Adequacy of surveillance to detect endemic rubella transmission in the United States.
BACKGROUND
Reported rubella cases in the United States are at the lowest numbers since the introduction of vaccine, suggesting that endemic transmission may have been interrupted. It is necessary to validate that the observed absence of rubella is due to the disappearance of disease rather than a failure of rubella surveillance.


METHODS
Adequate rubella surveillance to detect ongoing transmission is characterized by evidence that rubella investigations are being conducted, detection of importations, and lack of spread from confirmed cases. We reviewed rubella surveillance data and activities from 5 sources: (1) data reported to the national surveillance system; (2) a survey of health departments and public health laboratories, including questions regarding any links between measles and rubella surveillance; (3) enhanced rubella surveillance activities in California and in New York City; (4) sentinel surveillance along the US-Mexico border; and (5) case detection in 8 large health maintenance organizations (HMOs).


RESULTS
During 2002-2004, 35 cases of rubella were reported to the national system, including 12 (34%) imported cases. The 39 programs that responded to our survey reported conducting 1482 investigations for rubella; according to another national survey, 1921 investigations were conducted for measles. Forty-one laboratories responded to our survey and reported conducting 6428 tests for acute rubella. No previously undetected (or unreported) cases of rubella or congenital rubella syndrome were identified by our survey or reviews of surveillance in California, New York, and along the US-Mexico border, and no additional cases were detected in the HMO database.


CONCLUSIONS
No previously unrecognized spread cases or outbreaks of rubella were detected. Surveillance in the United States is sufficiently sensitive to identify indigenous cases of rubella, if they were occurring, supporting the contention that rubella has been eliminated from the United States.
Averhoff
Francisco
F
National Center for Preparedness, Detection, and Control of Infectious Diseases (proposed), Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. fma0@cdc.gov
Zucker
Jane
J
Vellozzi
Claudia
C
Redd
Susan
S
Woodfill
Celia
C
Waterman
Steve
S
Baggs
James
J
Weinberg
Michelle
M
Rodriquez-Lainz
Alfonso
A
Carrion
Veronica
V
Goto
Collin
C
Reef
Susan E
SE
D018563:Disease Notification; D004196:Disease Outbreaks; D006801:Humans; D009313:National Health Programs; D011159:Population Surveillance / Q000379:methods*; D012409:Rubella / Q000175:diagnosis* / Q000453:epidemiology / Q000635:transmission*; D014481:United States / Q000453:epidemiology