Prevalence of HI antibody titer against rubella virus to determine the effect of mass vaccination in Tehran

Systematic Review of Measles and Rubella Serology Studies

Serological tests provide information about individual immunity from historical infection or immunization. Cross-sectional serological studies provide data about the age- and sex-specific immunity levels for individuals in the studied population, and these data can provide a point of comparison for the results of transmission models. In the context of developing an integrated model for measles and rubella transmission, we reviewed the existing measles and rubella literature to identify the results of national serological studies that provided cross-sectional estimates of population immunity at the time of data collection. We systematically searched PubMed, the Science Citation Index, and references we identified from relevant articles published in English. We extracted serological data for comparison to transmission model outputs. For rubella, serological studies of women of child-bearing age provide information about the potential risks of infants born with congenital rubella syndrome. Serological studies also document the loss of maternal antibodies, which occurs at different rates for the different viruses and according to the nature of the induced immunity (i.e., infection or vaccine). The serological evidence remains limited for some areas, with studies from developed countries representing a disproportionate part of the evidence. The collection and review of serological evidence can help program managers identify immunity gaps in the population, which may help them better understand the characteristics of individuals within their populations who may participate in transmission and manage risks.

Seroepidemiology of Rubella in Women Under 25 Years Old Attending Medical Centers in Ahvaz, Iran in 2013

Background:

Rubella is a mild viral infection affecting women of reproductive age, and the fetus in early pregnancy, leading to miscarriage, stillbirth and Congenital Rubella Syndrome.

Objectives:

The present study aimed to assess serum level of anti-rubella antibodies in women younger than 25 years attending medical centers in Ahvaz city.

Patients and Methods:

This descriptive cross-sectional study was conducted on 760 women younger than 25 years attending medical centers in Ahvaz. A sample of 3 mL of venous blood was taken from each woman and ELISA method was used to assess anti-rubella IgG levels. Antibody level more than 11 IU/mL was considered safe. Data was analyzed by SPSS software using Chi-square, ANOVA and Pearson Correlation tests.

Results:

Of total samples, 683 women (88.9%) had immunity against rubella, 80 (10.4%) no immunity and 5 (0.7%) intermediate levels of antibody. Immunity to rubella increased significantly with aging (P = 0.001) and a significant association was found between age and antibody titer (P = 0.001, r = 0.261).

Conclusions:

More than 95% of 15 to 25 year-old women (main reproductive age in Iran) are within acceptable immunity range. Level of immunity to rubella in women of reproductive age in this region appears satisfactory.

Rubella seroprevalence among primary and pre- primary school pupils at Moi's Bridge location, Uasin Gishu District, Kenya

BACKGROUND

Rubella is an infectious and generally mild childhood viral disease. The disease is of public health importance because infection acquired during early pregnancy often results in foetal abnormalities that are classified as congenital rubella syndrome (CRS). The burden of rubella infection in most developing countries in not well documented because of limited epidemiological data. However, availability of an effective vaccine has made it necessary to have all the countries with no routine vaccination schedule to evaluate the burden of disease in order to make informed decisions on rubella vaccination and strategy. To address this gap we conducted a study to determine age-specific rubella seroprevalence rates and related risk factors among primary and pre-primary school children in Uasin Gishu district, Moi's Bridge location of Kenya.

METHODS

Subjects of the study were 498 pupils from seven primary schools aged 4-20 years. Questionnaire surveys with blood sampling were conducted between January to July 2005. Samples were tested for rubella specific IgG antibody using ELISA test kit (Enzygnost Behring, Germany).

RESULTS

Overall, rubella seropositivity rate was 80% and it increased with age from 59% (among ages 4-6 years) to 94% (ages 14-20 years). Multivariate logistic regression analysis model, showed that age of child and ownership of a television set which is a proxy measure of socio-economic status of family were significantly associated with rubella seropositivity. The odds of rubella seropositivity in a child older than 13 years was more than that in children younger than 7 years (OR = 3.8 95% CI 2.56-5.78). The odds of rubella seropositivity in a child whose family did not own a television set was 3 times higher than that of child whose family owned a set (OR 3.06, 95% CI 1.17-7.97).

CONCLUSION

The study provides important and highly useful information on rubella age specific seroprevalence rates in Kenya. Advancing age was found to be associated with increased risk of rubella. Low socio-economic factors suggest an increased risk of infection in certain categories of society, and control measures need to target this. Overall, the findings can also be used by policy makers to model introduction of routine rubella vaccination in the country and also other developing countries facing similar challenges. More than half of the children got infected in pre-primary and efforts to control rubella should target pre-school children. These data provides pre-vaccination information that can be used to guide immunization strategy as well as to determine success of an immunization programme.

Congenital rubella syndrome after rubella vaccination in 1-4 weeks periconceptional period

OBJECTIVE

To examine weather exposure to rubella vaccine during 1-4 wk periconceptional period can cause congenital rubella syndrome (CRS).

METHODS

This prospective study was performed in 60 pregnant women who received rubella vaccine inadvertently 1-4 wk pre or post conception. Time of conception was determined by last menstrual period (LMP) and first trimester sonography. In addition to gathering mother's obstetric and demographic information, all neonates were evaluated for CRS signs by systemic physical examination and anti rubella IgG and IgM antibody titers in cord blood samples.

RESULTS

A total of 60 pregnant women with the median gestational age of 38 weeks were studied. The mean maternal age was 22 years and 58.3% of pregnancies were unintended. In 90% of mothers there were no post vaccination side effects (fever, lymphadenopathy, arthritis, arthralgia). None of the mothers had a history of drug abuse, smoking or teratogenic exposures. Mean neonatal weight was 3100grs and 6.7% of them were premature. No signs of CRS were found in the neonates based on systemic physical exam at birth and one month later. Mean value of cord blood anti rubella IgG titere was 148/28+/-67/26 lu/ml. cord blood anti rubella IgM was negative in all of the neonates.

CONCLUSION

In this study inadvertent rubella vaccination 1-4 wk before and after conception did not cause CRS in neonates and according to all reasearches pregnancy termination is not indicated in these cases.