Burden of Congenital Rubella Syndrome (CRS) in India: a systematic review

Rubella, though a mild, vaccine-preventable disease, can manifest with severe teratogenic effects in the fetus labeled as congenital rubella syndrome (CRS) due to primary maternal rubella infection. Despite a reduction in disease burden of several vaccine-preventable diseases through childhood immunization, CRS continues to account for preventable severe morbidity including childhood blindness, deafness, heart disease, and mental retardation.

To conduct a systematic review to describe the prevalence of CRS and its contribution to major long-term handicaps in Indian population. Another objective was to estimate the susceptibility to rubella infection in Indian adolescent girls and women of reproductive age-group. We also explored strategies to decrease CRS in India by identifying the immunogenicity of rubella containing vaccines (RCV) in Indian children and women, as well as their coverage in India.

Publications reporting CRS prevalence in general population as well as selected subgroups i.e., suspected intra-uterine infection, congenital ocular abnormalities, deafness, congenital heart disease, mental retardation, and congenital malformations, seroprevalence to rubella (IgG) amongst women and adolescents, and immunogenicity and coverage of RCVs in Indian population were retrieved through a systematic search. Primary databases employed were Medline through PubMed and IndMed, websites of the WHO, and UNICEF. No restrictions were applied in terms of study designs. The primary outcome measure was congenital rubella syndrome (CRS) which was further categorized as suspected CRS and confirmed CRS as defined by World Health Organization (WHO).

Comprehensive evidence about the true burden of CRS in India is not available. Almost all studies have been done in nstitutional/hospital set-ups and community-based studies are grossly lacking. There are no studies assessing the prevalence of CRS in general population. All studies have evaluated the CRS burden in symptomatic cohorts of children. 1-15% of all infants suspected to have intra-uterine infection were found to have laboratory evidence of CRS. About 3-10% of suspected CRS cases are ultimately proven to have confirmed CRS with the aid of laboratory tests. CRS accounts for 10-15% of pediatric cataract. 10-50% of children with congenital anomalies have laboratory evidence of CRS. 10-30% of adolescent females and 12-30% of women in the reproductive age-group are susceptible to rubella infection in India. RCVs are highly immunogenic in Indian adolescents and women. The coverage data of RCVs in India is not available. However, the coverage of MMR vaccine has been reported as 42%, 30% and 5% from Delhi, Chandigarh and Goa, respectively.

This systematic review identifies and explores factors associated with the prevalence of CRS in India. There is a need for urgent action in terms of revamping the national immunization policy and introduction of RCVs in the national immunization program. Active surveillance of rubella and CRS is needed to redress the burden of CRS in India.