Epidemiology of rubella virus cases in the pre-vaccination era of Ethiopia 2009-2015.

Thursday, 24th of November 2016

BMC Public Health. 2016 Nov 18;16(1):1168.

Epidemiology of rubella virus cases in the pre-vaccination era of Ethiopia 2009-2015.

Getahun M¹ Beyene B² Gallagher K³ Ademe A³ Teshome B² Tefera M² Asha A² Afework A² Assefa E² HaileMariam Y² HaileGiorgis Y³ Ketema H² Shiferaw D² Bekele A² Jima D² Kebede A².

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Abstract

BACKGROUND:

Rubella is a common mild rash illness caused by rubella virus. The majority of infections occur in children and young adults. The infection is the cause of a serious birth defect known as Congenital Rubella Syndrome (CRS) when a woman acquires infection early in pregnancy. Ethiopia has not yet established rubella virus surveillance and has not yet introduced rubella vaccine into the routine immunization program. We characterize the epidemiology of laboratory confirmed rubella virus cases collected through measlessurveillance from 2009 to 2015 to better understand the burden of the disease in the country.

METHODS:

A descriptive analysis was made to characterize rubella cases reported through the national measles case based surveillance system. The measles case definition was used to capture potential rubella cases. A suspected measles case was a person with generalized rash and fever with cough or coryza or conjunctivitis. Those cases whose sera were negative for measles IgM antibodies were tested for rubella IgM antibody. A confirmed rubella case was a person who tested positive for rubella IgM. Only laboratory confirmed rubella cases were analyzed in this article.

RESULTS:

Between 2009 and 2015 a total of 28284 serum/plasma samples were collected and tested for measles IgM antibody and 11151 (39.4%) were found positive. A total of 17066 measles IgM negative or indeterminate samples were tested for rubella virus IgM and 2615 (15.3%) were found positive during the same period. Of 2615 confirmed rubella cases 52.2% were females. The age of confirmed cases ranged from one month to 42 years with a mean age of 7.3 years. Three-fourth of all confirmed rubella cases were aged less than 10 years. The number of laboratory confirmed rubella cases linearly increased from 83 in 2009 to 856 in 2013 but dropped to 222 and 319 in 2014 and 2015 respectively. Higher number of cases occurred in the hot dry season (January through June) and in the central and western part of Ethiopia with 127 lab-confirmed outbreaks in the study period.

CONCLUSIONS:

Based on our analysis rubella was found to be endemic throughout Ethiopia. Children below the age of 10 years were the most affected. The burden of rubella cases varied from year to year but had a seasonal peak in March. To better understand the magnitude of rubella prior to vaccine introduction establishing rubella surveillance system conducting sero-prevalence studies among child bearing age females and establishing CRS sentinel surveillance among young infants are critical.