Rubella Surveillance in California Celia Woodfill California Department
Rubella Surveillance in California Celia Woodfill California Department of Health Services Division of Communicable Disease Control Immunization Branch California Dept of Health Services Immunization Branch
Rubella Surveillance Objectives • To detect and to respond to cases and small chains of transmission • To prevent CRS cases • To prevent indigenous spread • To identify epidemiologic or virologic links to imported virus genotype(s) California Dept of Health Services Immunization Branch
Rubella and CRS Surveillance in California Health Care Provider notifies Local Health Department LHD conducts case investigation » Confirms diagnosis » Identifies source of infection » Identifies susceptible contacts LHD implements prevention and control measures LHD reports case to State Health Department Specimen forwarded to CDC for genetic sequencing California Dept of Health Services Immunization Branch
Adequacy of Rubella Surveillance 1. Sensitivity 2. Completeness of case investigations 3. Completeness of case ascertainment California Dept of Health Services Immunization Branch
Rubella Surveillance: Sensitivity • Capacity to detect individual cases and/or small chains of transmission • Capacity to rapidly detect and respond to outbreaks California Dept of Health Services Immunization Branch
Reported Rubella Cases are Spread Out in Space and Time, California 1996 – 2004 1996 2000 1997 2001 1998 2002 1999 2004
Rubella Surveillance: Outbreak Detection Imperial County School Outbreak, 2000 • In 2000, 2 rubella cases reported to LHD. • Cases were children (9 and 12 years old) who lived in Mexicali and attended a school in Imperial Co. • Apparently many of the students had received measles-only vaccine, rather than a vaccine that included rubella. • To prevent further spread, Imperial County HD offered MMR vaccinations to school students. • Only three other cases were identified (Mexicali children attending school in California) California Dept of Health Services Immunization Branch
Rubella Surveillance: Completeness of Case Investigations • Laboratory testing of suspected cases • Proportion of chains of transmission with known imported source California Dept of Health Services Immunization Branch
Rubella Surveillance: Diagnostic Laboratory Testing Public Health Laboratories, California 2000 – 2004 Ig. M tests* Ig. M+ Ca cases 2000 66 5 6 2001 64 0 1 2002 41 3 3 2003 42 1 0 2004 40 0 2 * Test data are incomplete California Dept of Health Services Immunization Branch
Rubella Surveillance: Completeness of Case Investigations • Proportion of chains of transmission with known imported source 1. International travel history 2. Epidemiological link to an imported case 3. Virological link (imported virus genotype) California Dept of Health Services Immunization Branch
Rubella Surveillance Completeness of Case Ascertainment • Identification of additional cases during case investigations • Identification of additional cases from other sources California Dept of Health Services Immunization Branch
Rubella Surveillance: Numbers of Additional Cases Detected During Case/Outbreak Investigations 1996 1997 1998 1999 2000 2001 2002 2004 Routine Additional 30 2 12 1 2 0 4 0 6 0 1 0 3 0 2 0 Total 32 13 2 4 6 1 3 2
Review of California Birth Defects Monitoring Program Active Surveillance Data to Identify Possible CRS Cases, Central California 1999 -2001 Methods: Records of infants with the following conditions most commonly associated with CRS were reviewed: • Congenital rubella • Microcephaly • Atrial septal defect or ventricular septal defect • Cataracts or glaucoma **Children with deafness and hearing loss are NOT included in the registry** Results: No evidence of cases of congenital rubella syndrome in Central California (Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, Tulare counties) during the years of 1999 – 2001. California Dept of Health Services Immunization Branch Review conducted by John Harris, MD, MPH, Director, California Birth Defects Monitoring Program
Summary Sensitivity: Surveillance is sensitive enough to identify single cases and/or small chains of transmission. Completeness of case investigations since 2000: • 100% of our rubella cases have been laboratory confirmed. • Source of infection identified for 25% of cases. Completeness of case ascertainment: Level of case ascertainment appears to be high. California Dept of Health Services Immunization Branch
Conclusions • Surveillance for rubella and CRS appears to be adequate to detect sustained chains of transmission of rubella • Surveillance to determine the source of infection for cases and/or chains of transmission of rubella needs to be strengthened • Immediate notification of all suspect cases • Isolates to CDC for genetic sequencing California Dept of Health Services Immunization Branch
California Dept of Health Services Immunization Branch
Rubella Surveillance: Proportion of Reported Cases that are Laboratory Tested, 1996 – 2002 1996 1997 1998 1999 2000 2001 2002 Reported cases % lab tested 32 75% 13 92% 2 100% 4 100% 6 100% 1 100% 3 100%
Epidemiology of Rubella and CRS in California • Surveillance for rubella and CRS • Population immunity to rubella • Evidence that transmission of rubella has been interrupted California Dept of Health Services Immunization Branch
Rubella Surveillance: Lab Testing of Suspect Cases 20 Local Health Departments, California 2000 – 2003 Number of Investigations 2000 34 % lab tested 79% 2001 16 81% 2002 10 70% 2003 6 100% California Dept of Health Services Immunization Branch
Rubella Surveillance: Febrile Rash Investigations Border Infectious Diseases Project, 2000 – 2003 San Diego/Imperial California 2000 2001 2002 2003 Ig. M tests 5 83 111 68 Ig. M+ 0 1 1 0 Tijuana/Mexicali Baja California Ig. M tests 43 15 28 94 Ig. M+ 8 1 0 1 United States-Mexico Border Region, Border Infectious Disease Surveillance Project
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