Twenty years' experience of rubella vaccination in Sweden: 10 years of selective vaccination (of 12-year-old girls and of women postpartum) and 13 years of a general two-dose vaccination

Rubella virus seropositivity after infection or vaccination as a risk factor for multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a demyelinating disease affecting millions of people worldwide. Hereditary susceptibility and environmental factors contribute to disease risk. Infection with Epstein-Barr virus (EBV) and human herpesvirus 6A (HHV-6A) have previously been associated with MS risk. Other neurotropic viruses, such as rubella virus (RV), are possible candidates in MS aetiopathogenesis, but previous results are limited and conflicting.

METHODS

In this nested case-control study of biobank samples in a Swedish cohort, we analysed the serological response towards RV before the clinical onset of MS with a bead-based multiplex assay in subjects vaccinated and unvaccinated towards RV. The association between RV seropositivity and MS risk was analysed with conditional logistic regression.

RESULTS

Seropositivity towards RV was associated with an increased risk of MS for unvaccinated subjects, even when adjusting for plausible confounders including EBV, HHV-6A, cytomegalovirus and vitamin D (adjusted odds ratio [AOR] = 4.0, 95% confidence interval [CI] 1.8-8.8). Cases also had stronger antibody reactivity towards rubella than controls, which was not seen for other neurotropic viruses such as herpes simplex or varicella zoster. Furthermore, we observed an association between RV seropositivity and MS in vaccinated subjects. However, this association was not significant when adjusting for the aforementioned confounders (AOR = 1.7, 95% CI 1.0-2.9).

CONCLUSIONS

To our knowledge, these are the first reported associations between early RV seropositivity and later MS development. This suggests a broadening of the virus hypothesis in MS aetiology, where molecular mimicry between rubella epitopes and human central nervous system molecules could be an attractive possible mechanism.

Strengthening the case for gender-neutral and the nonavalent HPV vaccine

PURPOSE

The purpose of this review is to highlight the benefits of gender-neutral and the nonavalent human papillomavirus vaccination. Human papillomavirus infection is the most commonly sexually transmitted disease and is known to cause several types of cancers, including cervical, vulvar, vaginal, penile, oropharyngeal, anal, and rectal. 5% of cancers every year are attributable to human papillomavirus infection, with cervical cancer the most common and oropharyngeal cancer estimated to surpass the incidence of cervical cancer by 2020.

METHODS

PubMed and MEDLINE were searched using the following search terms: [(human papillomavirus OR HPV) AND (vaccine OR vaccination)] AND [(gardasil OR gardasil9 OR cervarix OR quadrivalent OR nonavalent OR ninevalent) OR (gender neutral OR male)].

RESULTS

There are currently three different types of human papillomavirus vaccinations and range in cover from four to nine different strains known to cause human disease. Most countries currently only supply vaccination to females; however, recent data point towards both a personal benefit as well as a cost-effective population-based benefit with gender-neutral vaccination. Data from female vaccination only have shown the vaccine to be effective in preventing premalignant cervical lesions, and are believed to have the same effect for other human papillomavirus cancers. Male vaccination not only provides personal benefit but also has a "herd effect" for females by preventing the propagation of the virus.

CONCLUSION

Gender-neutral vaccination provides significant cost-effective benefits for preventing human papillomavirus-related diseases, and this effect is further enhanced by the use of the nonavalent vaccine.

Neighbourhood Deprivation, Individual-Level and Familial-Level Socio-demographic Factors and Risk of Congenital Heart Disease: A Nationwide Study from Sweden

OBJECTIVES

The purpose of the study is to examine whether there is an association between neighbourhood deprivation and incidence of congenital heart disease (CHD), after accounting for family- and individual-level potential confounders.

METHODS

All children aged 0 to 11 years and living in Sweden (n = 748,951) were followed between January 1, 2000 and December 31, 2010. Data were analysed by multilevel logistic regression, with family- and individual-level characteristics at the first level and level of neighbourhood deprivation at the second level.

RESULTS

During the study period, among a total of 748,951 children, 1499 (0.2%) were hospitalised with CHD. Age-adjusted cumulative hospitalisation rates for CHD increased with increasing level of neighbourhood deprivation. In the study population, 1.8 per 1000 and 2.2 per 1000 children in the least and most deprived neighbourhoods, respectively, were hospitalised with CHD. The incidence of hospitalisation for CHD increased with increasing neighbourhood-level deprivation across all family and individual-level socio-demographic categories. The odds ratio (OR) for hospitalisation for CHD for those living in high-deprivation neighbourhoods versus those living in low-deprivation neighbourhoods was 1.23 (95% confidence interval (CI) = 1.04-1.46). In the full model, which took account for age, paternal and maternal individual-level socio-economic characteristics, comorbidities (e.g. maternal type 2 diabetes, OR = 3.03; maternal hypertension, OR = 2.01), and family history of CHD (OR = 3.27), the odds of CHD were slightly attenuated but did not remain significant in the most deprived neighbourhoods (OR = 1.20, 95% CI = 0.99-1.45, p = 0.057).

CONCLUSIONS

This study is the largest so far on neighbourhood influences on CHD, and the results suggest that deprived neighbourhoods have higher rates of CHD, which represents important clinical knowledge. However, the association does not seem to be independent of individual- and family-level characteristics.

HPV vaccination to prevent oropharyngeal carcinoma: What can be learned from anogenital vaccination programs?

Human papillomavirus (HPV) infections are well known causes of anogenital cancers. Recent studies show that HPV also plays a role in oropharyngeal cancer (OPC). A review on the role of HPV vaccination in the prevention of head and neck squamous cell carcinoma (HNSCC) with special emphasis on OPC was conducted and available vaccines and vaccination strategies in HNSCC and OPC are discussed. Prophylactic vaccination is known to be effective for prevention of anogenital HPV infection and precursor lesions in the cervix and anus. While the value of vaccination for prevention of OPC and possibly as an adjuvant treatment is still an open question, evidence to date supports the possibility that HPV vaccination may prove to be effective in reducing the incidence of this malignancy.

Determining rubella immunity in pregnant Alberta women 2009-2012

Rubella IgG levels for 157,763 pregnant women residing in Alberta between 2009 and 2012 were analyzed. As there have been no reported cases of indigenous rubella infection in Canada since 2005, there has been a lack of naturally acquired immunity, and the current prenatal population depends almost entirely on vaccine induced immunity for protection. Rubella antibody levels are significantly lower in younger maternal cohorts with 16.8% of those born prior to universal vaccination programs (1971-1980), and 33.8% of those born after (1981-1990) having IgG levels that are not considered protective (<15 IU/mL). Analysis across pregnancies showed only 35.0% of women responded with a 4-fold increase in antibody levels following post-natal vaccination. Additionally, 41.2% of women with antibody levels <15 IU/mL had previously received 2 doses of rubella containing vaccine. These discordant interpretations generate a great deal of confusion for laboratorians and physicians alike, and result in significant patient follow-up by Public Health teams. To assess the current antibody levels in the prenatal population, latent class modeling was employed to generate a two class fit model representing women with an antibody response to rubella, and women without an antibody response. The declining level of vaccine-induced antibodies in our population is disconcerting, and a combined approach from the laboratory and Public Health may be required to provide appropriate follow up for women who are truly susceptible to rubella infection.

Prenatal characteristics of infants with a neuronal migration disorder: a national-based study

The development of the central nervous system is complex and includes dorsal and ventral induction, neuronal proliferation, and neuronal migration, organization, and myelination. Migration occurs in humans in early fetal life. Pathogenesis of malformations of the central nervous system includes both genetic and environmental factors. Few epidemiological studies have addressed the impact of prenatal exposures. All infants born alive and included in the Swedish Medical Birth Register 1980–1999 were included in the study. By linkage to the Patient Register, 820 children with a diagnosis related to a neuronal migration abnormality were identified. Through copies of referrals for computer tomography or magnetic resonance imaging of the brain, the diagnosis was confirmed in 17 children. Median age of the mothers was 29 years. At the start of pregnancy, four out of 17 women smoked. Almost half of the women had a body mass index that is low or in the lower range of average. All infants were born at term with normal birth weights. Thirteen infants had one or more concomitant diseases or malformations. Two infants were born with rubella syndrome. The impact of low maternal body mass index and congenital infections on neuronal migration disorders in infants should be addressed in future studies.

Rubella revisited: where are we on the road to disease elimination in Central Europe?

Rubella is a contagious viral disease with few complications except when contracted by pregnant women. Rubella infection in pregnancy can result in miscarriage, stillbirth or an infant born with congenital rubella syndrome (CRS) which comprises deafness, heart disease, cataracts and other permanent congenital manifestations. Clinical diagnosis of rubella is difficult due to overlapping symptoms with many other diseases and confirmation of rubella is not possible without laboratory testing. Effective vaccination programmes are critical to the elimination of rubella and prevention of CRS. Such programmes have been successful in several countries in Europe and around the world. However, rubella outbreaks still occur due to suboptimal vaccine coverage and in the past 10 years rubella has been reported in Central European countries such as Romania and Poland. Over the past decade the elimination of rubella and prevention of congenital rubella infection in Europe has been a high priority for the WHO European Regional Office. In 2010 the WHO regional committee for Europe renewed its commitment to the elimination of rubella and prevention of CRS with a new target of 2015. This paper examines the current situation for rubella and CRS in Central Europe and describes the different rubella vaccination programmes in the region. The Central European Vaccination Advisory Group (CEVAG) recommends that two doses of measles, mumps and rubella vaccine, MMR, should be given to all children. The first dose should be given between 12 and 15 months of age. The second dose can be given between the ages of 21 months and 13 years with the exact age of administration of the second dose depending on the situation specific to each country. All suspected rubella cases should be laboratory-confirmed and monitoring systems to detect and investigate cases of CRS should be strengthened.

Position paper--HPV and the primary prevention of cancer; improving vaccine uptake by paediatricians

A large proportion of sexually active adults are infected with the human papillomaviruses (HPVs). Although largely asymptomatic, some types of HPVs (HPV-16, HPV-18) which infect the genitalia are known to cause cancers, including cervical cancer. Cervical cancer is an important public health concern and is the second most clinically important cancer to breast cancer in women aged 15-44 years. Until recently, cervical cancer strategies focussed on screening. However, as adolescents become sexually active at a much younger age, the focus is on the use of vaccination as an effective measure to prevent progression of HPV infection to cancer. HPV is also involved in the aetiology of cancers of the anus, vagina, vulva and penis as well as genital warts and laryngeal papillomatosis in young children. Primary prevention through vaccination is now possible in Europe using either the quadrivalent HPV vaccine, Gardasil® (Sanofi Pasteur MSD), or the bivalent HPV vaccine, Cervarix® (GSK), which are both highly immunogenic, with their effects persisting for at least 5 years. HPV vaccines are well tolerated, with serious vaccine-related events occurring in less than 0.1% of patients for both vaccines. Here, we review the possibilities for utilising vaccination programmes alongside current cervical cancer screening in comprehensive cervical cancer prevention programmes. The European Academy of Paediatrics Scientific Working Group on Vaccination concluded that the use of HPV vaccines will have a significant impact in primary prevention of cancers and other HPV-related disease.

Phylogenetic analysis of rubella viruses involved in congenital rubella infections in France between 1995 and 2009

Rubella is an acute infectious disease that normally has a mild clinical course. However, infections during pregnancy, especially before week 12 of gestation (WG), can cause severe birth defects known as congenital rubella syndrome (CRS). The aim of this study was to perform genotyping and molecular characterization of rubella viruses involved in congenital infections in France over the past 15 years (1995 to 2009). Amniotic fluid (AF) specimens (n = 80) from pregnant women with congenital rubella infections (CRI) before week 20 of gestation, and a few other samples available from children/newborns with CRS (n = 26), were analyzed. The coding region of the rubella virus E1 gene was amplified directly from clinical specimens by reverse transcriptase PCR, and the resulting DNA fragments were sequenced. Sequences were assigned to genotypes by phylogenetic analysis with rubella virus reference sequences. Sufficient E1 gene sequences were obtained from 56 cases. Phylogenetic analysis of the sequences showed that at least five different genotypes (1E, 1G, 1B, 2B, and 1h) were present in France and were involved in congenital infections, with a strong predominance of genotype 1E (87%). This is one of the very few comprehensive studies of rubella viruses involved in CRI. The results indicated that over the past 15 years, multiple introductions of the dominant genotype E caused most of the CRI cases in France. A few sporadic cases were due to other genotypes (1B, 1G, 1h, 2B).

HPV vaccine: Cervarix

IMPORTANCE OF THE FIELD

Cervical cancer is a major cause of morbidity and mortality worldwide and is common in relatively young women. Cervical screening programs, while successful if properly carried out, are difficult and expensive to implement, and offer secondary, not primary prevention. Vaccination against the human papillomavirus (HPV), which is the major cause of cervical cancer, is a significant step forward.

AREAS COVERED IN THIS REVIEW

The data on Cervarix, the GSK HPV vaccine, are reviewed and placed in the context of HPV vaccination as a whole. A literature review using PubMed listed publications and official product websites has been carried out.

WHAT THE READER WILL GAIN

The reader will gain an understanding of the issues involved in HPV vaccination and of the data to date.

TAKE HOME MESSAGE

Cervarix has been shown to have high efficacy against disease associated with both HPV-16 and HPV-18. Its antibody response profile allows for optimism regarding the duration of immunity. The fact that it is a virus-like particle, rather than a live-virus vaccine, is reassuring regarding safety, as are the reasonably extensive safety data for the vaccine preparation so far accrued. Cross protection against oncogenic non-vaccine HPV types, in particular HPV-45, may be important in the prevention of cervical adenocarcinoma, which is currently not well served by screening.

Serum levels of rubella-specific antibodies in Swedish women following three decades of vaccination programmes

In Sweden, more than 30 years after the introduction of vaccination for 12-year-old girls and post-partum mothers against rubella and 22 years after the introduction of routine MMR vaccination for all children at the ages of 18 months and 12 years, we have evaluated the rubella IgG activity in antenatal sera. 95.8% (39,890/41,637) of all women had anti-rubella IgG levels >or=10IU/mL. Levels <10IU/mL were more frequent in certain subcohorts: 8.2% (153/1870) of the Swedish women born after the introduction of the programme of childhood vaccination, 7.7% (616/8025) of women born outside the Nordic countries and 10.2% (118/1155) of recent immigrants and refugees to Sweden. In order to attain the goal of protecting the unborn, we propose alternative strategies to be evaluated: routine screening for rubella immunity prior to the first pregnancy, offering individuals with uncertain immunity a booster dose, and/or routine administration of an additional dose of MMR vaccine to all young adults before they leave the educational system.

Human papillomavirus vaccination in the United Kingdom: what about boys?

In September 2008 the UK Department of Health initiated a human papillomavirus (HPV) immunisation programme for girls aged 12-13 for prevention of cervical cancer, which is most often caused by two HPV types. An important question, yet to be addressed, is whether boys should also be vaccinated. Men also get HPV and transmit it sexually, not just women. Certain HPV types are associated with genital warts, which have significant morbidity, and with difficult to treat non-cervical malignancies, including vulval, penile, anal and oro-pharyngeal cancer, which are best prevented through vaccination. Moreover, increased persistence of HPV infection is associated with HIV infection. A review of the literature and evidence from modelling suggest that vaccinating boys would increase vaccination impact and may be necessary to achieve herd immunity targets. Excluding boys sends the wrong message that girls and women alone are responsible for sexual health. Although protective efficacy of the vaccine in men has not yet been fully established, the rationale for vaccinating boys as well as girls at an early age is strong, assuming efficacy is established. Meanwhile, provision of the quadrivalent vaccine should become UK policy, in order to include protection against genital warts, the argument for which is strengthened if boys are also vaccinated.

Multiple sclerosis incidence in the era of measles-mumps-rubella mass vaccinations

BACKGROUND

Viral childhood infections may be involved in the multiple sclerosis (MS) pathogenesis. Following national Swedish vaccination programs, measles sharply declined in the 1970s, and measles, mumps, and rubella were virtually eliminated in cohorts born from 1981.

OBJECTIVES

To examine whether the vaccination induced reduction in these infections influences the MS incidence. In addition, the public health aspect justified an early evaluation of beneficial as well as harmful effects of mass vaccinations.

MATERIALS AND METHODS

From an incidence material of 534 MS patients, born 1959-1990, we selected one unvaccinated cohort and four cohorts, each corresponding to a vaccination program (MS patients = 251).

RESULTS

With the ability to detect a decrease by 30-35%, and an increase by 37-48% in the MS incidence in the first three cohorts, we found no vaccination related MS incidence changes. The background MS incidence showed a significant gradual age dependent increase.

CONCLUSIONS

While the present follow-up provided limited power in the last cohort, there is no evidence as yet that the radical decline in three viral infections influenced the MS incidence. However, the increasing background MS incidence of unknown cause may have concealed a reduction in MS risk associated with mass vaccinations.

Initial lessons learned in HPV vaccination

In the recent period following the approval of the first vaccine targeted against human papillomavirus, it is imperative that we re-evaluate the past, present, and future of cervical cancer prevention. It is clear that the subject of vaccinating young women against a sexually transmitted infection has incited a candid debate among all groups involved. Therefore, we must make the most appropriate and accurate information available to the public and medical communities. The development of vaccines targeted against oncogenic human papillomavirus (HPV) types has made it possible to eliminate approximately 70% of all invasive cervical cancers in women worldwide. However, knowledge about HPV infection and cervical cancer, as well as the need to vaccinate against oncogenic HPV infection, is still lacking among women and physicians. This deficiency could be a key reason why some parents continue to have reservations about vaccinating their daughters. In order for HPV vaccination programs to be highly successful, multiple barriers must be overcome. Review of lessons learned to date has demonstrated that continued tailored and targeted educational and awareness initiatives are required for healthcare professionals, media, patients, and parents. This article also examines the impact of the HPV vaccination awareness campaign on media and public policy dynamics.

Programmatic issues in the implementation of an HPV vaccination program to prevent cervical cancer

BACKGROUND

Cervical cancer remains an important health problem even in countries with effective cervical screening programs. HPV vaccines offer great potential for primary prevention of cervical cancer and other HPV-related diseases.

PERSPECTIVES

Eventual implementation of an HPV vaccination program raises several key issues, including universal vs. targeted vaccinations, the age and gender of vaccine recipients, the acceptability of this vaccine to health care providers, adolescents, and parents, and the effect of this vaccine on cervical cancer screening. These issues were explored among symposium attendees during an interactive question-and-answer session using computerized voting pads.

CONCLUSIONS

Preventative HPV vaccination programs should ideally be executed universally in both women and men with an emphasis on children and adolescents prior to their first sexual experience. Parent education on HPV disease and vaccine efficacy and safety will be critical to the acceptability of HPV vaccination for their children. HPV vaccination will not eliminate the need for Pap screening. Further research will be needed to develop rational and cost-effective cervical surveillance programs for women protected by HPV vaccines.

Overview of the clinical development and results of a quadrivalent HPV (types 6, 11, 16, 18) vaccine

BACKGROUND

Human papillomaviruses (HPVs) play an obligatory role in cervical cancer development. Thus, immunization of women using a prophylactic vaccine against the most common high-oncogenic risk types (e.g., HPV 16 and 18) and HPV 6 and 11, which contribute to development of low-grade cervical lesions and cause most anogenital warts, represents a logical primary prevention strategy.

PERSPECTIVES

At the time of licensure, Phase II/Phase III studies showed that administration of a quadrivalent HPV (types 6, 11, 16, 18) vaccine to young women (16 to 26 years) naïve to the vac- cine HPV types resulted in 100% efficacy against HPV 16- and 18-related precancerous cervical lesions, 100% efficacy against HPV 16- and 18-related high-grade vulvar/vaginal neoplasias, 95% efficacy against HPV 6, 11, 16, or 18-related cervical intraepithelial neoplasia/adenocarcinoma in situ, and 99% efficacy against HPV 6, 11, 16, or 18-related genital lesions. The quadrivalent HPV vaccine is highly immunogenic in adolescent males and females, and long-term follow up of young women did not detect evidence of waning immunity through 5 years.

CONCLUSIONS

The quadrivalent vaccine is generally well tolerated. The efficacy and safety of the quadrivalent vaccine is continuing to be investigated in young men and mid-adult women. Nordic cancer registries are providing ongoing long-term pharmacovigilance.

Comparison of four methods using throat swabs to confirm rubella virus infection

Laboratory tests are essential for confirming sporadic cases and outbreaks of rubella. Detection of rubella virus is often necessary to confirm rubella cases and to identify specimens to be used to characterize wild-type rubella viruses. The sensitivities of four methods for detecting rubella virus infection using throat swabs, which had been collected in Henan and Anhui provinces in China, were evaluated. The methods used were reverse transcription (RT)-PCR followed by Southern hybridization using RNA extracted directly from clinical specimens, virus growth in tissue culture followed by virus detection by RT-PCR, low-background immunofluorescence in infected tissue culture cells using monoclonal antibodies to the structural proteins of rubella virus, and a replicon-based method of detecting infectious virus. Among these four methods, direct RT-PCR followed by hybridization was the most sensitive method; the replicon-based method was the least difficult to perform.

Rubella immune status of indigenous and immigrant pregnant women in Catalonia, Spain

BACKGROUND

The objective of the study was to determine the prevalence of rubella antibodies in representative samples of pregnant women in Catalonia.

METHODS

A representative sample of pregnant women in Catalonia was obtained by random sampling by clusters (hospitals with maternity units) stratified by provinces. Blood was obtained from the umbilical cord at childbirth in 1538 women (of whom 308 were immigrants) and was tested for rubella antibodies by ELISA (Enzime-linked immunosorbent assay).

RESULTS

The global prevalence of antibodies was 93.4% [95% confidence interval (CI): 93.3-93.5] and was significantly higher in indigenous women (94.9;95%CI:93.3-95.9) compared with immigrants [89.0; 95%CI: 85.5-92.5 (P<0. 0001)] with crude Odds ratio (OR) of 2.15 (95%CI: 1.40-3.32).The prevalence was higher in women living in rural habitats (97%) and those in higher social classes (96.3%); OR 2.54 (95%CI: 1.22-5.30) and 2.17 (95%CI: 1.24-3.81), respectively.

CONCLUSION

Fertile female immigrants from countries with no vaccination or where vaccination coverage is low should be actively approached for vaccination to reduce the risk of infection and congenital rubella.

Comparison of the immunogenicity and reactogenicity of a prophylactic quadrivalent human papillomavirus (types 6, 11, 16, and 18) L1 virus-like particle vaccine in male and female adolescents and young adult women

OBJECTIVE

Prophylactic vaccination of 16- to 23-year-old females with a quadrivalent human papillomavirus (types 6, 11, 16, 18) L1 virus-like particle vaccine has been shown to prevent type-specific human papillomavirus infection and associated clinical disease. We conducted a noninferiority immunogenicity study to bridge the efficacy findings in young women to preadolescent and adolescent girls and boys, who represent a primary target for human papillomavirus vaccination.

METHODS

We enrolled 506 girls and 510 boys (10-15 years of age) and 513 females (16-23 years of age). Participants were vaccinated on day 1, at month 2, and at month 6, and serology testing was performed on day 1 and at months 3 and 7 on blinded samples. Neutralizing antibody concentrations were determined using type-specific immunoassays and summarized as geometric mean titers and seroconversion rates. Vaccine tolerability also was assessed.

RESULTS

By month 7, seroconversion rates were > or = 99% for all 4 human papillomavirus types in each group. By month 7, compared with women, anti-human papilloma virus geometric mean titers in girls or boys were noninferior and were 1.7- to 2.7-fold higher. Most (> 97%) injection-site adverse events were mild to moderate in intensity. Significantly more boys (13.8%) and girls (12.8%) than women (7.3%) reported fevers > or = 37.8 degrees C within 5 days of vaccination. Most (96.4%) fevers were mild (< 39 degrees C).

CONCLUSIONS

Noninferior immunogenic responses to all 4 human papillomavirus types in the quadrivalent vaccine permit the bridging of efficacy data that were generated in young women to girls. The results in boys lend support for the implementation of gender-neutral human papillomavirus vaccination programs. This vaccine generally was well tolerated.

The epidemiological profile of rubella and congenital rubella syndrome in the United States, 1998-2004: the evidence for absence of endemic transmission

In 1969, the United States established its national rubella vaccination program. With the success of the program, 32 years later, reports of rubella reached record low numbers. To assess the achievement of elimination of rubella and congenital rubella syndrome (CRS) in the United States, 7 epidemiological criteria were used. Rubella cases reported to the National Notifiable Diseases Surveillance System from 1998 through 2004 and CRS cases reported to the National Congenital Rubella Syndrome Registry from 1998 through 2004 were analyzed. During 1998-2000, the median number of reported rubella cases was 272, whereas, during 2001-2004, the median number reported was 13. The incidence of rubella decreased significantly, from 0.1/100,000 population in 1998 to 0.005/100,000 population in 2004. Since 2001, 5 infants with CRS have been reported--3 were born in 2001, 1 was born in 2003, and 1 was born in 2004. The epidemiological evidence strongly supports the claim that rubella is no longer endemic in the United States. To prevent future rubella outbreaks and CRS cases, current strategies must be maintained.

Modelling the effect of a booster vaccination on disease epidemiology

Despite the effectiveness of vaccines in dramatically decreasing the number of new infectious cases and severity of illnesses, imperfect vaccines may not completely prevent infection. This is because the immunity afforded by these vaccines is not complete and may wane with time, leading to resurgence and epidemic outbreaks notwithstanding high levels of primary vaccination. To prevent an endemic spread of disease, and achieve eradication, several countries have introduced booster vaccination programs. The question of whether this strategy could eventually provide the conditions for global eradication is addressed here by developing a seasonally-forced mathematical model. The analysis of the model provides the threshold condition for disease control in terms of four major parameters: coverage of the primary vaccine; efficacy of the vaccine; waning rate; and the rate of booster administration. The results show that if the vaccine provides only temporary immunity, then the infection typically cannot be eradicated by a single vaccination episode. Furthermore, having a booster program does not necessarily guarantee the control of a disease, though the level of epidemicity may be reduced. In addition, these findings strongly suggest that the high coverage of primary vaccination remains crucial to the success of a booster strategy. Simulations using estimated parameters for measles illustrate model predictions.

Rubella, rubeola, and mumps in pregnant women: susceptibilities and strategies for testing and vaccinating

OBJECTIVE

To estimate rubella, rubeola, and mumps (MMR) susceptibilities in pregnant women and determine the percentage not immune to rubeola or mumps, depending on rubella immunity status. A secondary objective was to assess costs of vaccination and testing programs aimed at eliminating these viral susceptibilities to determine an optimal strategy.

METHODS

This was an observational study of women presenting for prenatal care. All women had MMR antibody titers measured. Viral susceptibilities were compared by age, gravidity, parity, and recall of vaccine booster. A logistic regression was performed to assess for predictors of MMR immunity. A cost comparison of different screening and vaccination strategies was performed.

RESULTS

Overall, 91 (9.4%) women were susceptible to rubella, 161 (16.5%) to rubeola, and 159 (16.3%) to mumps. Three hundred seventeen (32.6%) were susceptible to at least 1 virus, whereas only 17 (1.7%) were susceptible to all 3. Of the women who were immune to rubella, a large percentage were not immune to either rubeola or mumps (n = 226, 25.6%). Only 74.2% of women who knew they had a booster vaccine were immune to all components of the MMR vaccine. Receiving a booster was predictive of immunity to all 3 viruses. A cost analysis demonstrated that broader screening strategies are more comprehensive and more expensive.

CONCLUSION

The current screening and vaccine program has left many reproductive-aged women susceptible to rubella, rubeola, and mumps infections. Perhaps a more comprehensive viral screening program is needed to ensure immunity.

Vaccines against cervical cancer

Cervical cancer and precancerous lesions of the genital tract are a major threat to women's health worldwide. Although the introduction of screening tests to detect cervical cancer and its precursor lesions has reduced overall cervical cancer rates in the developed world, the approach was largely unsuccessful for developing countries, primarily due to a lack of appropriate infrastructures and high costs. Annually, 470,000 cervical cancer cases are diagnosed worldwide, of which 80% occur in developing countries. Despite advances in treatment of cervical cancer, approximately half of the women afflicted with the disease will die. Over 20 years of dedicated research has provided conclusive evidence that a subset of human papillomaviruses are the aetiological agents for cervical cancer. Finding a viral origin for this disease provided the basis to fight cervical cancer using prophylactic or therapeutic vaccination. Both vaccine approaches are reviewed here, with an emphasis on recent clinical data.

Human Papillomavirus Vaccines and Prevention of Cervical Cancer

Cervical cancer and precancerous cervical lesions constitute a major problem in women's health. Every year 470,000 cases of cervical cancer are diagnosed worldwide, and about half the women afflicted will die. In the United States alone, approximately 14,000 cases of cervical cancer are diagnosed each year despite the availability of screening and access to high-quality gynecological care. With the confirmation that cervical cancer is caused by an infectious agent, human papillomavirus, the possibility of fighting this disease with either prophylactic or therapeutic vaccination arose. This review describes advances in vaccine development and very promising first results for prophylactic vaccination against cervical cancer.

Rubella eradication

The virulence of rubella virus for the fetus was fully defined between 1963 and 1965 when an epidemic of rubella occurred in Europe and the US, followed by a wave of damaged babies. Attenuated live virus vaccines were developed in our and other laboratories and their use has already considerably changed the epidemiology of rubella. Nevertheless, only about half of the world's countries vaccinate against rubella. We argue for the combination of rubella vaccine with measles vaccine in all campaigns for the control of measles, and will discuss the strategies by which congenital rubella syndrome could be eradicated at little additional cost.

Duration of rubella immunity induced by two-dose measles, mumps and rubella (MMR) vaccination. A 15-year follow-up in Finland

A national two-dose vaccination program with a combined measles, mumps and rubella (MMR-II) vaccine was introduced in Finland, in 1982, immunizing children at the ages of 14-18 months and 6 years. Antibody levels were determined from serial samples from a group of originally 350 children during 15 years. The latest samples were taken 15.5 years after the first vaccination and 70% of the children could still be reached. The aim of this study was to determine the kinetics of rubella antibodies induced by the MMR-II vaccine in these individuals. Rubella antibodies were analyzed from three different cohorts: Group I seronegative children (n=166) vaccinated at 14-18 months and 6 years, Group II seronegative children (n=139) and Group III seropositive children (n=16) vaccinated at 6 and 11-13 years. Samples collected 0-9 years after vaccination were analyzed by hemolysis-in-gel (HIG) and later samples by enzyme immunoassay (EIA) techniques. The primary vaccination induced 100% seropositivity in vaccinees with a mean zone diameter of 10 (+/-1.3), 10.2 (+/-1.1) and 11.5 (+/-0.9) mm, in Groups I, II and III, respectively. The seropositivity rate was still high at 15 years, 99%, 100% and 100% with the geometric mean titer 23, 46 and 105 IU/ml, respectively. At 15 years, antibody levels <15 IU/ml which is the suggested protective level, were found in 31, 9 and 0% of children in Groups I, II and III, respectively. Because almost a third of the individuals in Group I now, at the age of 17 years, had low levels of rubella antibodies, it is possible that rubella infections may re-emerge during pregnancy. A careful surveillance including serological follow-up is therefore very important.

Increase in congenital rubella occurrence after immunisation in Greece: retrospective survey and systematic review

OBJECTIVE

To describe the events leading to the epidemic of congenital rubella syndrome in Greece in 1993 after a major rubella epidemic.

DESIGN

Retrospective survey and systematic review.

SETTING

Greece (population 10 million), 1950-95.

SUBJECTS

Children, adolescents, and women of childbearing age.

RESULTS

Around 1975 in Greece the measles, mumps, and rubella vaccine started being given to boys and girls aged 1 year without policies to attain high vaccination coverage and to protect adolescents and young women. During the 1980s, vaccination coverage for rubella remained consistently below 50%, and the proportion of pregnant women susceptible to rubella gradually increased. In 1993 the incidence of rubella in young adults was higher than in any previous epidemic year. The epidemic of congenital rubella that followed, with 25 serologically confirmed cases (24.6 per 100 000 live births), was probably the largest such epidemic in Greece after 1950.

CONCLUSIONS

With low vaccination coverage, the immunisation of boys and girls aged 1 year against rubella carries the theoretical risk of increasing the occurrence of congenital rubella. This phenomenon, which has not been previously reported, occurred in Greece.