Incidence of congenital rubella syndrome at a hospital serving a predominantly Hispanic population, El Paso, Texas

Objective. The current epidemiology of rubella reveals an increase in the n umber of cases among adult Hispanics and an increase in the number of conge nital rubella syndrome (CRS) cases among infants of Hispanic mothers. Recen t rubella outbreaks have occurred primarily among adult Hispanics, many of whom are foreign-born natives of countries where rubella vaccination is not routine or has only recently been implemented. The objective of this study was to estimate the incidence of CRS in a hospital serving a predominantly Hispanic population. Methods. Hospital charts of infants <1 year old discharged between January 1, 1994 and December 31, 1996 with International Classification of Diseases , Ninth Revision (ICD-9) discharge codes consistent with CRS were reviewed; we looked for cataracts, deafness, congenital heart defects, dermal erythr opoiesis, microcephaly, meningoencephalitis, and other defects associated w ith CRS. We abstracted data on maternal and infant ethnicity, maternal age, gestational age, infants' birth weight, infants' clinical characteristics, and laboratory evaluation. Cases were categorized according to the Council of State and Territorial Epidemiologists' case classification for CRS. Results. Of the 182 infants with 1 or more ICD-9 codes consistent with CRS, 6 (3.3%) met either the confirmed or probable case definition for CRS. Two infants met the definition for confirmed CRS. Although laboratory tests fo r rubella immunoglobulin M antibodies were positive for both of these infan ts, only 1 of the cases had been reported to the state health department. F our other infants had clinical presentations that met the definition for a probable case. One of these had been tested for rubella immunoglobulin M an tibodies, and the test was negative. The other 3 had not been tested. The r ate of infants meeting the definition of confirmed and probable CRS was 3.1 per 10 000 hospital births. All confirmed and probable cases were among in fants born to Hispanic mothers. Maternal country of origin was Mexico for t he 2 confirmed cases and 1 of the probable cases, and unknown for the remai ning 3 probable cases. Conclusions. The rate of confirmed and probable CRS among infants in this p redominantly Hispanic population is higher than the reported rate in the Un ited States in the vaccine era, which has been reported to range from appro ximately 0.01-0.08 per 10 000 live births. These findings indicate a need f or heightened awareness of CRS among physicians who serve populations at ri sk for rubella. Physicians should report all confirmed and probable CRS cas es to the state health department. The lack of appropriate laboratory testi ng in 3 infants with probable CRS indicates that physicians should consider a diagnosis of CRS in infants with some signs consistent with CRS, particu larly in areas serving high numbers of individuals at risk for rubella.