Inmunización en las Américas. Resumen 2021

Los países de las Américas, con apoyo de la Organización Panamericana de la Salud (OPS), han logrado avances notables al proporcionar a los niños y las niñas una protección general contra las enfermedades prevenibles mediante vacunación. Los niveles sostenidos de elevadas coberturas nacionales de vacunación, la erradicación de la poliomielitis, la interrupción de la transmisión endémica del virus del sarampión y las iniciativas más recientes en favor de la eliminación de la rubéola y el síndrome de rubéola congénita son hitos continentales de este progreso. En la actualidad, los países administran vacunas a grupos etarios distintos de los incluidos en los programas tradicionales de inmunización infantil. La introducción de la vacuna estacional contra la gripe en los adultos en riesgo; la vacunación de adolescentes y adultos, hombres y mujeres, para la eliminación de la rubéola, y la definición de la carga de enfermedad del cáncer cervicouterino son las actividades que apoyan la necesidad fundamental de efectuar una transición de los programas nacionales de inmunización infantil a programas de inmunización de la familia. Una de las funciones de la OPS en su apoyo a los países es difundir información que destaque el progreso de la Región y los desafíos que enfrenta. Con ese fin, publica varios documentos técnicos relacionados con la inmunización, tales como los boletines de inmunización, los módulos de capacitación en inmunización y la serie de guías prácticas sobre rubéola, sarampión, tétanos neonatal, poliomielitis, vacuna pentavalente y fiebre amarilla.

Rubella Eradication: Not Yet Accomplished, but Entirely Feasible.

Rubella virus is the most teratogenic virus known to science and is capable of causing large epidemics. The RA 27/3 rubella vaccine, usually combined with measles vaccine, has eliminated rubella and congenital rubella syndrome from much of the world, notably from the Western Hemisphere. Except in immunosuppressed individuals, it is remarkably safe. Together with rubella vaccine strains used in China and Japan, eradication of the rubella virus is possible, indeed more feasible than eradication of measles or mumps.

Assessment of immune status against measles, mumps, and rubella in young Kuwaitis: MMR vaccine efficacy.

Seroprevalence studies on measles, mumps, and rubella immunoglobulin G (IgG) antibodies after the implementation of the measles-mumps-rubella (MMR) vaccine are lacking in Kuwait. This study is an age-stratified serological study to assess the herd immunity to measles, mumps, and rubella among the young Kuwaiti population to evaluate the effectiveness of the MMR vaccine. IgG antibody titers to mumps, measles, and rubella were determined with commercial immune-assay in serum samples of 1000 Kuwaitis aged 5 to 20 years. The highest level of seropositivity was to measles (94.6%), which was significantly higher in females than in males. The highest seronegativity was for mumps (29%). The percentage of the young Kuwaiti population who were serologically positive for all the components of the MMR vaccine was 47%, and 2% of the individuals were without any protective antibodies to measles, mumps, and rubella. Females aged 5 to 10 years were best protected to rubella; however, seronegativity in 8.2% of 11- to 20-year-old females makes them vulnerable to rubella virus infection and congenital complications during pregnancy. The study provided insight into the effect of the MMR vaccine on seroprevalence of antibodies against measles, mumps, and rubella in Kuwait, which will contribute to the global knowledge base of vaccine coverage and help to inform elimination strategies. The findings strengthen the need for a third dose of MMR vaccine and catch-up campaigns for the young Kuwaiti population to increase vaccination coverage and prevent waning immunity, especially among those who received only one dose of the vaccine during childhood.

Descriptive epidemiology of rubella disease and associated virus strains in Uganda.

Rubella virus causes a mild disease; however, infection during the first trimester of pregnancy may lead to congenital rubella syndrome (CRS) in over 80% of affected pregnancies. Vaccination is recommended and has been shown to effectively reduce CRS incidence. Uganda plans to introduce routine rubella vaccination in 2019. The World Health Organization recommends assessing the disease burden and obtaining the baseline molecular virological data before vaccine introduction. Sera collected during case-based measles surveillance from January 2005 to July 2018 were tested for rubella immunoglobulin M (IgM) antibodies. Sera from confirmed rubella outbreaks from January 2012 to August 2017 were screened using real-time reverse-transcription polymerase chain reaction (RT-PCR); for positive samples, a region within the E1 glycoprotein coding region was amplified and sequenced. Of the 23 196 suspected measles cases serologically tested in parallel for measles and rubella, 5334 (23%) were rubella IgM-positive of which 2710 (50.8%) cases were females with 2609 (96.3%) below 15 years of age. Rubella IgM-positive cases were distributed throughout the country and the highest number was detected in April, August, and November. Eighteen (18%) of the 100 sera screened were real-time RT-PCR-positive of which eight (44.4%) were successfully sequenced and genotypes 1G and 2B were identified. This study reports on the seroprevalence and molecular epidemiology of rubella. Increased knowledge of former and current rubella viruses circulating in Uganda will enhance efforts to monitor the impact of vaccination as Uganda moves toward control and elimination of rubella and CRS.

Seroprevalence of measles, mumps, rubella, and varicella zoster virus antibodies among healthcare students: analysis of vaccine efficacy and cost-effectiveness.

OBJECTIVE: The aims of this study are to determine the seroprevalence for measles, mumps, rubella, and varicella zoster virus (VZV) in a cohort of nursing students, to evaluate vaccination response rates of nonimmune students, and to calculate the cost of vaccinating students based on seroprevalence screening. METHODS: A cross-sectional study was conducted August 2015-November 2016 among 326 healthy nursing students aged 14.1-18.1 years. Serum IgG antibodies were measured by ELISA. Results were analyzed by the Chi-square test; a p-value of < 0.05 was considered statistically significant. RESULTS: The number of seropositive participants (%) was 308 (94.5%) for rubella, 295 (90.5%) for VZV, 244 (74.9%) for measles, and 219 (67.2%) for mumps. A significant correlation was found between measles IgG and age. A relationship was also observed between VZV IgG and kindergarten attendance. Response rates to measles, rubella, VZV, and mumps vaccination were 96%, 92.3%, 87.5%, 78.8%, respectively. The total cost of vaccination after IgG screening was less than vaccination without screening. CONCLUSIONS: In this study, participants' immunity to measles and VZV was low. Prevaccination serological screening was cost-effectiveness method for preventing measles, mumps, rubella, and varicella infections. We believe that administering booster measles, mumps, and rubella (MMR) vaccine doses or developing a special MMR vaccination strategy for at-risk groups may prevent MMR outbreaks.

Multimodal safety assessment of measles-mumps-rubella vaccination after pediatric liver transplantation.

Live-attenuated vaccines are currently contraindicated in solid-organ transplant recipients. However, the risk of vaccine-preventable infections is lifelong, and can be particularly severe after transplantation. In this prospective interventional national cohort study, 44 pediatric liver transplant recipients with measles IgG antibodies <150 IU/L (below seroprotection threshold) received measles-mumps-rubella vaccine (MMR) at a median of 6.3 years posttransplantation (interquartile range, 4.0 to 10.9). A maximum of two additional doses were administered in nonresponders or when seroprotection was lost. Vaccine responses occurred in 98% (95% confidence interval [CI], 88-100) of patients. Seroprotection at 1-, 2-, and 3-year follow-up reached 62% (95% CI, 45-78), 86% (95% CI, 70-95), and 89% (95% CI, 67-99), respectively. All patients responded appropriately to the booster dose(s). Vaccinations were well tolerated and no serious adverse event attributable to vaccination was identified during the 8-week follow-up period (or later), using a multimodal approach including standardized telephone interviews, diarized side effect reporting, and monitoring of vaccinal virus shedding. We conclude that live attenuated MMR vaccine can be administered in liver transplant recipients fulfilling specific eligibility criteria (>1 year posttransplantation, low immunosuppression, lymphocyte count ≥0.75 G/L), inducing seroprotection in most subjects. (Clinicaltrials.gov number NCT01770119).

Reconstructing the transmission dynamics of rubella in Japan, 2012-2013.

BACKGROUND: Japan experienced a nationwide rubella epidemic from 2012 to 2013, mostly in urban prefectures with large population sizes. The present study aimed to capture the spatiotemporal patterns of rubella using a parsimonious metapopulation epidemic model and examine the potential usefulness of spatial vaccination. METHODOLOGY/PRINCIPAL FINDINGS: A metapopulation epidemic model in discrete time and space was devised and applied to rubella notification data from 2012 to 2013. Employing a piecewise constant model for the linear growth rate in six different time periods, and using the particle Markov chain Monte Carlo method, the effective reproduction numbers were estimated at 1.37 (95% CrI: 1.12, 1.77) and 1.37 (95% CrI: 1.24, 1.48) in Tokyo and Osaka groups, respectively, during the growing phase of the epidemic in 2013. The rubella epidemic in 2012 involved substantial uncertainties in its parameter estimates and forecasts. We examined multiple scenarios of spatial vaccination with coverages of 1%, 3% and 5% for all of Japan to be distributed in different combinations of prefectures. Scenarios indicated that vaccinating the top six populous urban prefectures (i.e., Tokyo, Kanagawa, Osaka, Aichi, Saitama and Chiba) could potentially be more effective than random allocation. However, greater uncertainty was introduced by stochasticity and initial conditions such as the number of infectious individuals and the fraction of susceptibles. CONCLUSIONS: While the forecast in 2012 was accompanied by broad uncertainties, a narrower uncertainty bound of parameters and reliable forecast were achieved during the greater rubella epidemic in 2013. By better capturing the underlying epidemic dynamics, spatial vaccination could substantially outperform the random vaccination.

Protocolo del Sistema Nacional de Vigilancia Epidemiológica de enfermedades inmunoprevenibles. No. 06 / Protocol of the National Epidemiological Surveillance System of immunoprevenible diseases. No. 06

Estos protocolos están dirigido a personal médico, paramédico y otros profesionales que realizan acciones gerenciales y operativas de vigilancia epidemiológica en los servicios de salud del país, y están divididos en varios tomos para dar a conocer y actualizar la identificación y medidas de control para diversos padecimientos a fin de continuar con el mejoramiento de las capacidades técnicas de los trabajadores de salud, que permita planificar la prestación de servicios con decisiones partiendo de un enfoque epidemiológico comprobado, para responder a los cambios de tendencias epidemiológicas y con ello contribuir al fortalecimiento de prácticas asertivas de la salud pública de nuestro país. La vigilancia epidemiológica de las enfermedades prevenibles con vacuna, busca reducir la mortalidad y morbilidad por infecciones inmunoprevenibles. La vigilancia epidemiológica, es fundamental para evaluar el impacto de las intervenciones y la toma de decisiones de acuerdo al análisis permanente de la situación de salud.

Assessment of the implementation of the infectious diseases screening programmes among pregnant women in the Lesser Poland region and comparison with similar programmes conducted in other European Union countries.

OBJECTIVES: The aim of the study was to assess the level of implementation of recommendations of the Ministry of Health regarding infectious disease screening during pregnancy. MATERIAL AND METHODS: The study included 477 patients who were admitted to the delivery room between December 2015 and February 2016. Data on screening test results were collected based on medical records covering the period before the admission. RESULTS: The Human Immunodeficiency Virus (HIV) screening was conducted in 410 (86%). 460 (96%) of patients were screened for Hepatitis B Virus (HBV) and 427 (89.5%) for Hepatitis C Virus (HCV). Syphilis screening covered 465 (97.5%) of patients. Immunoglobulin M (IgM) titer against Rubella Virus (RV) was assessed in 218 (45%) patients and immunoglobulin G (IgG) in 319 (66.9%). Screening for Toxoplasma gondii based on assessment of IgM titer was conducted in 440 (92%) patients while IgG titter was assessed in 413 (86.6%). 343 (71.9%) patients had obtained vaginal swabs for Group B Streptococci (GBS) while the anal swabs were taken only from 268 (56.2%) patients. CONCLUSIONS: Coverage of screening for syphilis and HBV was similar to the countries with highest prevalence of conducting such screening, on the other hand RV screening place as among countries with lowest prevalence. There is an increasing trend in conducting HIV screening. Screening for HCV and toxoplasmosis is at satisfactory level and Poland is one of a few European countries offering such screening. The screening for GBS is insufficient which result in excessive use of intrapartum antibiotic prophylaxis.

External Quality Assessment for Rubella Virus RNA Detection Using Armored RNA in China.

BACKGROUND: Although tremendous efforts have been made to reduce rubella incidence, there are still 300 new cases of congenital rubella syndrome daily; thus, rubella infections remain one of the leading causes of preventable congenital birth defects. An effective surveillance system, which could be achieved and maintained by using an external quality assessment program, is critical for prevention and control of this disease. METHODS: Armored RNAs, which are noninfectious and RNase-resistant, were used for encapsulation of the E1 gene of rubella virus and for preparation of a 10-specimen panel for external quality assessment. Thirty-two laboratories across mainland China that used nucleic acid tests for rubella virus RNA detection were included in the external quality assessment program organized by the National Center for Clinical Laboratories of China. RESULTS: Different kinds of commercial kits were used by the laboratories for nucleic acid extraction and TaqMan real-time reverse-transcription PCR for rubella virus RNA detection; 99.2% sensitivity and 100% specificity were achieved in this external quality assessment program. CONCLUSIONS: Most of the participating laboratories obtained accurate results for rubella nucleic acid tests, thereby achieving the quality required for regional rubella and congenital rubella syndrome elimination.

An inkjet printed, roll-coated digital microfluidic device for inexpensive, miniaturized diagnostic assays.

The diagnosis of infectious disease is typically carried out at the point-of-care (POC) using the lateral flow assay (LFA). While cost-effective and portable, LFAs often lack the clinical sensitivity and specificity required for accurate diagnoses. In response to this challenge, we introduce a new digital microfluidic (DMF) platform fabricated using a custom inkjet printing and roll-coating process that is scalable to mass production. The performance of the new devices is on par with that of traditional DMF devices fabricated in a cleanroom, with a materials cost for the new devices of only US $0.63 per device. To evaluate the usefulness of the new platform, we performed a 13-step rubella virus (RV) IgG immunoassay on the inkjet printed, roll-coated devices, which yielded a limit of detection of 0.02 IU mL-1, well below the diagnostic cut-off of 10 IU mL-1 for RV infection and immunity. We propose that this represents a breakthrough for DMF, lowering the costs to a level such that the new platforms will be an attractive alternative to LFAs for the diagnosis of infectious disease at the POC.

Estimating the burden of rubella virus infection and congenital rubella syndrome through a rubella immunity assessment among pregnant women in the Democratic Republic of the Congo: Potential impact on vaccination policy.

BACKGROUND: Rubella-containing vaccines (RCV) are not yet part of the Democratic Republic of the Congo's (DRC) vaccination program; however RCV introduction is planned before 2020. Because documentation of DRC's historical burden of rubella virus infection and congenital rubella syndrome (CRS) has been minimal, estimates of the burden of rubella virus infection and of CRS would help inform the country's strategy for RCV introduction. METHODS: A rubella antibody seroprevalence assessment was conducted using serum collected during 2008-2009 from 1605 pregnant women aged 15-46years attending 7 antenatal care sites in 3 of DRC's provinces. Estimates of age- and site-specific rubella antibody seroprevalence, population, and fertility rates were used in catalytic models to estimate the incidence of CRS per 100,000 live births and the number of CRS cases born in 2013 in DRC. RESULTS: Overall 84% (95% CI 82, 86) of the women tested were estimated to be rubella antibody seropositive. The association between age and estimated antibody seroprevalence, adjusting for study site, was not significant (p=0.10). Differences in overall estimated seroprevalence by study site were observed indicating variation by geographical area (p⩽0.03 for all). Estimated seroprevalence was similar for women declaring residence in urban (84%) versus rural (83%) settings (p=0.67). In 2013 for DRC nationally, the estimated incidence of CRS was 69/100,000 live births (95% CI 0, 186), corresponding to 2886 infants (95% CI 342, 6395) born with CRS. CONCLUSIONS: In the 3 provinces, rubella virus transmission is endemic, and most viral exposure and seroconversion occurs before age 15years. However, approximately 10-20% of the women were susceptible to rubella virus infection and thus at risk for having an infant with CRS. This analysis can guide plans for introduction of RCV in DRC. Per World Health Organization recommendations, introduction of RCV should be accompanied by a campaign targeting all children 9months to 14years of age as well as vaccination of women of child bearing age through routine services.

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.

Genotypes of rubella virus and the epidemiology of rubella infections in the Democratic Republic of the Congo, 2004-2013.

Rubella is a viral infection that may cause fetal death or congenital defects, known as congenital rubella syndrome (CRS), during early pregnancy. The World Health Organization (WHO) recommends that countries assess the burden of rubella and CRS, including the determination of genotypes of circulating viruses. The goal of this study was to identify the genotypes of rubella viruses in the Democratic Republic of the Congo (DRC). Serum or throat swab samples were collected through the measles surveillance system. Sera that tested negative for measles IgM antibody were tested for rubella IgM antibody. Serum collected within 4 days of rash onset and throat swabs were screened by real-time RT-PCR for rubella virus RNA. For positive samples, an amplicon of the E1 glycoprotein gene was amplified by RT-PCR and sequenced. 11733 sera were tested for rubella IgM and 2816 (24%) were positive; 145 (5%) were tested for the presence of rubella RNA by real-time RT-PCR and 10 (7%) were positive. Seventeen throat swabs were analyzed by RT-PCR and three were positive. Sequences were obtained from eight of the positive samples. Phylogenetic analysis showed that the DRC rubella viruses belonged to genotypes 1B, 1E, 1G, and 2B. This report provides the first information on the genotypes of rubella virus circulating in the DRC. These data contribute to a better understanding of rubella burden and the dynamics of rubella virus circulation in Africa. Efforts to establish rubella surveillance in the DRC are needed to support rubella elimination in Africa. J. Med. Virol. 88:1677-1684, 2016. © 2016 Wiley Periodicals, Inc.

An epidemiological assessment towards elimination of rubella and congenital rubella syndrome in Singapore.

OBJECTIVE: In line with regional and global goals for the elimination of rubella and congenital rubella syndrome (CRS), we reviewed the epidemiological situation in Singapore, based on surveillance reports on rubella and CRS, national immunization coverage and seroprevalence surveys. The aim of our review was to identify current gaps and steps taken to achieve the targets set by the World Health Organization (WHO) Western Pacific Regional Office (WPRO). METHODS: Epidemiological data on clinical and laboratory-confirmed rubella cases, including CRS, notified to the Communicable Diseases Division, Ministry of Health, Singapore, from 2003 to 2013 were collated and analyzed. Vaccination coverage against rubella was obtained from the National Immunization Registry and School Health Services of the Health Promotion Board. The changing prevalence of rubella was determined from periodic serological surveys. FINDINGS: The incidence of indigenous rubella cases per million population decreased from 37.2 in 2008 to 7.6 in 2013 and there had been no indigenous case of CRS in 2012 and 2013. Therapeutic abortions performed due to rubella infections had become uncommon. The annual measles, mumps, and rubella (MMR) vaccination coverage in childhood population remained high ranging from 93% to 96%. The overall susceptibility to rubella in women aged 18-44 years had reduced significantly from 15.8% in 2004 to 11.0% in 2010. The prevalence of IgG antibody against rubella among Singapore children aged 1-17 years was maintained at 87.3% in 2008-2010. CONCLUSION: All available data indicated that Singapore has made good progress towards the elimination of rubella and CRS. It has attained the targets set by the WHO WPRO for 2015. In preparation for verification of rubella elimination, an enhanced surveillance system has been implemented to ensure that all reported cases are laboratory confirmed, and genotyping of rubella virus strains isolated is carried out to provide evidence for interruption of endemic transmission.

Long-term longitudinal assessment of postoperative outcomes after congenital cataract surgery in children with congenital rubella syndrome.

PURPOSE: To assess the intraoperative and long-term longitudinal postoperative outcomes of cataract surgery in children with congenital rubella syndrome. SETTING: Iladevi Cataract & IOL Research Centre, Ahmedabad, India. DESIGN: Prospective observational clinical study. METHODS: Children with congenital rubella syndrome who had cataract surgery were enrolled. All microphthalmic eyes were left aphakic. A 1-piece hydrophobic acrylic intraocular lens was implanted in the capsular bag in eyes without microphthalmos. The postoperative observations included complications and visual assessments up to 5 years. RESULTS: The mean age of the 21 children (37 eyes) was 3.97 months ± 2.1 (SD). Intraocular lens implantation was performed in 12 eyes (32.4%), while 25 eyes (67.6%) were left aphakic. Postoperatively, the median follow-up was 60.79 months. Posterior synechiae were observed in 22 eyes (59.5%) and visual axis opacification in 9 eyes (24.3%). Secondary glaucoma was observed in 16 eyes (43.2%), of which 14 were aphakic and 1 was pseudophakic. Nine eyes required trabeculectomy. Age at surgery and ocular comorbidities were statistically significantly associated with secondary glaucoma (P<.05, χ(2) test and Kendall τB criteria P<.05). The mean corrected distance visual acuity at the final follow-up was 0.72 ± 0.56 logMAR. CONCLUSIONS: The long-term results suggest good visual outcomes can be obtained with congenital cataract associated with congenital rubella syndrome after early surgical intervention. The rate of serious postoperative complications was acceptable.

Serological assessment of measles-rubella vaccination catch-up campaign among university students.

BACKGROUND: In Japan, 5000-300,000 persons contracted measles every year until 2001. The measles/rubella-combined (MR) vaccination at age 17-18 years (phase 4 MR vaccination: MR-IV) was launched in 2008 in Japan as a measles-rubella catch-up campaign. A serological assessment of this campaign has not been thoroughly performed. METHODS: Titers of anti-measles and anti-rubella immunoglobulin G antibodies, and past medical history including measles and rubella vaccination and infection were obtained from first-year university students in 2008 and 2009, and the immune status against measles and rubella was compared between students at the target MR-IV age (the target age group) and those 1 year older than the target age (non-target age group). RESULTS: A total of 186 students were in the target age group and 146 were in the non-target age group. The proportion of students with a history of measles and rubella infection was not significantly different between the two groups (8.8% vs. 6.3%, P = 0.41 and 11.0% vs. 9.9%, P = 0.75, respectively). A history of two or more measles and rubella vaccinations was significantly more frequent in the target age group (85.2% and 54.9%, respectively) than in the non-target age group (20.8% and 13.2%, respectively; both P < 0.001). Prevalence of seropositivity for measles and for rubella was also higher in the target age group (98.9% and 97.8%, respectively) than in the non-target age group (91.0% and 87.5%, respectively; both P < 0.001). CONCLUSIONS: The MR-IV catch-up campaign helped achieve herd immunity and will contribute to the elimination of measles and rubella.

How useful is a history of rubella vaccination for determination of disease susceptibility? A cross-sectional study at a public funded health clinic in Malaysia.

BACKGROUND: Identification of pregnant women susceptible to rubella is important as vaccination can be given postpartum to prevent future risks of congenital rubella syndrome. However, in Malaysia, rubella antibody screening is not offered routinely to pregnant women in public funded health clinics due to cost constraint. Instead, a history of rubella vaccination is asked to be provided to establish the women's risk for rubella infection. The usefulness of this history, however, is not established. Thus, this paper aimed to determine the usefulness of a history of rubella vaccination in determining rubella susceptibility in pregnant women. METHODS: A cross-sectional study was conducted on 500 pregnant women attending a public funded health clinic. Face-to-face interviews were conducted, and demographic data and history of rubella vaccination were obtained. Anti-rubella IgG test was performed. RESULTS: A majority of the women (66.6%) had a positive vaccination history. Of these, 92.2% women were immune. A third (33.4%) of the women had a negative or unknown vaccination history, but 81.4% of them were immune to rubella. The sensitivity and specificity of a history of rubella vaccination in identifying disease susceptibility was 54.4% (95% CI: 40.7, 67.4%) and 69.3% (95% CI: 64.7, 73.5%) respectively; the positive predictive value was 18.6% (95% CI: 13.1, 25.5%) and the negative predictive value was 92.2% (95% CI: 88.6, 94.7%). CONCLUSIONS: A vaccination history of rubella had a poor diagnostic value in predicting rubella susceptibility. However, obtaining a vaccination history is inexpensive compared with performing a serological test. A cost-utility analysis would be useful in determining which test (history versus serological test) is more cost-effective in a country with resource constraint.

Cost-effectiveness analysis of rubella screening strategies using electronic medical records.

OBJECTIVE: The redundancy of routine laboratory tests in medicine has become increasingly more apparent in the age of electronic medical records (EMRs). The purpose of this study was to determine whether targeted screening strategies are more cost-effective than the current standard of universal screening of pregnant women for immunity to rubella. STUDY DESIGN: A decision analysis model was used to evaluate three strategies: universal screening, screening if a previous titer was not available, and use of an "alert" in the EMR to prompt screening. Cost, probability, and utility values were derived from the literature and institutional data from Lyndon B. Johnson General Hospital. One-way sensitivity analyses were performed on all cost and probability values. RESULTS: The strategy of an EMR alert was most cost-effective, with a cost of $0.27 per quality-adjusted life years (QALY). The model was robust to all costs and probability values over their respective ranges. CONCLUSIONS: Although all strategies were cost-effective compared with traditional industry benchmarks of $50,000/QALY, the EMR alert strategy is most cost-effective. Implementing an EMR alert may lead to a more cost-effective approach to prenatal evaluation of rubella immunity.