Rubella outbreak in a Rural Kenyan District, 2014: documenting the need for routine rubella immunization in Kenya

Seroconversion and seroprevalence of TORCH infections in a pregnant women cohort study, Mombasa, Kenya, 2017-2019

Women infected during pregnancy with TORCH (Toxoplasmosis, Other, Rubella, Cytomegalovirus, and Herpes simplex viruses) pathogens have a higher risk of adverse birth outcomes including stillbirth / miscarriage because of mother-to-child transmission. To investigate these risks in pregnant women in Kenya, we analyzed serum specimens from a pregnancy cohort study at three healthcare facilities. A sample of 481 participants was selected for TORCH pathogen antibody testing to determine seroprevalence. A random selection of 285 from the 481 participants was selected to measure seroconversion. These sera were tested using an IgG enzyme-linked immunosorbent assay against 10 TORCH pathogens. We found that the seroprevalence of all but three of the 10 TORCH pathogens at enrollment was >30%, except for Bordetella pertussis (3.8%), Treponema pallidum (11.4%), and varicella zoster virus (0.5%). Conversely, very few participants seroconverted during their pregnancy and were herpes simplex virus type 2 (n = 24, 11.2%), parvovirus B19 (n = 14, 6.2%), and rubella (n = 12, 5.1%). For birth outcomes, 88% of the participant had live births and 12% had stillbirths or miscarriage. Cytomegalovirus positivity at enrolment had a statistically significant positive association with a live birth outcome (p = 0.0394). Of the 10 TORCH pathogens tested, none had an association with adverse pregnancy outcome.

Estimated incidence and transmission intensity of rubella infection in Zambia pre-vaccine era 2005-2016

The rubella disease burden in Zambia may be under-estimated. Using models, we describe the transmission dynamics, determine the incidence estimates and assess the level of underestimation of the real burden of rubella infection in Zambia during the pre-vaccination period 2005-2016. This study used both the deterministic compartmental model and likelihood-based method using a Bayesian framework to describe the epidemiology of rubella. A total of 1313 cases of rubella were confirmed with the highest annual number of 255 new cases recorded in 2008. However, 2014 recorded the highest monthly median positivity rate of 9.0%. The observed median rubella cases were 5.5. There was a seasonal pattern in the occurrence of laboratory-confirmed rubella, with higher test positivity rates of rubella infection usually recorded in the months of September, October and November. The modelled monthly median incidence of rubella infection among the general population was 76 and 20 among pregnant women. The incidence of rubella among the non-pregnant women was 44. The average effective reproductive number (Rt) between 2005 and 2016 was estimated as 1.2 with the peak of infection occurring in 2016. The measles surveillance system underestimates the observed burden of rubella. A mass vaccination campaign conducted between January and July is recommended.

Rubella seroprevalence using residual samples from the South African measles surveillance program: a cross-sectional analytic study

Introduction: South Africa is yet to introduce rubella-containing vaccines (RCV) into its routine immunization schedule. Selecting the target population when introducing RCV should take into account the ages of susceptible individuals in the population. We aimed to determine the seroprevalence of antibodies to rubella and characterize immunity gaps among individuals of all ages in South Africa. Methods: We tested for rubella immunoglobulin G (IgG) antibodies with a commercial enzyme-linked immunosorbent assay. We used residual samples collected from 2016 through 2018 as part of the national measles surveillance program. We only tested samples that were negative for measles and rubella immunoglobulin M (IgM) and explored the association between rubella susceptibility (IgG negative) and predictor variables (year of sample collection, age, sex, and province of residence) using logistic regression analysis. Results: We obtained results for 6057 records. Rubella susceptibility was highest among Individuals aged zero to 11 months (81.9%), followed by children 1 to 5 years old (71.5%), 6 to 10 y old (40.9%) and 11 to 15 y old (31.25) while the smallest proportion of susceptible individuals was among those 16 to 49 y old (19.9%). Females were less likely to be susceptible to rubella compared to males (OR = 0.79 (95%CI: 0.71-0.87), P < .001) in unadjusted analysis but this effect was not observed after adjusting for age and province. In multivariable logistic regression, age (OR = 6.24 (4.52-8.63), P < .001) and province of residence (OR = 0.97 (95%CI: 0.95-0.99), P = .01) were associated with rubella susceptibility. Conclusion: In the absence of rubella vaccination in the Expanded Program on Immunization in South Africa, the bulk of individuals susceptible to rubella are children under 16 y old. About 20% of individuals 16 to 49 y old are susceptible to rubella. This susceptibility gap must be born in mind during RCV introduction.

Rubella IgM epidemiology in the pre-rubella vaccination era in Uganda

Background

Control of Rubella and Congenital Rubella Syndrome using vaccination has shown great success in the America’s. Uganda is due to introduce the Rubella vaccine however the magnitude of transmission is not well documented. Therefore this study was done to determine IgM sero-prevalance for Rubella in order to help monitor vaccine effectiveness post introduction of the vaccine in routine vaccination programme.

Methods

A retrospective review of suspected measles cases data for the reporting period January 2007 to December 2016 in Uganda was Done. rubella IgM testing was done on 15,296 of the cases and the data was analyzed using STATA version 13.

Results

In total 15,296 cases were tested and 4255 (27.8%) tested positive and among females aged 15-49 years 88 out of 322 (27%) tested positive. The age distribution range was 0–80 years, rubella IgM positivity was reported in all the 15 regions of Uganda and throughout the ten year period in every month. Age group 5–15 years had OR 2.5 p-value < 0.001 of being rubella IgM positive compared to age < 5 years and testing measles IgM negative OR 6.3 p-value < 0.001.

Conclusion

Rubella is endemic in Uganda and although rubella IgM positivity is highest in the age 5-15 years even the younger, older and women of reprodutive age are affected. This means the risk of Congenital Rubella Syndrome is high hence the need to introduce the rubella vaccine for infants and pregnant mothers and continued surveillance to enhance its control.

Assessment of Economic Burden of Concurrent Measles and Rubella Outbreaks, Romania, 2011-2012

We estimated the economic impact of concurrent measles and rubella outbreaks in Romania during 2011–2012. We collected costs from surveys of 428 case-patients and caretakers, government records, and health staff interviews. We then estimated financial and opportunity costs. During the study period, 12,427 measles cases and 24,627 rubella cases were recorded; 27 infants had congenital rubella syndrome (CRS). The cost of the outbreaks was US $9.9 million. Cost per case was US $439 for measles, US $132 for rubella, and US $44,051 for CRS. Up to 36% of households needed to borrow money to pay for illness treatment. Approximately 17% of patients continued to work while ill to pay their treatment expenses. Our key study findings were that households incurred a high economic burden compared with their incomes, the health sector bore most costs, and CRS costs were substantial and relevant to include in rubella outbreak cost studies.

Risk Factors for Rubella Transmission in Kuyu District, Ethiopia, 2018: A Case-Control Study

Background

Rubella is a vaccine-preventable disease associated with a significant morbidity and adverse pregnancy outcomes, mainly if acquired in the first trimester of pregnancy with serious consequences to the fetus. Despite increased episodes of rubella epidemics (127 outbreaks in 2009–2015), rubella national vaccination is not yet introduced in Ethiopia. In January 2018, an increase of fever and rash cases was reported in Kuyu District of Oromia. We investigated the outbreak to confirm rubella, determine risk factors, and guide interventions.

Methods

We identified rubella cases from health centers and conducted a case-control study (1 case : 2 controls) with 150 participants, from March 12 to 15, 2018. Cases were people who presented with fever and rash or laboratory-confirmed cases. Controls were age matched (<15 yrs) with neighbors selected purposively. We interviewed parents by a structured questionnaire and observed the housing condition. Variables include sex, age, vaccination status, family size, contact history, housing condition, and travel history. Simple logistic regression was used to select the candidate variable at a P value <0.25. We identified risk factors at P < 0.05 with AOR and 95% CI by multivariate logistic regression.

Results

We identified 50 cases (with no death), and out of them, seven (14%) were confirmed cases (rubella IgM positive). The mean age of the cases was 6 ± 3 years and of the controls was 8 ± 4 years. Family size >5 (AOR = 2.4; 95% CI: 1.5–4.11), not well-ventilated living room (AOR = 4.7; 95% CI: 3.43–8.12), history of contact with rash people (AOR = 2.2; 95% CI: 1.6 3.5), no history of diarrhea in the last 14 days (AOR = 0.8; 95% CI: 0.6–0.9), and no history of vitamin A supplementation (AOR = 2.9; 95% CI: 1.7–2.6) were significant factors for rubella infection.

Conclusions

We identified rubella outbreak in the rural area. Crowded living condition, large family size, not receiving vitamin A in the last 6 months, and contact with people with symptoms of rubella were factors that drove the outbreak, while not having diarrhea in the last 14 days was the protective factor. We recommended the introduction of rubella immunization national programs and advocated the policy on rubella vaccine and strengthening surveillance for congenital rubella syndrome and rubella.

Seroprevelence of rubella among children suspected of having measles in Gadarif Hospital, Eastern Sudan

While generally mild in children, rubella infection during pregnancy can lead to miscarriage, foetal death or congenital rubella syndrome. Rubella vaccination is not yet available as a part of routine immunisation in Sudan, and the burden of infection is unknown. Using the clinical case definition adopted by the World Health Organisation, a total of 123 children suspected of having of measles were enrolled in this study during January-December 2017 in Gadarif Hospital, Eastern Sudan. 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. Sera were analysed for IgM specific antibodies against measles virus and rubella virus using enzyme-linked immunosorbent assay. Among the total 123 children suspected to have measles, 92 (74.8%) children were positive for measles IgM antibodies. Of the 31 children who had measles IgM antibodies negative, 20 (16.3%) children were seropositive for rubella IgM antibodies. Implementation of a surveillance system will provide the improved estimates of rubella virus and estimated the burden of congenital rubella syndrome. Such information is necessary and it is an important step for future policy decisions for vaccine delivery strategies.

Rubella outbreak in the school children, Addis Ababa, Ethiopia: February-April 2018

BACKGROUND

Rubella is a vaccine-preventable contagious disease causing an estimated 100,000 children to be born with congenital rubella syndrome each year globally. Studies documented that 18 rubella outbreaks were occurred each year in Ethiopia. Yeka sub-city woreda 13 public health emergency management office reported two measles suspected cases on 8 February, 2018. We investigated this outbreak to identify its etiology, describe the outbreak and implement control measures.

METHODS

We described the outbreak using descriptive epidemiology. The study population was defined as students learning in the school where the outbreak occurred. Suspected rubella case was defined as student with generalized rash whereas confirmed case was suspected case tested positive for rubella IgM. Questionnaires, checklists and students record review were used to collect data. We searched for new cases in classes daily and excluded them from classes. The school environment was assessed and the outbreak was described in person and time.

RESULTS

We identified 58 cases (median age: 4.6 years; IQR: 4-5 years) with six of them rubella IgM positive and 52 epidemiologically linked. The outbreak began on 8 February 2018 having multiple intermittent peaks during its course reaching its highest peak at 2 April, 2018 and ended on 20 April, 2018. Index cases were reported from two classes; however, cases were occurred in 13/15(86.67%) of the classes during the entire outbreak. Fifty five percent (32/58) and 45/58(77.59%) of the cases were females and 3-5 years children, respectively. Overall attack rate was 58/531(4.05%). Attack rate was higher in females 32/252 (12.7%) than in males 26/279 (9.32%), and higher 45/275(16.36%) in 3-5 years than those in 5-8 years 13/256(5.08%) children. Case fatality ratio was zero. All cases were vaccinated against measles but unvaccinated against rubella.

CONCLUSIONS

Attack rate was higher in females than in males and higher in 3-5 years than 5-8 years children. We recommended establishing rubella surveillance system, conducting sero-prevalence of rubella among child bearing age females and establishing CRS surveillance among young infants to provide evidence-based information for RCV introduction. It was also recommended to develop a national rubella surveillance guideline which aid to exclude rubella cases from schools during outbreak.

The Impact of Recent Rubella Vaccine Introduction in 5 Countries in The African Region

The World Health Organization (WHO) recommends that countries introduce rubella containing vaccines (RCVs) to reduce rubella circulation and the occurrence of congenital rubella syndrome (CRS). As of June 2017, a total of 18 countries have already introduced or are in the process of introducing RCV in routine child vaccination programs. RCV introduction during 2013 - 2014 in five countries in the Region resulted in a reduction of rubella incidence of 48% to 96% in the post-introduction period as compared to the average incidence in the years before introduction. These results suggest that initial mass vaccination campaigns and introduction of RCVs in routine immunization programs result in significant reduction in rubella incidence and a reduced potential for the occurrence of CRS.

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

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 measles surveillance 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 28,284 serum/plasma samples were collected and tested for measles IgM antibody and 11,151 (39.4%) were found positive. A total of 17,066 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.