influenza season. Study personnel will enroll cases and controls
using a standardized telephone interview in either Spanish or
English. We will collect information for each participant about
influenza vaccine status and factors known to increase the risk
of serious complications from influenza infections.
Links
CDC Influenza
Information
California
Department of Public Health California Influenza Surveillance
Project
California
Department of Public Health H1N1 Influenza Site
California
Department of Public Health Diagnostic Testing for Novel Influenza
A H1N1
World
Health Organization’s H1N1 information
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