Fetal risk associated with rubella vaccination during pregnancy

The protective role of maternal genetic immunization on maternal-fetal health and welfare

Pregnancy is a critical period associated with alterations in physiologic, biologic, and immunologic processes, which can affect maternal-fetal health through development of several infectious diseases. At birth, neonates have an immature immune system that makes them more susceptible to severe viral infections and diseases. For this reason, different maternal nutritional and immunization interventions have been used to improve the immune and health status of the mother and her neonate through passive immunity. Here, we reviewed the protective role of maternal immunization with different types of vaccines, especially genetic vaccines, during pregnancy in maternal-fetal health, immune response, colostrum quality, immune response, and anti-oxidative status. For this purpose, we have used different scientific databases (PubMed and Google Scholar) and other official web pages. We customized the search period range from the year 2000 to 2023 using the key words "maternal immunization" OR "gestation period/pregnancy" OR "genetic vaccination" OR "maternal-fetal health" OR "micronutrients" OR "neonatal immunity" "oxidative stress" OR "colostrum quality". The evidence demonstrated that inactivated or killed vaccines produced significant immune protection in the mother and fetus. Furthermore, most recent studies have suggested that the use of genetic vaccines (mRNA and DNA) during pregnancy is efficient at triggering the immune response in mother and neonate without the risk of undesired pregnancy outcomes. However, factors such as maternal redox balance, nutritional status, and the timing of immunization play essential roles in regulating immune response inflammatory status, antioxidant capacity, and the welfare of both the pregnant mother and her newborn.

Congenital Rubella Syndrome Following Rubella Vaccination During Pregnancy

Rubella vaccine is usually given in combination with measles and mumps vaccines as a measles-mumps-rubella vaccination. Because it contains live attenuated virus, its use is contraindicated during pregnancy. However, since the introduction of rubella vaccine, no cases of congenital rubella syndrome have been reported following vaccination during pregnancy. We report a case of a female infant, born to a woman inadvertently vaccinated with measles-mumps-rubella vaccination early in pregnancy, who manifested a phenotype of cardiac and neurologic defects, neurodevelopmental delay, and lymphocytopenia consistent with congenital rubella syndrome.

[Vaccinations for pregnant women and women attempting to become pregnant]

Infektionen sind eine wichtige potenzielle Gefahrenquelle für Schwangere und ihre ungeborenen Kinder. Schwangere und Frauen mit Kinderwunsch sollten sich daher fachkundig darüber beraten lassen, welche Impfungen vor bzw. während einer Schwangerschaft sinnvoll sind. Zur Impfberatung gehören auch Fragestellungen zu Reiseimpfungen, insbesondere wenn das Reiseziel in einem Endemiegebiet für Erkrankungen wie Malaria, Gelbfieber, Tuberkulose, Hepatitis, Human-immunodeficiency-virus-assoziierte Erkrankungen, Leishmaniose, Toxoplasmose und Japanische Enzephalitis liegt. Grundsätzlich können alle Toxoidimpfstoffe, inaktivierten Impfstoffe und Immunglobuline in der Schwangerschaft verabreicht werden, Lebendimpfstoffe sind kontraindiziert. Empfehlenswerte Impfungen in der Schwangerschaft sind Tetanus, Diphtherie, Pertussis im Falle eines fehlenden Impfschutzes, die saisonale Influenzaimpfung und aktuell die Coronavirus-disease-19(COVID-19)-Impfung ab dem zweiten Trimenon. Zu den empfohlenen Reiseschutzimpfungen zählen alle Standardimpfungen, das heißt die Grundimmunisierung gegen Rotaviren, Tetanus, Diphtherie, Pertussis, Haemophilus influenzae Typ B, Poliomyelitis, Hepatitis B, Pneumokokken, Meningokokken, Masern, Mumps, Röteln, Varizellen, humanes Papillomavirus und Influenza. Darüber hinaus hat in der Reisemedizin der Immunschutz gegen Hepatitis A einen hohen Stellenwert. Nach den internationalen Gesundheitsempfehlungen der World Health Organization ist zur Einreise in bzw. Ausreise aus bestimmten Ländern eine zusätzliche spezifische Impfvorschrift für die Gelbfieber- und Poliomyelitisimpfung vorgesehen. Einzelne Länder haben darüber hinaus zusätzliche Impfvorschriften für die Ein- und Ausreise. „Indikationsimpfungen“ setzen ein entsprechendes lokales Risiko voraus.

Evaluating the Association of Stillbirths After Maternal Vaccination in the Vaccine Safety Datalink

OBJECTIVE

To evaluate whether the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices recommended influenza and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccinations in pregnancy are associated with increased risk of stillbirth.

METHODS

We performed a case-control study in the Vaccine Safety Datalink that was matched 1:4 on site, month, and year of last menstrual period, comparing the odds of vaccination in pregnancies that ended in stillbirth (defined as fetal loss at or after 20 weeks of gestation) compared with those that ended in live birth from January 1, 2012, to September 30, 2015. We included patients with singleton pregnancies that ended in stillbirth or live birth who had at least one prenatal care visit, pregnancy dating information, and continuous health plan enrollment for the duration of pregnancy. Medical records for all stillbirths were reviewed. We were statistically powered to detect an odds ratio (OR) of 1.37 when evaluating the association between influenza or Tdap vaccination and stillbirth. We also examined stillbirth rates in pregnant patients aged 14-49 years in the Vaccine Safety Datalink between 2007 and 2015.

RESULTS

In our matched analysis of 795 confirmed stillbirths in the case group and 3,180 live births in the control group, there was no significant association between influenza vaccination during pregnancy and stillbirth (343/795 [43.1%] stillbirths in the case group vs 1,407/3,180 [44.3%] live births in the control group, OR 0.94, adjusted OR 0.95, 95% CI 0.79-1.14, P=.54) and no significant association between Tdap vaccination during pregnancy and stillbirth (184/795 [23.1%] stillbirths in the case group vs 746/3,180 [23.5%] live births in the control group, OR 0.97, aOR 0.96, 95% CI 0.76-1.28, P=.91). From 2007 to 2015, the stillbirth rate in the Vaccine Safety Datalink was 5.2 per 1,000 live births and stillbirths.

CONCLUSION

No association was found between vaccination during pregnancy and the odds of stillbirth. These findings support the safety of ACIP recommendations for vaccination during pregnancy.

The Protective Role of Maternal Immunization in Early Life

With birth, the newborn is transferred from a quasi-sterile environment to the outside world. At this time, the neonatal immune system is inexperienced and continuously subject to a process of development as it encounters different antigenic stimuli after birth. It is initially characterized by a bias toward T helper 2 phenotype, reduced T helper 1, and cytotoxic responses to microbial stimuli, low levels of memory, and effector T and B cells and a high production of suppressive T regulatory cells. The aim of this setting, during fetal life, is to maintain an anti-inflammatory state and immune-tolerance. Maternal antibodies are transferred during pregnancy through the placenta and, in the first weeks of life of the newborn, they represent a powerful tool for protection. Thus, optimization of vaccination in pregnancy represents an important strategy to reduce the burden of neonatal infections and sepsis. Beneficial effects of maternal immunization are universally recognized, although the optimal timing of vaccination in pregnancy remains to be defined. Interestingly, the dynamic exchange that takes place at the fetal-maternal interface allows the transfer not only of antibodies, but also of maternal antigen presenting cells, probably in order to stimulate the developing fetal immune system in a harmless way. There are still controversial effects related to maternal immunization including the so called "immunology blunting," i.e., a dampened antibody production following infant's vaccination in those infants who received placentally transferred maternal immunity. However, clinical relevance of this phenomenon is still not clear. This review will provide an overview of the evolution of the immune system in early life and discuss the benefits of maternal vaccination. Current maternal vaccination policies and their rationale will be summarized on the road to promising approaches to enhance immunity in the neonate.

Safety evaluation of adverse events following vaccination with Havrix, Engerix-B or Twinrix during pregnancy

BACKGROUND

Vaccination of pregnant women against hepatitis A virus (HAV) or hepatitis B virus (HBV) may benefit the mother and the fetus but is not routinely recommended. However, the risk associated with vaccination should be weighed against the risk of HAV or HBV infection. Data on safety profiles after hepatitis A, B or combined AB immunization during pregnancy are limited.

METHODS

We searched the GSK Worldwide Safety Database for adverse events (AEs) following immunization of pregnant women with HAV (Havrix, GSK), HBV (Engerix-B, GSK) or the combined hepatitis AB (Twinrix, GSK) vaccine since market authorization through 31 January 2018, covering at least 25 years. AE reports (spontaneous, post-marketing surveillance and clinical trial cases) in the GSK Worldwide Safety Database were identified using a systematic search and were reviewed by clinicians to ascertain pregnancy status at time of vaccination and characterize adverse pregnancy outcomes, including pregnancy-related AEs and AEs in infants regardless of the causality assessment.

RESULTS

Overall, 613, 700 and 363 pregnancies with exposure to Havrix, Engerix-B and Twinrix, respectively, were reported. Of these, 378, 339 and 194 were analyzed. The most frequently identified pregnancy outcomes were live infants (288, 223 and 151), spontaneous abortions (43, 57 and 26) and elective terminations (25, 24 and 9). A total of 19, 29 and 10 cases of congenital anomalies were reported. Of these, 17, 20 and 7 were major birth defects. The most commonly reported pregnancy-related AE and AE in infants were premature delivery (28) and jaundice (11), respectively. No maternal deaths were reported. Congenital anomalies were reported in all recorded infant deaths.

CONCLUSIONS

This review did not indicate any concerning pattern of adverse pregnancy outcomes following exposure to any of the 3 vaccines during pregnancy.

Safety of Administering Live Vaccines During Pregnancy: A Systematic Review and Meta-Analysis of Pregnancy Outcomes

Live-attenuated vaccines (LAV) are currently contraindicated during pregnancy, given uncertain safety records for the mother-infant pair. LAV might, however, play an important role to protect them against serious emerging diseases, such as Ebola and Lassa fever. For this systematic review we searched relevant databases to identify studies published up to November 2019. Controlled observational studies reporting pregnancy outcomes after maternal immunization with LAV were included. The ROBINS-I tool was used to assess risk of bias. Pooled odds ratios (OR) were obtained under a random-effects model. Of 2831 studies identified, fifteen fulfilled inclusion criteria. Smallpox, rubella, poliovirus, yellow fever and dengue vaccines were assessed in these studies. No association was found between vaccination and miscarriage (OR 0.98, 95% CI 0.87-1.10), stillbirth (OR 1.04, 95% CI 0.74-1.48), malformations (OR 1.09, 95% CI 0.98-1.21), prematurity (OR 0.99, 95% CI 0.90-1.08) or neonatal death (OR 1.06, 95% CI 0.68-1.65) overall. However, increased odds of malformations (OR 1.24; 95% CI 1.03-1.49) and miscarriage after first trimester immunization (OR 4.82; 95% CI 2.38-9.77) was found for smallpox vaccine. Thus, we did not find evidence of harm related to LAV other than smallpox with regards to pregnancy outcomes, but quality of evidence was very low. Overall risks appear to be small and have to be balanced against potential benefits for the mother-infant pair.

Safety profile of rubella vaccine administered to pregnant women: A systematic review of pregnancy related adverse events following immunisation, including congenital rubella syndrome and congenital rubella infection in the foetus or infant

BACKGROUND

Data on the safety of inadvertent rubella vaccination in pregnancy is important for rubella vaccination programs aimed at preventing congenital rubella syndrome.

METHODS

The association between monovalent rubella or combination vaccinations in or shortly before pregnancy and potential harm to the foetus was examined by conducting a systematic review and meta-analysis using fixed effect methods and simulation.

RESULTS

Four cohort studies of inadvertently vaccinated and unvaccinated women were found, 15 cohorts of pregnant women who were rubella susceptible at time of inadvertent vaccination and 9 cohort studies with no information on susceptibility and case series. No case of vaccine associated congenital rubella syndrome (CRS) was identified. Cohort studies with an unvaccinated comparison group were limited in number and size, and based on these only a theoretical additional risk of 6 or more cases of CRS per 1000 vaccinated women (0% observed, upper 95% CI 0.6%) could be excluded. Based on cohorts of vaccinated rubella susceptible pregnant women a maximum theoretical risk of 1 CRS case in 1008 vaccinated women (0% observed, upper 95% CI 0.099%) was estimated. Asymptomatic rubella vaccine virus infection of the neonate was also noted (fixed effects estimate of risk overall 1.74%, 95% CI 1.21, 2.28).

CONCLUSION

There is no evidence that CRS is caused by rubella-containing vaccines but transplacental vaccine virus infection can occur. CRS is effectively prevented by vaccination, thus the risk/benefit balance is unequivocally in favour of vaccination. The data confirm previous recommendations that inadvertent vaccination during pregnancy is not an indication for termination of pregnancy.

Immunizations during pregnancy: How, when and why

Maternal immunization during pregnancy provide protection for the mother and the fetus against certain pathogens. Immunizations during pregnancy are divided to routine immunizations recommended for all pregnant women, immunizations for certain medical indications and vaccines that are potentially harmful during pregnancy and should be avoided. We conducted a comprehensive review of the literature regarding immunizations during pregnancy. The search terms used were immunization, vaccine, pregnancy, influenza, pertussis, safety and efficacy. We gathered all available guidelines on vaccination during pregnancy. Generally, vaccines are allowed during pregnancy when the benefits outweigh the risks. Tdap and inactivated flu vaccines are routinely recommended during pregnancy. Vaccines containing live attenuated viruses are contraindicated during pregnancy. These are LAIV influenza, MMR, Varicella, Zoster, BCG and smallpox pre-exposure. All other vaccines are given when medically indicated and the possible benefits outweigh the risks. Obstetricians and gynecologists should be familiar with the indications of vaccination during pregnancy. Vaccination coverage of pregnant women with routinely recommended vaccines has increased but further efforts are needed. Our aim is to review vaccination practices during pregnancy, demonstrate the benefits and dangers of different vaccines, evaluate their effectiveness and define the proper timing of vaccination.

MMR and MMRV vaccines

Measles, mumps, rubella and varicella are viral infections which can implicate seriously long-term sequelae of infected individuals or even the unborn child. Vaccines against the individual diseases have long been available. Global measles vaccination is estimated to have prevented more than 20million deaths during 2000-2015. During the same time period, measles incidence decreased from 146 to 36 cases per million populations. Today vaccinations against measles, mumps, rubella and varicella are now carried out mainly with combination vaccines. These are today known as immunogenic and safe. MMRV had similar immunogenicity and overall safety profiles to MMR administered with or without varicella vaccine. This issue provides a review of the different vaccines, mode of administration, catch up immunization and postexposure prophylaxis as well as contraindications and adverse effects of the immunization against measles, mumps, rubella, and varicella. The article presents an overview of important information of preventing these diseases with a focus on the existing combination vaccines.

Modeling the Transmission of Measles and Rubella to Support Global Management Policy Analyses and Eradication Investment Cases

Policy makers responsible for managing measles and rubella immunization programs currently use a wide range of different vaccines formulations and immunization schedules. With endemic measles and rubella transmission interrupted in the region of the Americas, all five other regions of the World Health Organization (WHO) targeting the elimination of measles transmission by 2020, and increasing adoption of rubella vaccine globally, integrated dynamic disease, risk, decision, and economic models can help national, regional, and global health leaders manage measles and rubella population immunity. Despite hundreds of publications describing models for measles or rubella and decades of use of vaccines that contain both antigens (e.g., measles, mumps, and rubella vaccine or MMR), no transmission models for measles and rubella exist to support global policy analyses. We describe the development of a dynamic disease model for measles and rubella transmission, which we apply to 180 WHO member states and three other areas (Puerto Rico, Hong Kong, and Macao) representing >99.5% of the global population in 2013. The model accounts for seasonality, age-heterogeneous mixing, and the potential existence of preferentially mixing undervaccinated subpopulations, which create heterogeneity in immunization coverage that impacts transmission. Using our transmission model with the best available information about routine, supplemental, and outbreak response immunization, we characterize the complex transmission dynamics for measles and rubella historically to compare the results with available incidence and serological data. We show the results from several countries that represent diverse epidemiological situations to demonstrate the performance of the model. The model suggests relatively high measles and rubella control costs of approximately $3 billion annually for vaccination based on 2013 estimates, but still leads to approximately 17 million disability-adjusted life years lost with associated costs for treatment, home care, and productivity loss costs of approximately $4, $3, and $47 billion annually, respectively. Combined with vaccination and other financial cost estimates, our estimates imply that the eradication of measles and rubella could save at least $10 billion per year, even without considering the benefits of preventing lost productivity and potential savings from reductions in vaccination. The model should provide a useful tool for exploring the health and economic outcomes of prospective opportunities to manage measles and rubella. Improving the quality of data available to support decision making and modeling should represent a priority as countries work toward measles and rubella goals.

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.

The Costs and Valuation of Health Impacts of Measles and Rubella Risk Management Policies

National and global health policymakers require good information about the costs and benefits of their investments in measles and rubella immunization programs. Building on our review of the existing measles and rubella health economics literature, we develop inputs for use in regional and global models of the expected future benefits and costs of vaccination, treatment, surveillance, and other global coordination activities. Given diversity in the world and limited data, we characterize the costs for countries according to the 2013 World Bank income levels using 2013 U.S. dollars (2013$US). We estimate that routine immunization and supplemental immunization activities will cost governments and donors over 2013$US 2.3 billion per year for the foreseeable future, with high-income countries accounting for 55% of the costs, to vaccinate global birth cohorts of approximately 134 million surviving infants and to protect the global population of over 7 billion people. We find significantly higher costs and health consequences of measles or rubella disease than with vaccine use, with the expected disability-adjusted life year (DALY) loss for case of disease generally at least 100 times the loss per vaccine dose. To support estimates of the economic benefits of investments in measles and/or rubella elimination or control, we characterize the probabilities of various sequelae of measles and rubella infections and vaccine adverse events, the DALY inputs for health outcomes, and the associated treatment costs. Managing measles and rubella to achieve the existing and future regional measles and rubella goals and the objectives of the Global Vaccine Action Plan will require an ongoing commitment of financial resources that will prevent adverse health outcomes and save the associated treatment costs.

Safety of immunization during pregnancy: a review of the evidence of selected inactivated and live attenuated vaccines

Vaccine-preventable infectious diseases are responsible for significant maternal, neonatal, and young infant morbidity and mortality. While there is emerging scientific evidence, as well as theoretical considerations, indicating that certain vaccines are safe for pregnant women and fetuses, policy formulation is challenging because of perceived potential risks to the fetus. This report presents an overview of available evidence on pregnant women vaccination safety monitoring in pregnant women, from both published literature and ongoing surveillance programs. Safety data were reviewed for vaccines against diseases which increase morbidity in pregnant women, their fetus or infant as well as vaccines which are used in mass vaccination campaigns against diseases. They include inactivated seasonal and pandemic influenza, mono- and combined meningococcal polysaccharide and conjugated vaccines, tetanus toxoid and acellular pertussis combination vaccines, as well as monovalent or combined rubella, oral poliomyelitis virus and yellow fever vaccines. No evidence of adverse pregnancy outcomes has been identified from immunization of pregnant women with these vaccines.

Vaccination to protect against infection of the female reproductive tract

Infection of the female genital tract can result in serious morbidities and mortalities from reproductive disability, pelvic inflammatory disease and cancer, to impacts on the fetus, such as infant blindness. While therapeutic agents are available, frequent testing and treatment is required to prevent the occurrence of the severe disease sequelae. Hence, sexually transmitted infections remain a major public health burden with ongoing social and economic barriers to prevention and treatment. Unfortunately, while there are two success stories in the development of vaccines to protect against HPV infection of the female reproductive tract, many serious infectious agents impacting on the female reproductive tract still have no vaccines available. Vaccination to prevent infection of the female reproductive tract is an inherently difficult target, with many impacting factors, such as appropriate vaccination strategies/mechanisms to induce a suitable protective response locally in the genital tract, variation in the local immune responses due to the hormonal cycle, selection of vaccine antigen(s) that confers effective protection against multiple variants of a single pathogen (e.g., the different serovars of Chlamydia trachomatis) and timing of the vaccine administration prior to infection exposure. Despite these difficulties, there are numerous ongoing efforts to develop effective vaccines against these infectious agents and it is likely that this important human health field will see further major developments in the next 5 years.

Pregnancy outcomes following rubella vaccination: a prospective study in the state of Rio de Janeiro, Brazil, 2001-2002

BACKGROUND

A rubella mass vaccination campaign targeting 15-29-year-old women was performed in Brazil in 2001-2002. Rubella vaccination was contraindicated during pregnancy. A follow-up protocol was implemented for pregnant women who were vaccinated as well as their newborns. The risks of congenital rubella syndrome (CRS) and congenital rubella infection (CRI) after vaccination were assessed according to the pregnant women's immune status.

METHODS

This was a prospective, noncontrolled study of pregnancy outcomes in women vaccinated against rubella in the state of Rio de Janeiro, including clinical and laboratory evaluations.

RESULTS

Of 2292 reported pregnant women who were vaccinated, 1636 had known outcomes: there were 1577 newborns (96.4%), 52 miscarriages (3.2%), and 7 stillbirths (0.4%). Gestational age at vaccination was ≤ 5 weeks in 75% of the susceptible, vaccinated pregnant women. Nine newborns were positive for immunoglobulin M; 4 were born to susceptible pregnant women, for a 2.0% CRI rate (95% confidence interval, .5%-4.9%); 4 were born to vaccinated pregnant women with indeterminate or unknown status; and 1 had CRS, with a wild-type virus infection.

CONCLUSIONS

The absence of vaccine-related CRS cases further supports recommendations to not interrupt a pregnancy exposed to rubella vaccine virus. Monitoring pregnancy outcomes and CRI with vaccine virus can distinguish between wild-type and vaccine virus infections, especially in situations of viral circulation.

Rubella vaccination of unknowingly pregnant women during mass campaigns for rubella and congenital rubella syndrome elimination, the Americas 2001-2008

BACKGROUND

Due to the significant teratogenicity of rubella virus and the use of a live-attentuated vaccine, pregnancy is a contraindication of receipt of rubella vaccine (RCV). Data collected from several countries that have observed susceptible women who had received RCV during pregnancy documented that no infant with congenital rubella syndrome (CRS) has been born, so the risk is theoretical. As part of the regional initiative to eliminate rubella and CRS in the Americas, one of the key strategies was the vaccination of women of childbearing age. The implementation of mass vaccination campaigns targeting women of childbearing age in Argentina, Brazil, Costa Rica, Ecuador, El Salvador, and Paraguay provided an opportunity to further increase the body of knowledge on the safety of rubella vaccine if an unknowingly pregnant woman is vaccinated in early pregnancy.

METHODS

Using a standard protocol, women who were unknowingly pregnant or become pregnant ≤ 30 days after receiving RCV were evaluated to determine immunity status (eg, susceptible, immune, and unknown) at the time of vaccination. Susceptible pregnant women were observed to determine the outcome of the pregnancy. For pregnancies that resulted in live births, serum samples were obtained from the newborn for rubella immunoglobulin (Ig) M antibody testing. If the newborn's serum sample was IgM positive, the infant was evaluated for manifestations of CRS.

RESULTS

During the period 2001-2008, 48748253 women of childbearing age were vaccinated in the region of the Americas, 39542253 (81%) of whom were vaccinated in the 6 selected countries. Of these women, 30139 (0.07%) were pregnant or became pregnant ≤1 month after receiving vaccine and were followed up. On the basis of serological evaluation, 2894 (10%) women were classified as susceptible at the time of vaccination; of their pregnancies, 1980 (90%) resulted in a live birth. Sera from 70 (3.5%) of these infants were rubella IgM antibody positive, but none of the infants had features of CRS as a result of rubella vaccination. The maximum theoretical risk for CRS following rubella vaccination of susceptible pregnant women was 0.2%. Conclusions. The results of these studies from 6 select countries provides additional evidence showing an absence of risk of CRS associated with administering rubella vaccine shortly before or during pregnancy.

Unintended vaccination of pregnant adolescents: estimating the scope of the problem and the impact of different pregnancy testing strategies

Among a hypothetical cohort of 11-18-year-old females, we used a probabilistic decision tree model to estimate the number of pregnant adolescent females potentially receiving contraindicated vaccines during well child exams, and to determine the impact of two different pregnancy screening strategies on pregnancy detection rates, vaccine administration and pregnancy detection-associated costs. We found that under current practice conditions, the majority (95-99%) of adolescent pregnancies are likely missed during well child exams, allowing the opportunity to administer contraindicated vaccines. A strategy to test everyone detected the highest proportion of pregnancies, but at a substantial financial cost (USD 12,270,037-USD 19,430,607). Testing was more efficient for older adolescents, but both testing strategies were associated with a significant number of false positive test results (41-98%), regardless of age. These results suggest that systematic pregnancy screening strategies would be effective for preventing pregnant adolescents from receiving contraindicated vaccines, but may not be worth the potentially high financial and psychological costs.

Congenital rubella syndrome: progress and future challenges

Since 1941, when Gregg first described the triad of deafness, cataracts and cardiac disease as the classical clinical manifestations of congenital rubella syndrome (CRS), strong efforts have been implemented around the world to achieve effective preventive strategies. In Costa Rica, vaccination against rubella started in 1972 and in 1986, the combined measles, mumps and rubella vaccine was introduced in the national schedule among 1-year-old children. This vaccination strategy shifted the susceptibility to other groups at child-bearing age. To protect this age group, in 2001 Costa Rica implemented a successful national immunization campaign targeting both men and women aged 15-39 years, followed by postpartum vaccination of women who were pregnant when the campaign was implemented. The epidemiological surveillance system of rubella and CRS cases was strengthened and it was integrated with the investigation and notification system of febrile eruptive diseases. We describe the Costa Rican experience, which has led to similar actions in other countries in Latin America. Challenges and strategies in the elimination of rubella and CRS are also discussed.

A imunização contra a rubéola no primeiro trimestre de gestação pode levar à perda auditiva?

TEMA: embora o risco da Síndrome da Rubéola Congênita após a imunização seja pequeno, é necessário assegurar a imunidade das mulheres em idade fértil, especialmente daquelas com risco mais alto de exposição, visando a prevenção. OBJETIVO: esclarecer o risco que a imunização da rubéola apresenta para a audição do recém nascido, no primeiro trimestre de gestação. CONCLUSÃO: os levantamentos realizados por este estudo permitiram concluir que ainda há um grande caminho a ser percorrido em prol da erradicação da rubéola no Brasil, bem como a diminuição dos riscos de surdez neurossensorial causados pela Síndrome da Rubéola Congênita.

Pre-travel vaccination and medical prophylaxis in the pregnant traveler

BACKGROUND

Practitioners are often fearful of giving vaccinations and prophylactic medications to pregnant travelers. And yet pregnancy is often a time of heightened danger from travel-related infections and illnesses.

METHOD

Literature search and communication with researchers.

RESULTS

With a few exceptions, there is little systematic research regarding the use of prophylactic medications and vaccines during pregnancy. Case reports and small studies do, however, indicate an increased risk in pregnancy from many of the preventable illnesses, and there is some data to support the use of preventive measures.

CONCLUSIONS

The authors present some non-medical interventions that may be used to limit exposure to a number of disease processes. They then review the available information regarding the safety and efficacy of routine and travel-related vaccines as well as prophylactic medications for malaria, diarrhea, motion sickness and altitude sickness. When there are no obstetrical or medical contraindications, travel-related illness can usually be safely prevented during pregnancy in much the same ways as in the non-pregnant state.