Phylogenetic analysis of rubella virus strains from an outbreak in Madrid, Spain, from 2004 to 2005

Migration and outbreaks of vaccine-preventable disease in Europe: a systematic review

Migrant populations are one of several underimmunised groups in the EU or European Economic Area (EU/EEA), yet little is known about their involvement in outbreaks of vaccine-preventable diseases. This information is vital to develop targeted strategies to improve the health of diverse migrant communities. We did a systematic review (PROSPERO CRD42019157473; Jan 1, 2000, to May 22, 2020) adhering to PRISMA guidelines, to identify studies on vaccine-preventable disease outbreaks (measles, mumps, rubella, diphtheria, pertussis, polio, hepatitis A, varicella, Neisseria meningitidis, and Haemophilus influenzae) involving migrants residing in the EU/EEA and Switzerland. We identified 45 studies, reporting on 47 distinct vaccine-preventable disease outbreaks across 13 countries. Most reported outbreaks involving migrants were of measles (n=24; 6496 cases), followed by varicella (n=11; 505 cases), hepatitis A (n=7; 1356 cases), rubella (n=3; 487 cases), and mumps (n=2; 293 cases). 19 (40%) outbreaks, predominantly varicella and measles, were reported in temporary refugee camps or shelters. Of 11 varicella outbreaks, nine (82%) were associated with adult migrants. Half of measles outbreaks (n=11) were associated with migrants from eastern European countries. In conclusion, migrants are involved in vaccine-preventable disease outbreaks in Europe, with adult and child refugees residing in shelters or temporary camps at particular risk, alongside specific nationality groups. Vulnerability varies by disease, setting, and demographics, highlighting the importance of tailoring catch-up vaccination interventions to specific groups in order to meet regional and global vaccination targets as recommended by the new Immunisation Agenda 2030 framework for action. A better understanding of vaccine access and intent in migrant groups and a greater focus on co-designing interventions is urgently needed, with direct implications for COVID-19 vaccine delivery.

Genetic Characterization of Rubella Virus Strains Detected in Spain, 1998-2014

The National Plan for the Elimination of Rubella was implemented in Spain in 2008 using the logistics of the National Plan for the Elimination of Measles that have been employed since year 2000. Molecular characterization of rubella virus (RUBV) is important for disease surveillance and for monitoring elimination of the disease throughout the world. We describe the first complete series of data regarding the circulation of RUBV genotypes in Spain. The 739-nucleotide fragment designated by the WHO for RUBV genotyping was sequenced in 88 selected cases collected from 1998 to 2014. Five genotypes were identified: 1E, 2B, 1J, 1I, and 1a. Genotype 1E was predominant between 1998 and 2003 but was replaced by genotype 2B, which was detected in sporadic cases in 2004, 2006, 2008, 2012, 2013 and 2014. There was an outbreak of genotype 2B in Algeciras (Andalusia) in 2008. Genotype 1J caused an outbreak in Madrid in 2004/2005 and sporadic cases in 2005 and 2007. Genotype 1I was found to have infected an immune-suppressed patient with neurological symptoms in 2008. Finally, vaccine strain RA 27/3 was detected in three sporadic cases, two of them immune-suppressed and without a recent history of vaccination. This suggests that during these years there were a series of imported sporadic cases and outbreaks, confirming the findings of epidemiological data analysis. The importation sources were generally consistent with our geographic and cultural ties, mainly with Europe (genotypes 1E, 2B, 1I) and Latin America (1J).

Molecular evolutionary and epidemiological dynamics of genotypes 1G and 2B of rubella virus

Rubella Virus (RV), which causes measles-like rashes in children, puts millions of infants at risk of congenital defects across the globe. Employing phylogenetic approaches to the whole genome sequence data and E1 glycoprotein sequence data, the present study reports the substitution rates and dates of emergence of all thirteen previously described rubella genotypes, and gains important insights into the epidemiological dynamics of two geographically widely distributed genotypes 1G and 2B. The overall nucleotide substitution rate of this non-vector-borne RV is in the order of 10-3 substitutions/site/year, which is considerably higher than the substitution rates previously reported for the vector-borne alphaviruses within the same family. Currently circulating strains of RV share a common ancestor that existed within the last 150 years, with 95% Highest Posterior Density values ranging from 1868 to 1926 AD. Viral strains within the respective genotypes began diverging between the year 1930 s and 1980 s. Both genotype 1G and 2B have shown a decline in effective number of infections since 1990 s, a period during which mass immunization programs against RV were adapted across the globe. Although both genotypes showed some extent of spatial genetic structuring, the analyses also depicted an inter-continental viral dispersal. Such a viral dispersal pattern could be related to the migration of infected individuals across the regions coupled with a low coverage of MMR vaccination.

Genotyping of rubella virus RNA in sera and dried blood spots collected during routine surveillance and in archival sera

Information on the molecular epidemiology of rubella has been valuable in supporting efforts to control and eliminate rubella in several countries. The preferred samples for virus isolation or RNA detection, such as throat swabs, are often not available making it difficult to obtain a robust database of rubella virus sequences. A method for obtaining rubella virus genotypes from more commonly collected samples such as sera or dried blood spots using real-time RT-PCR to screen samples followed by nested set amplification is described. Rubella genotypes were obtained from dried blood spots and recent and archival sera collections. Eighteen percent of the RNAs extracted from the archival sera were real-time RT-PCR positive, and 44% of these RNAs were amplified successfully by nested RT-PCR and sequenced. Implementation of this technique could provide another tool to improve global rubella molecular surveillance.

Phylogenetic analysis of rubella viruses in Vietnam during 2009-2010

Rubella virus (RV) usually causes a mild disease. However, infection during the first trimester of pregnancy often leads to severe birth defects known as congenital rubella syndrome (CRS). Although wild-type RVs exist and circulate worldwide, their genotypes remain unknown in many countries. The aim of this study was to identify the molecular characteristics of RVs found in Vietnam during the years 2009-2010 and to provide the first data concerning RV genotypes in this country. Throat swab samples were collected between 2009 and 2010 from four CRS cases and nine rubella infection cases visiting one Children's Hospital and one outpatient clinic in Ho Chi Minh City. The 739-nucleotide coding region of the RV E1 gene recommended by the World Health Organization was amplified by reverse transcriptase PCR, and the resulting DNA fragments were then sequenced. Sequences were assigned to genotypes by phylogenetic analysis with RV reference strains. RV RNA was detected in 11 clinical specimens. Phylogenetic analysis of the sequences showed that all 11 strains belonged to 2B genotype. Several variations in amino acids were found, among which five changes were involved in the B and T cell epitopes. These data indicate that viruses of genotype 2B were circulating in Vietnam. The increasing information about RV genotype in Vietnam should aid in the control of rubella infection and CRS in this country.