Assessing the Reliability of SARS-CoV-2 Neutralization Studies That Use Post-Vaccination Sera

Assessing COVID-19 vaccine effectiveness against emerging SARS-CoV-2 variants is crucial for determining future vaccination strategies and other public health strategies. When clinical effectiveness data are unavailable, a common method of assessing vaccine performance is to utilize neutralization assays using post-vaccination sera. Neutralization studies are typically performed across a wide array of settings, populations and vaccination strategies, and using different methodologies. For any comparison and meta-analysis to be meaningful, the design and methodology of the studies used must at minimum address aspects that confer a certain degree of reliability and comparability. We identified and characterized three important categories in which studies differ (cohort details, assay details and data reporting details) and that can affect the overall reliability and/or usefulness of neutralization assay results. We define reliability as a measure of methodological accuracy, proper study setting concerning subjects, samples and viruses, and reporting quality. Each category comprises a set of several relevant key parameters. To each parameter, we assigned a possible impact (ranging from low to high) on overall study reliability depending on its potential to influence the results. We then developed a reliability assessment tool that assesses the aggregate reliability of a study across all parameters. The reliability assessment tool provides explicit selection criteria for inclusion of comparable studies in meta-analyses of neutralization activity of SARS-CoV-2 variants in post-vaccination sera and can also both guide the design of future neutralization studies and serve as a checklist for including important details on key parameters in publications

Prevalence of Livestock-Associated MRSA in Communities with High Pig-Densities in The Netherlands

Contains fulltext : 124345.pdf (publisher's version ) (Open Access)BACKGROUND: Recently, livestock-associated methicillin-resistant Staphylococcus aureus CC398 has been discovered in animals, livestock farmers and retail meat. This cross-sectional study aimed to determine the spread to persons not in direct contact with livestock in areas with a high density of pig farms. METHODOLOGY/PRINCIPAL FINDINGS: With a random mailing in 3 selected municipalities in The Netherlands, adult persons were asked to fill in a questionnaire and to take a nose swab. In total, complete information was obtained on 583 persons. Of the 534 persons without livestock-contact, one was positive for MRSA (0.2%; 95% confidence interval, <0.01-1.2). Of the 49 persons who did indicate to be working at or living on a livestock farm, 13 were positive for MRSA (26.5%; 95% confidence interval, 16.1-40.4). All spa-types belonged to CC398. CONCLUSIONS/SIGNIFICANCE: Livestock-associated MRSA has a high prevalence in people with direct contact with animals. At this moment it has not spread from the farms into the community

Appearance of a novel measles G3 strain in multiple European countries within a two month period, 2010

During late 2010, a previously unrecognised strain of measles genotype G3 virus was identified in five different European countries by the World Health Organization Measles and Rubella Laboratory Network. Apart from one, none had a travel history to south-east Asia, the usual source of G3 viruses, although epidemiological links could be established between some of the cases. This case series illustrates the value of genotyping and sequencing in tracking measles infections, and identifying otherwise unrecognised chains of transmission

Measles Virus Genotyping by Nucleotide-Specific Multiplex PCR

A simple genotyping method based on multiplex PCR has been developed to discriminate between all active measles virus (MV) clades and genotypes (A, B3.1, B3.2, C2, D2-D9, G2-G3, and H1-H2). The sequencing reaction was replaced by six multiplex PCRs: one to identify the clade and five to identify the respective genotype. Primers were sensitive to clade- and genotype-specific nucleotides and generated fragments of type-specific sizes that were analyzed by conventional agarose gel electrophoresis. On the basis of all published MV sequences, positive and negative predictive values of 99.2% and 98.6% were calculated. Variability in the primer binding sites, which could potentially reduce sensitivity, was very limited among published sequences. As new genotypes are described, additional specific primers can be included in the multiplex PCR with relative ease. Although sequencing remains the “gold standard,” the present method should facilitate MV genotyping especially in developing countries and will therefore contribute to enhanced MV control and elimination strategies as recommended by the World Health Organization

Molecular genotyping and epidemiology of measles virus transmission in the World Health Organization European Region, 2007-2009

Background: In 2002, the World Health Organization (WHO) adopted a goal to eliminate measles in the European Region by 2010. Measles elimination is defined as the interruption of indigenous measles virus (MV) transmission. The molecular epidemiology of MV transmission in the WHO European Region was studied through the investigation of reported cases and outbreaks to monitor the region's progress toward its measles elimination goal. Methods: National and regional laboratories performed molecular characterization of MV detected between 2007 and 2009 in the WHO European Region. To document indigenous transmission and importations into the region, we analyzed genotyping results and epidemiological data on measles outbreaks reported by the member states. Results: Since 2007, MV genotype D6 has not been reported in the WHO European Region, suggesting that its chains of transmission have been interrupted, whereas several other MV genotypes are still circulating. Although several European countries have already interrupted indigenous MV transmission, genotyping showed that 3 endemic MV transmission chains have been reestablished in other countries. Conclusions: The WHO European Region 2010 goal will not be met, as indigenous transmission of MV has not been interrupted. As the region begins to document its process of elimination verification to monitor progress toward the goal, countries will need to ensure that genotyping is performed in all measles outbreaks

Real-Time PCR for Measles Virus Detection on Clinical Specimens with Negative IgM Result in Morocco.

Since the confirmation of measles cases represents an important indicator regarding the performance of the measles-elimination program, the aim of this study was to evaluate the effectiveness of the routine procedures followed in Morocco for the laboratory confirmation of measles cases. Suspected cases reported between January 2010 and December 2012 were assessed for the timeliness of the sample collection, occurrence of measles clinical symptoms, and the results of the laboratory diagnoses. For 88% of the 2,708 suspected cases, a clinical specimen was collected within 7d of rash onset, of which 50% were IgM-positive and 2.6% were equivocal. The measles symptoms were reported in 91.4% of the cases; the occurrence of symptoms showed a positive association with the serological results (odds ratio [OR] = 2.9883, 95% confidence interval [CI] 2.2238-4.0157). Of the negative samples, 52% (n = 116) tested positive by real-time polymerase chain reaction (PCR). These results are in favor of using molecular detection to complement serological diagnosis in the context of measles surveillance approach in Morocco. In addition, the introduction of additional laboratory methods for differential diagnosis is required for the final classification of suspected cases with maculopapular rash and fever in the context of the measles elimination program