Study of the teratogenicity of the vaccine strain of the Rubella virus «Orlov-V¼ (Matonaviridae: Rubivirus: Rubella virus) in experience on rhesus macaques.

INTRODUCTION: Rubella virus has pronounced teratogenic properties that can cause generalized and persistent intrauterine infection of the fetus. As a result, the control of the loss of teratogenicity inherent in «wild-type¼ virus strains is a necessary stage of a preclinical study of the vaccine strain for a live attenuated rubella vaccine.The purpose of the study is to comprehensively study the teratogenic properties of the vaccine strain of rubella virus «Orlov-V¼ in the experiment on rhesus macaques. MATERIAL AND METHODS: Seronegative to rubella virus female rhesus macaques in early pregnancy at the age of 4-7 years (n = 13) were used in the experiment. Animals of the experimental group (n = 9) received single immunization intramuscularly with a preparation from the «Orlov-V¼ strain. The control group of the monkeys (n = 3) were immunized with a commercial vaccine containing Wistar RA27/3 strain. The female of the control group (n = 1) was injected with a solvent used in the rubella vaccine. Study of possible teratogenic properties of vaccine strains of rubella virus was carried out using a complex of clinical, immunological, pathomorphological and virological methods. Clinical observations were made within 3 months after the monkeys' birth. Determination of antibody titers in the blood serum of immunized monkeys was performed in HI test on the 28th-30th day after infection. The ELISA method was applied to determine IgM antibodies in the blood serum of newborns within the first month of life. Detection of rubella virus RNA was performed by PCR with electrophoretic detection of amplicons. RESULTS: No markers of congenital rubella infection were found in infants born from monkeys vaccinated during the pregnancy. It is shown that PCR can be an informative method to confirm the absence of teratogenic properties of vaccine strains of rubella virus. DISCUSSION: The obtained data demonstrated that vaccine strains of the «Orlov-V¼ rubella virus and Wistar RA27/3 have lost their teratogenic properties. The possibility of using an alternative strategy for preclinical assessment of specific safety of antiviral vaccines including a complex of clinical, immunological, pathologic and virological methods instead of the classical pathologic method is discussed. CONCLUSION: The results obtained in this study showed the absence of teratogenic properties and high immunogenic activity of the vaccine strain of rubella virus «Orlov-V¼.

The Capsid Protein of Rubella Virus Antagonizes RNA Interference in Mammalian Cells.

Rubella virus (RuV) is the infectious agent of a series of birth defect diseases termed congenital rubella syndrome, which is a major public health concern all around the world. RNA interference (RNAi) is a crucial antiviral defense mechanism in eukaryotes, and numerous viruses have been found to encode viral suppressors of RNAi (VSRs) to evade antiviral RNAi response. However, there is little knowledge about whether and how RuV antagonizes RNAi. In this study, we identified that the RuV capsid protein is a potent VSR that can efficiently suppress shRNA- and siRNA-induced RNAi in mammalian cells. Moreover, the VSR activity of the RuV capsid is dependent on its dimerization and double-stranded RNA (dsRNA)-binding activity. In addition, ectopic expression of the RuV capsid can effectively rescue the replication defect of a VSR-deficient virus or replicon, implying that the RuV capsid can act as a VSR in the context of viral infection. Together, our findings uncover that RuV encodes a VSR to evade antiviral RNAi response, which expands our understanding of RuV-host interaction and sheds light on the potential therapeutic target against RuV.

Epidemiology of acute rubella infection in Zambia during the pre-vaccination period (2005-2016) as a baseline for monitoring rubella epidemiology in the post-rubella vaccine introduction era.

BACKGROUND: Rubella is highly under reported in Zambia as in most sub-Saharan countries despite being a disease of major public health concern especially among women of childbearing age. In September 2016, Zambia introduced a combined measles-rubella vaccine in children 0-14 years. In this study, we estimated the proportion positive for acute rubella among suspected but negative measles cases between 2005 and 2016 and determined its correlates for monitoring rubella epidemiology post-rubella vaccine introduction. METHODS: In a retrospective study, 4497 measles IgM negative serum samples from 5686 clinically suspected measles cases were examined for rubella IgM antibodies using the Siemens, Enzygnost® ELISA kit at the national measles laboratory. Data on demographics, year and month of onset were extracted from the surveillance data. Multivariate logistic regression analysis using backward variable selection was conducted to determine independent predictors for acute rubella. The magnitude of association was estimated using adjusted odds ratio with a 95% confidence interval. RESULTS: Overall, a proportion of 29.2% (1313/4497) affecting mostly those between 5 and 24 years was determined. Only age, province, month and year were independently associated with acute rubella. The regional proportions varied from 21.8-37.3% peaking in the month of October. Persons in the age group 10-14 years (Adjusted Odds Ratio [AOR] = 2.43; 95% CI [2.01-2.95]) were more likely while those aged < 1 year less likely (AOR = 0.31; 95% CI [021-0.48]) to have acute rubella compared to those aged 25 years or older. Persons in 2010 were less likely (AOR = 0.12; CI [0.05, 0.28]) to have acute rubella compared to those in 2016. While acute rubella was more likely to occur between July and November compared to December, it was less likely to occur between February and May. CONCLUSIONS: Rubella virus was circulating in Zambia between 2005 and 2016 affecting mostly persons in the age group 5-24 years peaking in the hot dry season month of October. Although vaccination against rubella has been launched, these baseline data are important to provide a reference point when determining the impact of the vaccination program implemented.

Teratogenic Rubella Virus Alters the Endodermal Differentiation Capacity of Human Induced Pluripotent Stem Cells.

The study of congenital virus infections in humans requires suitable ex vivo platforms for the species-specific events during embryonal development. A prominent example for these infections is rubella virus (RV) which most commonly leads to defects in ear, heart, and eye development. We applied teratogenic RV to human induced pluripotent stem cells (iPSCs) followed by differentiation into cells of the three embryonic lineages (ecto-, meso-, and endoderm) as a cell culture model for blastocyst- and gastrulation-like stages. In the presence of RV, lineage-specific differentiation markers were expressed, indicating that lineage identity was maintained. However, portrait analysis of the transcriptomic expression signatures of all samples revealed that mock- and RV-infected endodermal cells were less related to each other than their ecto- and mesodermal counterparts. Markers for definitive endoderm were increased during RV infection. Profound alterations of the epigenetic landscape including the expression level of components of the chromatin remodeling complexes and an induction of type III interferons were found, especially after endodermal differentiation of RV-infected iPSCs. Moreover, the eye field transcription factors RAX and SIX3 and components of the gene set vasculogenesis were identified as dysregulated transcripts. Although iPSC morphology was maintained, the formation of embryoid bodies as three-dimensional cell aggregates and as such cellular adhesion capacity was impaired during RV infection. The correlation of the molecular alterations induced by RV during differentiation of iPSCs with the clinical signs of congenital rubella syndrome suggests mechanisms of viral impairment of human development.

Long-term immunogenicity of measles, mumps and rubella-containing vaccines in healthy young children: A 10-year follow-up.

Measles and mumps outbreaks still occur in countries that have successfully implemented universal routine immunization programs. Measles outbreaks are mostly associated to absent or incomplete vaccination, whereas for mumps outbreaks the combined effects of waning of immunity and circulating new strains are incriminated. It is therefore increasingly useful to characterize the long-lasting immunity induced by measles-, mumps, and rubella (MMR)-containing vaccines. In this 10-year study, 1887 healthy children aged 12-22 months, randomized to receive 1 or 2 doses of MMR-containing vaccines (Priorix or Priorix-Tetra; GSK), were included in an antibody persistence analysis. A total of 364 children in the 1-dose group received a second dose out of study according to their local vaccination schedule between Years 4 and 10 post-dose 1, and were included in a separate post-hoc analysis to evaluate the effect of the second dose when given later. Anti-measles, -mumps and -rubella antibody titers were measured by commercial ELISA kits (Enzygnost, Siemens) after each vaccine dose and at Years 1, 2, 4, 6, 8 and 10 post-vaccination. Antibodies against measles and rubella declined moderately after vaccination but remained well above the seropositivity threshold after 10 years. The anti-measles antibody titers elicited by Priorix-Tetra remained about 2-fold higher throughout the study as compared with Priorix. A second dose of MMR vaccine later in life had a minor and transient effect on anti-measles and anti-rubella waning titers. In contrast, anti-mumps antibody levels remained relatively stable over the 10-year follow-up and a second dose of MMR vaccine, given anytime over the 10-year period, had a boosting effect on anti-mumps antibody titers and seropositivity rates. In conclusion, 1 or 2 doses of MMR-containing vaccines given to children in their second year of life induced antibody responses against measles, mumps and rubella viruses that persisted at least up to 10 years post-vaccination. Clinical trial registration number: NCT00226499.

Seroprevalence of measles, mumps & rubella antibodies among 5-10 years old children in north India.

Background & objectives: : Globally, there is an effort to eliminate the measles and control rubella as these diseases lead to considerable morbidity and mortality especially among under-five children and are important public health problems. This study was aimed to estimate the seroprevalence of measles, mumps and rubella (MMR) antibodies among children of age 5-10 yr in Chandigarh, north India, to provide evidence on prevalent immunity levels. Methods: : This cross-sectional study was conducted in Chandigarh, among 196 randomly selected healthy children (5-10 yr), who received either one or two doses of measles or MMR combination vaccine. Socio-economic background and immunization history were recorded. Blood sample (2 ml) was collected to estimate the MMR IgG antibody titres by using ELISA kits. Results: : Protective seroprevalence of MMR antibodies was 40.8, 75.5 and 86.2 per cent, respectively. The geometric mean titres of MMR IgG antibodies in the study children were 11.3, 50.6 and 54.3 international units (IU)/ ml, respectively. The proportion of seroprotected children for measles was significantly higher among those who had received two or more doses (46.4%) of measles vaccine compared to those who had received single dose (35.6%) (P <0.001). About 16 per cent of children had received single dose of MMR vaccine. Among these, 71.4 and 100 per cent were seroprotected against mumps and rubella, respectively. Interpretation & conclusions: : A large proportion of children aged 5-10 yr lacked protective immunity against measles (60%); about one-fourth (15-25%) were susceptible to infection with mumps and rubella virus. Mumps vaccination may be considered to be included in National Immunization Schedule for children with periodic serosurveillance.

Battery Powered Portable Thermal Cycler for Continuous-Flow Polymerase Chain Reaction Diagnosis by Single Thermostatic Thermoelectric Cooler and Open-Loop Controller.

Temperature control is the most important and fundamental part of a polymerase chain reaction (PCR). To date, there have been several methods to realize the periodic heating and cooling of the thermal-cycler system for continuous-flow PCR reactions, and three of them were widely used: the thermo-cycled thermoelectric cooler (TEC), the heating block, and the thermostatic heater. In the present study, a new approach called open-loop controlled single thermostatic TEC was introduced to control the thermal cycle during the amplification process. Differing from the former three methods, the size of this microdevice is much smaller, especially when compared to the microdevice used in the heating block method. Furthermore, the rising and cooling speed of this method is much rapider than that in a traditional TEC cycler, and is nearly 20-30% faster than a single thermostatic heater. Thus, a portable PCR system was made without any external heat source, and only a Teflon tube-wrapped TEC chip was used to achieve the continuous-flow PCR reactions. This provides an efficient way to reduce the size of the system and simplify it. In addition, through further experiments, the microdevice is not only found to be capable of amplification of a PCR product from Human papillomavirus type 49 (Genbank ref: X74480.1) and Rubella virus (RUBV), but also enables clinical diagnostics, such as a test for hepatitis B virus.

Rubella Virus-Associated Cutaneous Granulomatous Disease: a Unique Complication in Immune-Deficient Patients, Not Limited to DNA Repair Disorders.

The association of immunodeficiency-related vaccine-derived rubella virus (iVDRV) with cutaneous and visceral granulomatous disease has been reported in patients with primary immunodeficiency disorders (PIDs). The majority of these PID patients with rubella-positive granulomas had DNA repair disorders. To support this line of inquiry, we provide additional descriptive data on seven previously reported patients with Nijmegen breakage syndrome (NBS) (n = 3) and ataxia telangiectasia (AT) (n = 4) as well as eight previously unreported patients with iVDRV-induced cutaneous granulomas and DNA repair disorders including NBS (n = 1), AT (n = 5), DNA ligase 4 deficiency (n = 1), and Artemis deficiency (n = 1). We also provide descriptive data on several previously unreported PID patients with iVDRV-induced cutaneous granulomas including cartilage hair hypoplasia (n = 1), warts, hypogammaglobulinemia, immunodeficiency, myelokathexis (WHIM) syndrome (n = 1), MHC class II deficiency (n = 1), Coronin-1A deficiency (n = 1), X-linked severe combined immunodeficiency (X-SCID) (n = 1), and combined immunodeficiency without a molecular diagnosis (n = 1). At the time of this report, the median age of the patients with skin granulomas and DNA repair disorders was 9 years (range 3-18). Cutaneous granulomas have been documented in all, while visceral granulomas were observed in six cases (40%). All patients had received rubella virus vaccine. The median duration of time elapsed from vaccination to the development of cutaneous granulomas was 48 months (range 2-152). Hematopoietic cell transplantation was reported to result in scarring resolution of cutaneous granulomas in two patients with NBS, one patient with AT, one patient with Artemis deficiency, one patient with DNA Ligase 4 deficiency, one patient with MHC class II deficiency, and one patient with combined immunodeficiency without a known molecular etiology. Of the previously reported and unreported cases, the majority share the diagnosis of a DNA repair disorder. Analysis of additional patients with this complication may clarify determinants of rubella pathogenesis, identify specific immune defects resulting in chronic infection, and may lead to defect-specific therapies.

Immunopathology of Virus-Induced Anterior Uveitis.

Herpes simplex virus, varicella zoster virus, human cytomegalovirus, and rubella virus are the most common causes of virus-induced anterior uveitis. They can present in a variety of entities not only with typical but also overlapping clinical characteristics. These viral infections are commonly associated with ocular infiltration of T cells and B/plasma cells, and expression of cytokines and chemokines typical of a proinflammatory immune response. The infections differ in that the herpes viruses cause an acute lytic infection and inflammation, whereas rubella virus is a chronic low-grade infection with slowly progressing immunopathological responses. The outcome of an intraocular viral infection may largely be guided by the characteristics of the virus, which subsequently dictates the severity and type of the immune response, and the host immune status.

The pathogenesis of microcephaly resulting from congenital infections: why is my baby's head so small?

The emergence of Zika-virus-associated congenital microcephaly has engendered renewed interest in the pathogenesis of microcephaly induced by infectious agents. Three of the original "TORCH" agents are associated with an appreciable incidence of congenital microcephaly: cytomegalovirus, rubella virus, and Toxoplasma gondii. The pathology of congenital microcephaly is characterized by neurotropic infectious agents that involve the fetal nervous system, leading to brain destruction with calcifications, microcephaly, sensorineural hearing loss, and ophthalmologic abnormalities. The inflammatory reaction induced by these four agents has an important role in pathogenesis. The potential role of "strain differences" in pathogenesis of microcephaly by these four pathogens is examined. Specific epidemiologic factors, such as first and early second trimester maternal infection, and the manifestations of congenital infection in the infant, shed some light on the pathogenesis. Immune aspects of normal pregnancy and their role in congenital infections is examined. In this review, we integrate all these findings to create a unified hypothesis of the pathogenesis of congenital microcephaly induced by these infectious agents.

Infection of iPSC Lines with Miscarriage-Associated Coxsackievirus and Measles Virus and Teratogenic Rubella Virus as a Model for Viral Impairment of Early Human Embryogenesis.

Human induced pluripotent stem cell (iPSC) lines are a promising model for the early phase of human embryonic development. Here, their contribution to the still incompletely understood pathogenesis of congenital virus infections was evaluated. The infection of iPSC lines with miscarriage-associated coxsackievirus B3 (CVB3) and measles virus (MV) was compared to the efficient teratogen rubella virus (RV). While CVB3 and MV were found to be cytopathogenic on iPSC lines, RV replicated without impairment of iPSC colony morphology and integrity. This so far outstanding course of infection enabled maintenance of RV-infected iPSC cultures over several passages and their subsequent differentiation to ectoderm, endoderm, and mesoderm. A modification of the metabolic profile of infected iPSC lines was the only common aspect for all three viruses. This study points toward two important aspects. First, iPSC lines represent a suitable cell culture model for early embryonic virus infection. Second, metabolic activity represents an important means for evaluation of pathogen-associated alterations in iPSC lines.

Vaccination in secondary school students expedites rubella control and prevents congenital rubella syndrome.

BACKGROUND: In order to control the spread of rubella and reduce the risk for congenital rubella syndrome, an additional rubella vaccination program was set up for all secondary school students since 2008 in Zhejiang, China. METHODS: We conducted a descriptive analysis of rubella incidence among different age groups from 2005 to 2015 and a serosurvey of female subjects aged 15-39 years to understand the possible effects of this immunization program. RESULTS: The average annual rubella incidence rate had decreased from 15.86 per 100,000 population (2005-2007) to 0.75 per 100,000 population (2013-2015) in Zhejiang. The decrease in the rate of rubella incidence in girls aged 15-19 years was more accelerated (from 138.30 to 0.34 per 100,000) than in the total population during 2008-2015 (from 32.20 to 0.46 per 100,000). Of 1225 female subjects in the serosurvey, 256 (20.9%) were not immune to rubella. The proportion of subjects immune to rubella was significantly different among different age groups (Wald χ2 = 22.19, p = 0.000), and subjects aged 15-19 years old had the highest immunity (88.0%). Rubella antibody levels were significantly lower in women aged 25-30 years with 26.7% of them not immune, followed by the group aged 20-24 years (25.0%) and 30-35 years (24.5%). CONCLUSIONS: Rubella vaccine included in the Expanded Program on Immunization together with vaccination activities for secondary school students can help in rubella control, particularly in targeted age groups in the program. Seroprevalence of antibodies to the rubella virus amongst the female population within childbearing age in Zhejiang, China, is still too low to provide immunity. In addition to vaccination programs in the secondary schools, rubella vaccination should also be encouraged in women of childbearing age, which can be done effectively combined with pre-marital examination in China.

Illuminating uveitis: metagenomic deep sequencing identifies common and rare pathogens.

BACKGROUND: Ocular infections remain a major cause of blindness and morbidity worldwide. While prognosis is dependent on the timing and accuracy of diagnosis, the etiology remains elusive in ~50 % of presumed infectious uveitis cases. The objective of this study is to determine if unbiased metagenomic deep sequencing (MDS) can accurately detect pathogens in intraocular fluid samples of patients with uveitis. METHODS: This is a proof-of-concept study, in which intraocular fluid samples were obtained from five subjects with known diagnoses, and one subject with bilateral chronic uveitis without a known etiology. Samples were subjected to MDS, and results were compared with those from conventional diagnostic tests. Pathogens were identified using a rapid computational pipeline to analyze the non-host sequences obtained from MDS. RESULTS: Unbiased MDS of intraocular fluid produced results concordant with known diagnoses in subjects with (n = 4) and without (n = 1) uveitis. Samples positive for Cryptococcus neoformans, Toxoplasma gondii, and herpes simplex virus 1 as tested by a Clinical Laboratory Improvement Amendments-certified laboratory were correctly identified with MDS. Rubella virus was identified in one case of chronic bilateral idiopathic uveitis. The subject's strain was most closely related to a German rubella virus strain isolated in 1992, one year before he developed a fever and rash while living in Germany. The pattern and the number of viral identified mutations present in the patient's strain were consistent with long-term viral replication in the eye. CONCLUSIONS: MDS can identify fungi, parasites, and DNA and RNA viruses in minute volumes of intraocular fluid samples. The identification of chronic intraocular rubella virus infection highlights the eye's role as a long-term pathogen reservoir, which has implications for virus eradication and emerging global epidemics.

Measles & rubella outbreaks in Maharashtra State, India.

BACKGROUND & OBJECTIVES: Under the outbreak-based measles surveillance in Maharashtra State the National Institute of Virology at Pune receives 3-5 serum samples from each outbreak and samples from the local hospitals in Pune for laboratory diagnosis. This report describes one year data on the measles and rubella serology, virus isolation and genotyping. METHODS: Maharashtra State Health Agencies investigated 98 suspected outbreaks between January-December 2013 in the 20 districts. Altogether, 491 serum samples were received from 20 districts and 126 suspected cases from local hospitals. Samples were tested for the measles and rubella IgM antibodies by commercial enzyme immunoassay (EIA). To understand the diagnostic utility, a subset of serum samples (n=53) was tested by measles focus reduction neutralization test (FRNT). Further, 37 throat swabs and 32 urine specimens were tested by measles reverse transcription (RT)-PCR and positive products were sequenced. Virus isolation was performed in Vero hSLAM cells. RESULTS: Of the 98 suspected measles outbreaks, 61 were confirmed as measles, 12 as rubella and 21 confirmed as the mixed outbreaks. Four outbreaks remained unconfirmed. Of the 126 cases from the local hospitals, 91 were confirmed for measles and three for rubella. Overall, 93.6 per cent (383/409) confirmed measles cases were in the age group of 0-15 yr. Measles virus was detected in 18 of 38 specimens obtained from the suspected cases. Sequencing of PCR products revealed circulation of D4 (n=9) and D8 (n=9) strains. Four measles viruses (three D4 & one D8) were isolated. INTERPRETATION & CONCLUSIONS: Altogether, 94 measles and rubella outbreaks were confirmed in 2013 in the State of Maharasthra indicating the necessity to increase measles vaccine coverage in the State.

Well begun is half done: Rubella virus perturbs autophagy signaling, thereby facilitating the construction of viral replication compartments.

The rubella virus is the causative agent of postnatal German measles and the congenital rubella syndrome. The majority of the rubella virus replication complexes originate from the endomembrane system. The rubella virus perturbs the signaling pathways regulating the formation of autophagic membranes in the infected cells, including the Ras/Raf/MEK/ERK and PI3K/Akt pathways. It is widely accepted that these pathways inhibit autophagy. In contrast, the class III PI3K enzymes are essential for autophagy initiation. By manipulating the Ras/Raf/MEK/ERK, class I PI3K/Akt and class III PI3K axes of signal transduction, the rubella virus may differentially regulate the autophagic cascade, with consequent stimulation of the initiation and strong suppression of the later phases. Dysregulation of autophagy by this virus can have a significant impact on the construction of replication compartments by regulating membrane trafficking. We hypothesize that the rubella virus perturbs the autophagic process in order to prevent the degradation of the virus progeny, and to ensure its replication by hijacking omegasomes for the construction of the replication complexes. The virus is therefore able to utilize an antiviral mechanism to its own advantage. Therapeutic modalities targeting the autophagic process may help to ameliorate the serious consequences of the congenital rubella syndrome.

[The very severe sensorineural deafness patients caused by rubella virus infection: two cases report].

To explore the audiological features in children who were sever sensorineural hearing loss infected with rubella virus. There were two cases of rubella virus infection in children who were deaf, they conducted the distortion product otoacoustic emission, ABR and auditory steady-state evoked response (ASSR) examination, then analyzed the results comprehensively. Two patients' mothers were prompted to have infected rubella virus during the early three months pregnant period by history and laboratory tests. The two patients were not detected deafness gene mutation. Audiology results implied the two patients were very severe binaural sensorineural deafness, so they were recommended to equipped with hearing aids and cochlear implant surgery. Early pregnancy women infected with rubella virus can cause very severe offspring sensorineural deafness. The crowd whose mother were suspected to infect with rubella virus in early pregnancy, that should be tracked and detected hearing in order to achieve early detection, early intervention and early treatment.

Multiphasic acute disseminated encephalomyelitis associated with atypical rubella virus infection.

We report the first case of an occurrence of multiphasic acute disseminated encephalomyelitis (ADEM) associated with atypical rubella virus infection with no rash and long-term increased titers of serum anti-rubella IgM in a 17-year-old male who had no history of rubella vaccination. He suffered from at least six clinical exacerbations with disseminated hyperintense lesions on FLAIR MR images during the course of 18 months. Repeated methylprednisolone pulse therapy and intravenous immunoglobulin therapy resolved the exacerbations. In patients with multiphasic ADEM of unknown etiology, clinicians should also consider the possibility of preceding infection with rubella virus.

[Epidemiologic control for rubella in pregnant women].

AIM: Evaluate effectiveness of measures specified by epidemiologic control for rubella in pregnant women. MATERIALS AND METHODS: 585 pregnant women with suspected measles were laboratory examined in 10 Regional Centers of Control for Measles and Rubella by EIA. RESULTS: 24 rubella infected pregnant women aged 16-36 years were detected among the examined pregnant women, most of those (91.7%) were either not immunized against rubella or had unknown immunization anamnesis: 16 women terminated pregnancy, in 8 women pregnancy ended with delivery at term. Of the 8 newborns only a single child had innate rubella infection (the child was clinically healthy). CONCLUSION: Epidemiologic investigation of each rubella case in pregnant women with obligatory laboratory examination of women and source of infection revealed a significant number of women at childbearing age susceptible to rubella virus that retains the possibility of birth of children with innate rubella syndrome.