Rubella, a contagious viral infection that is generally mild, most often affects children and young adults, except when it occurs during pregnancy [1]. Transmission is strictly interhuman (saliva droplets emitted by people infected during coughing or sneezing) and man is the only reservoir of the rubella virus. In pregnant women, mother-to-child transmission of the virus occurs through the placenta and can lead to rubella embryopathy. Rubella virus infection is particularly severe in primary maternal infection during the first trimester of pregnancy [2]. The main manifestations are intrauterine stunting, abortion [3] [4] [5]. The severity of infection varies with the age of pregnancy [6]. Infection with these viruses is immunizing and pre-pregnancy contamination is in principle protective against these congenital risks [7]. The development of sero-diagnostic and vaccination methods is currently making it possible to confirm the diagnosis, to detect inappropriate infections and to judge the advisability of individual and collective vaccination. In the Central African Republic, although the combined measles, mumps and rubella (MMR) vaccine is recommended, its introduction is not yet effective in the country. It is in this context that we propose to evaluate the immune status of pregnant women towards rubella in order to have updated data for an effective prevention strategy.

Rubella infection during pregnancy can be the cause of embryopathy which is the consequence of a benign condition difficult to diagnose in its abortive or atypical forms without eruption and which are contagious. In our study, the majority of patients lived in urban areas with no difference between the areas. Indeed, geographic location is an important factor influencing the epidemiological variations and immune status of people infected with rubella, as already reported in some studies [7]. Indeed, the best social conditions were already reported by some authors as low risk factors for acquiring rubella [8]. During this work, pregnant women aged 20 to 24 years and those aged 25 to 29 years developed IgG antibody responses against the disease with a statistically different age range (p = 0.018). Our results corroborate those of some authors [9] [10] and may, however, be explained because the diagnosis of rubella is part of the

systematic prenatal assessment in pregnant women. However, 95.85% of pregnant women had IgG-negative serology and were therefore susceptible to the virus. In addition, 4.15% of our subjects were at risk of contracting the infection during pregnancy. These same findings were already made by some authors in Kenya who reported a 7% risk of primary infection in pregnant women [10]. This is likely due to the lack of vaccination coverage for rubella in the country [11]. This primary infection could give these pregnant women protective immunity but can be serious for the fetus with risk of rubella embryopathy [12]. This would imply that the spread of the virus would regress without disappearing in these women because of the persistent antibody titres that consolidate immunity against this disease. This persistence of the virus maintains a level of immunity that would prevent an outbreak. However, it would be wise to monitor the level of community protection through serological surveys. In addition, at the individual level it will be useful to seek immunity in all girls of reproductive age in order to eliminate any risk of rubella embryopathy. However, it would be wise to explore several successive serologies and assess for women with positive IgM serology the stage of pregnancy that has an impact on the risk of transmission to the fetus. Since these data are not available at the time of the study, this constitutes a limit to this work.

Rubella infection remains particularly serious when it occurs during pregnancy. Patients aged 20 - 24 and those aged 25 - 29 had a rubella profile suggesting persistent infection. Thus, it would be advisable to monitor the degree of protection of the community and to seek immunity in all girls of childbearing age in order to eliminate any risk of rubella embryopathy by setting up a specific prevention program.

WSN conceived, designed, conducted the experiments, analyzed the data and prepared the manuscript. JON read and approved the final manuscript. GA collected the data and REKL read and approved the final manuscript.

No funding received.

This study protocol received full approval from the local Ethics committee of Health Science Faculty of University of Bangui and was conducted in compliance with the declaration of Helsinki. Approval reference number 18/FACSS/CES/21.

Data is contained within the article.

The authors declare no conflicts of interest regarding the publication of this paper.

Nambei, W.S., Nguerenam-Ouefio, Jr., Gbamonza, A. and Kodia-Lenguetama, E.R. (2022) Rubella Immunity among Pregnant Women in Bangui, Central African Republic. Open Journal of Immunology, 12, 130-136. https://doi.org/10.4236/oji.2022.124009