Dual RNA-Seq Enables Full-Genome Assembly of Measles Virus and Characterization of Host-Pathogen Interactions

Measles virus (MeV) has a negative-sense 15 kb long RNA genome, which is generally conserved. Recent advances in high-throughput sequencing (HTS) and Dual RNA-seq allow the analysis of viral RNA genomes and the discovery of viral infection biomarkers, via the simultaneous characterization of the host transcriptome. However, these host-pathogen interactions remain largely unexplored in MeV infections. We performed untargeted Dual RNA-seq in 6 pharyngeal and 6 peripheral blood mononuclear cell (PBMCs) specimens from patients with MeV infection, as confirmed via routine real-time PCR testing. Following optimised DNase treatment of total nucleic acids, we used the pharyngeal samples to build poly-A-enriched NGS libraries. We reconstructed the viral genomes using the pharyngeal datasets and we further conducted differential expression, gene-ontology and pathways enrichment analysis to compare both the pharyngeal and the peripheral blood transcriptomes of the MeV-infected patients vs. control groups of healthy individuals. We obtained 6 MeV genotype-B3 full-genome sequences. We minutely analyzed the transcriptome of the MeV-infected pharyngeal epithelium, detecting all known viral infection biomarkers, but also revealing a functional cluster of local antiviral and inflammatory immune responses, which differ substantially from those observed in the PBMCs transcriptome. The application of Dual RNA-seq technologies in MeV-infected patients can potentially provide valuable information on the virus genome structure and the cellular innate immune responses and drive the discovery of new targets for antiviral therapy.

Long time immunogenicity of measles vaccine in the vaccination era: An open question

After WHO European Region determined the 2005 - 2010 Strategic Plan for measles elimination, the number of reported measles cases in Europe fell dramatically. This decrease is related to the vaccination strategy carried out by European countries. This extensive immunization strategy changes the epidemiological patter and could influence the effectiveness and the long-time immunogenicity of the vaccine. To evaluate the long-time immunogenicity of the measles vaccine in the vaccination era, a pilot study among vaccinated blood donors in Apulia was designed. Of 174 enrolled patients, 93.7% presented an anti-measles IgG titer positive. GMT seems to increase by age (p = 0.001). The GMT seems to increase by age and this could be related to the exposition to natural boosters, that was more probable before the beginning of universal mass vaccination against measles. Future studies have to focus the correlation between GMT and age.

A global perspective of vaccination of healthcare personnel against measles: systematic review

Measles transmission has been well documented in healthcare facilities. Healthcare personnel who are unvaccinated and who lack other evidence of measles immunity put themselves and their patients at risk for measles. We conducted a systematic literature review of measles vaccination policies and their implementation in healthcare personnel, measles seroprevalence among healthcare personnel, measles transmission and disease burden in healthcare settings, and impact/costs incurred by healthcare facilities for healthcare-associated measles transmission. Five database searches yielded 135 relevant articles; 47 additional articles were found through cross-referencing. The risk of acquiring measles is estimated to be 2 to 19 times higher for susceptible healthcare personnel than for the general population. Fifty-three articles published worldwide during 1989-2013 reported measles transmission from patients to healthcare personnel; many of the healthcare personnel were unvaccinated or had unknown vaccination status. Eighteen articles published worldwide during 1982-2013 described examples of transmission from healthcare personnel to patients or to other healthcare personnel. Half of European countries have no measles vaccine policies for healthcare personnel. There is no global policy recommendation for the vaccination of healthcare personnel against measles. Even in countries such as the United States or Finland that have national policies, the recommendations are not uniformly implemented in healthcare facilities. Measles serosusceptibility in healthcare personnel varied widely across studies (median 6.5%, range 0-46%) but was consistently higher among younger healthcare personnel. Deficiencies in documentation of two doses of measles vaccination or other evidence of immunity among healthcare personnel presents challenges in responding to measles exposures in healthcare settings. Evaluating and containing exposures and outbreaks in healthcare settings can be disruptive and costly. Establishing policies for measles vaccination for healthcare personnel is an important strategy towards achieving measles elimination and should be a high priority for global policy setting groups, governments, and hospitals.

Post-exposure passive immunisation for preventing measles

BACKGROUND

Measles outbreaks continue to occur in countries with high vaccination coverage. Passive immunisation is generally considered to prevent measles in someone who is not immune and has been exposed to infection. Estimates of effectiveness have varied and no minimum effective dose has been determined.

OBJECTIVES

To assess the effectiveness and safety of intramuscular injection or intravenous infusion of immunoglobulins (passive immunisation) for preventing measles when administered to exposed susceptible people before the onset of symptoms.

SEARCH METHODS

We searched CENTRAL (2013, Issue 7), MEDLINE (1946 to July week 5, 2013), CINAHL (1981 to August 2013) and EMBASE (1974 to August 2013).

SELECTION CRITERIA

We included randomised controlled trials (RCTs), quasi-RCTs and prospective, controlled (cohort) studies if: participants were susceptible and exposed to measles, polyclonal immunoglobulins derived from human sera or plasma were administered intramuscularly or intravenously as the only intervention in at least one group and the number of subsequent measles cases was measured. We excluded studies of other sources of immunoglobulins.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and critically appraised the included studies. We attempted to contact study authors for missing information. We described the results of studies not included in meta-analyses.

MAIN RESULTS

We included one RCT, two quasi-RCTs and 10 cohort studies (3925 participants). No studies were rated as low risk of bias for all criteria. Critical appraisal was constrained by a lack of information in most studies. The overall quality of the evidence was moderate.Seven studies (1432 participants) assessed cases of measles after immunoglobulin versus no treatment. Heterogeneity was explained by subgrouping according to the blood product used as an approximation of dose of immunoglobulin. When given within seven days of exposure, immunoglobulins were effective at preventing measles: gamma globulin (risk ratio (RR) 0.17, 95% confidence interval (CI) 0.08 to 0.36), convalescent serum (RR 0.21, 95% CI 0.15 to 0.29 to RR 0.49, 95% CI 0.44 to 0.54) and adult serum (RR 0.52, 95% CI 0.45 to 0.59). The differences in the effectiveness of different blood products were supported by studies not included in the meta-analysis and by two studies (702 participants) that found gamma globulin more effective than serum (RR 0.56, 95% CI 0.46 to 0.69).Based on three studies (893 participants) immunoglobulin was effective at preventing death due to measles compared to no treatment (RR 0.24, 95% CI 0.13 to 0.44).Two studies included measles vaccine alone among the intervention groups. Meta-analysis could not be undertaken. Both studies suggested the vaccine was more effective than gamma globulin.No serious adverse events were observed in any of the included studies, although reporting of adverse events was poor overall. Non-serious adverse events included transient fever, rash, muscle stiffness, local redness and induration.

AUTHORS' CONCLUSIONS

Passive immunisation within seven days of exposure is effective at preventing measles, with the risk for non-immune people up to 83% less than if no treatment is given. Given an attack rate of 45 per 1000 (per the control group of the most recent included study), gamma globulin compared to no treatment has an absolute risk reduction (ARR) of 37 per 1000 and a number needed to treat to benefit (NNTB) of 27. Given an attack rate of 759 per 1000 (per the attack rate of the other included study assessing gamma globulin), the ARR of gamma globulin compared to no treatment is 629 and the NNTB is two.It seems the dose of immunoglobulin administered impacts on effectiveness. A minimum effective dose of measles-specific antibodies could not be identified.Passive immunisation is effective at preventing deaths from measles, reducing the risk by 76% compared to no treatment. Whether the benefits of passive immunisation vary among subgroups of non-immune exposed people could not be determined.Due to a paucity of evidence comparing vaccine to passive immunisation, no firm conclusions can be drawn regarding relative effectiveness.The included studies were not specifically designed to detect adverse events.Future research should consider the effectiveness of passive immunisation for preventing measles in high-risk populations such as pregnant women, immunocompromised people and infants. Further efforts should be made to determine the minimum effective dose of measles-specific antibodies for post-exposure prophylaxis and the relative effectiveness of vaccine compared to immunoglobulin.

[Progress in the elimination of measles and rubella in the WHO European Region]

Substantial progress has been made in the World Health Organization (WHO) European Region toward reaching the goal of measles and rubella elimination. We analyzed the surveillance data of 2012 on measles and rubella for age-group, diagnosis confirmation status (clinical, laboratory-confirmed and epidemiologically linked), vaccination status, and measles-related deaths. For 2012, there were 23,871 measles cases and 29,361 rubella cases reported in the region, mostly among unvaccinated persons. Almost one in three patients with measles and one in five patients with rubella were aged 20 years and older. In a few countries, widespread outbreaks or indigenous transmission of measles persisted in 2012. While most countries in the region have controlled rubella, a small number still reported a high incidence and several outbreaks. Therefore, more efforts are required to achieve the goal of eliminating measles and rubella in the WHO European Region by 2015, particularly in high-incidence countries. The WHO measles and rubella elimination plan stipulates that all countries should achieve and maintain the required high vaccination coverage while conducting high-quality surveillance.

[Hot spot: epidemiology of measles and rubella in Germany and the WHO European region]

The elimination of measles and rubella by 2015 is an important goal set by the World Health Organization European Region (WHO/Europa). Since 1991, the incidence of measles in WHO/Europa declined owing to routine childhood vaccination and supplementary immunization activities in the region. However, in many countries of Western Europe elimination of measles and rubella remains a challenge, and every year there are outbreaks with partly long-lasting transmission chains and dissemination of the virus internationally. In Germany, outbreaks occur because of the high proportion of susceptible individuals in specific population groups. In 2011, over 1,600 cases were reported (19.7 per 1,000,000 inhabitants, data from the Robert Koch Institute) whereas in 2012 only 167 cases were reported to the Robert Koch Institute (2 per 1,000,000 inhabitants). It is unclear whether the declining trend will continue in the following years due to improved vaccination coverage or whether number of cases will rise again because of the accumulation of susceptible groups. In Germany, there are currently no representative, country-wide data on rubella; however, data from the eastern federal states provide important epidemiological insights. Outbreaks are seldom reported, but statutory notification of rubella and congenital rubella syndrome was implemented in March 2013. As a result, it will be possible to better assess the epidemiology of rubella in Germany, although a considerable underreporting of rubella cases is anticipated.

Measles outbreak in Europe: susceptibility of infants too young to be immunized

As women vaccinated against measles transfer low amounts of antibodies, an increasing number of infants lack early protection through maternal antibodies until being immunised themselves. This paper reviews the literature on disease burden of measles in the population too young to be immunized according to the respective national recommendations during recent outbreaks in EU and EEA/EFTA countries. In addition, specific control strategies adopted to protect this young population are reviewed. Pubmed, Unbound Medline, Web of Knowledge and the Eurosurveillance database were searched using MESH terms: measles and epidemiology, measles and infants, prevalence of measles, measles and outbreaks and measles and epidemic. Additionally, data from Euvac.net and ECDC were consulted. Databases were searched from January 2001 to September 2011. Fifty-three papers were included in the analysis. The percentage of all measles cases during outbreaks affecting young infants ranged from 0.25% to 83.0%. Specific control strategies were adopted: e.g. administration of the first or second vaccine dose earlier than recommended. Infants younger than 12 months are often involved in measles outbreaks, and advancing the first vaccine dose could reduce the burden of disease. However, immunization before 9 months of age is not systematically recommended because of dysmature humoral immune responses of infants. High coverage and timely administration of the recommended series of vaccines are the most important measures to decrease measles incidence and measles circulation and protect vulnerable infants from infection.

Research priorities for global measles and rubella control and eradication

In 2010, an expert advisory panel convened by the World Health Organization to assess the feasibility of measles eradication concluded that (1) measles can and should be eradicated, (2) eradication by 2020 is feasible if measurable progress is made toward existing 2015 measles mortality reduction targets, (3) measles eradication activities should occur in the context of strengthening routine immunization services, and (4) measles eradication activities should be used to accelerate control and elimination of rubella and congenital rubella syndrome (CRS). The expert advisory panel also emphasized the critical role of research and innovation in any disease control or eradication program. In May 2011, a meeting was held to identify and prioritize research priorities to support measles and rubella/CRS control and potential eradication activities. This summary presents the questions identified by the meeting participants and their relative priority within the following categories: (1) measles epidemiology, (2) vaccine development and alternative vaccine delivery, (3) surveillance and laboratory methods, (4) immunization strategies, (5) mathematical modeling and economic analyses, and (6) rubella/CRS control and elimination.

Comparative coverage of supplementary and universally recommended immunizations in children at 24 months of age

BACKGROUND

The introduction of pneumococcal and meningococcal group C conjugate vaccinations as supplementary (a new category in Swiss immunization recommendations) to universally recommended vaccinations in 2006 prompted this study to investigate their acceptance.

METHODS

The study was performed in 24-month-old healthy children born in the Geneva or Basel areas in Switzerland between January and April 2007. After informed consent had been obtained from caregivers (for this particular study in Basel and in general for providing immunization data in Geneva on an ongoing basis), all universally recommended and supplementary vaccinations administered by ≤24 months of age were analyzed for completeness and timeliness according to set definitions. Sample size calculations and standard statistical tests were applied for comparative data analyses.

RESULTS

Of 592 children at the age of 12 months, 94% and 73% had received complete diphtheria-tetanus-pertussis component combination and pneumococcal conjugate vaccinations, respectively. At the age of 24 months, coverage rates for complete booster doses were 77% and 70%, respectively. Rates for MMR doses 1 and 2 at 24 months were 92% and 72%, respectively, and the rate for meningococcal conjugate vaccine (single dose) was 62%. On an average, coverage rates were similar in the 2 study regions except those for pneumococcal conjugate and second dose of MMR, which were approximately 10% higher in Geneva.

CONCLUSIONS

Compliance with supplementary vaccinations was lower than that with universally recommended vaccinations. This can be explained by the recent introduction of supplementary vaccinations or by the public perception that they are less important than universal vaccinations.