Results from the WHO external quality assessment for the respiratory syncytial virus pilot, 2016-17

Results from the second WHO external quality assessment for the molecular detection of respiratory syncytial virus, 2019-2020

Background

External quality assessments (EQAs) for the molecular detection of human respiratory syncytial virus (RSV) are necessary to ensure the standardisation of reliable results. The Phase II, 2019-2020 World Health Organization (WHO) RSV EQA included 28 laboratories in 26 countries. The EQA panel evaluated performance in the molecular detection and subtyping of RSV-A and RSV-B. This manuscript describes the preparation, distribution, and analysis of the 2019-2020 WHO RSV EQA.

Methods

Panel isolates underwent whole genome sequencing and in silico primer matching. The final panel included nine contemporary, one historical virus and two negative controls. The EQA panel was manufactured and distributed by the UK National External Quality Assessment Service (UK NEQAS). National laboratories used WHO reference assays developed by the United States Centers for Disease Control and Prevention, an RSV subtyping assay developed by the Victorian Infectious Diseases Reference Laboratory (Australia), or other in-house or commercial assays already in use at their laboratories.

Results

An in silico analysis of isolates showed a good match to assay primer/probes. The panel was distributed to 28 laboratories. Isolates were correctly identified in 98% of samples for detection and 99.6% for subtyping.

Conclusions

The WHO RSV EQA 2019-2020 showed that laboratories performed at high standards. Updating the composition of RSV molecular EQAs with contemporary strains to ensure representation of circulating strains, and ensuring primer matching with EQA panel viruses, is advantageous in assessing diagnostic competencies of laboratories. Ongoing EQAs are recommended because of continued evolution of mismatches between current circulating strains and existing primer sets.

RSV Prevention in All Infants: Which Is the Most Preferable Strategy?

Respiratory syncytial virus (RSV) causes a spectrum of respiratory illnesses in infants and young children that may lead to hospitalizations and a substantial number of outpatient visits, which result in a huge economic and healthcare burden. Most hospitalizations happen in otherwise healthy infants, highlighting the need to protect all infants against RSV. Moreover, there is evidence on the association between early-life RSV respiratory illness and recurrent wheezing/asthma-like symptoms As such, RSV is considered a global health priority. However, despite this, the only prevention strategy currently available is palivizumab, a monoclonal antibody (mAb) indicated in a subset of preterm infants or those with comorbidities, hence leaving the majority of the infant population unprotected against this virus. Therefore, development of prevention strategies against RSV for all infants entering their first RSV season constitutes a large unmet medical need. The aim of this review is to explore different immunization approaches to protect all infants against RSV. Prevention strategies include maternal immunization, immunization of infants with vaccines, immunization of infants with licensed mAbs (palivizumab), and immunization of infants with long-acting mAbs (e.g., nirsevimab, MK-1654). Of these, palivizumab use is restricted to a small population of infants and does not offer a solution for all-infant protection, whereas vaccine development in infants has encountered various challenges, including the immaturity of the infant immune system, highlighting that future pediatric vaccines will most likely be used in older infants (>6 months of age) and children. Consequently, maternal immunization and immunization of infants with long-acting mAbs represent the two feasible strategies for protection of all infants against RSV. Here, we present considerations regarding these two strategies covering key areas which include mechanism of action, "consistency" of protection, RSV variability, duration of protection, flexibility and optimal timing of immunization, benefit for the mother, programmatic implementation, and acceptance of each strategy by key stakeholders. We conclude that, based on current data, immunization of infants with long-acting mAbs might represent the most effective approach for protecting all infants entering their first RSV season.

A systematic review on global RSV genetic data: Identification of knowledge gaps

Respiratory syncytial virus (RSV) is a major health problem. A better understanding of the geographical and temporal dynamics of RSV circulation will assist in tracking resistance against therapeutics currently under development. Since 2015, the field of RSV molecular epidemiology has evolved rapidly with around 20–30 published articles per year. The objective of this systematic review is to identify knowledge gaps in recent RSV genetic literature to guide global molecular epidemiology research. We included 78 studies published between 2015 and 2020 describing 12,998 RSV sequences of which 8,233 (63%) have been uploaded to GenBank. Seventeen (22%) studies were performed in low‐ and middle‐income countries (LMICs), and seven (9%) studies sequenced whole‐genomes. Although most reported polymorphisms for monoclonal antibodies in clinical development (nirsevimab, MK‐1654) have not been tested for resistance in neutralisation essays, known resistance was detected at low levels for the nirsevimab and palivizumab binding site. High resistance was found for the suptavumab binding site. We present the first literature review of an enormous amount of RSV genetic data. The need for global monitoring of RSV molecular epidemiology becomes increasingly important in evaluating the effectiveness of monoclonal antibody candidates as they reach their final stages of clinical development. We have identified the following three knowledge gaps: whole‐genome data to study global RSV evolution, data from LMICs and data from global surveillance programs.

Rapid detection of human respiratory syncytial virus A and B by duplex real-time RT-PCR

Respiratory syncytial virus (RSV) is a common cause of acute respiratory disease worldwide, especially in young children. The World Health Organization (WHO) has initiated an RSV Surveillance Pilot program that aims to perform worldwide RSV surveillance, requiring the development of reliable and rapid molecular methods to detect and identify RSV. A duplex real-time RT-PCR assay developed for simultaneous detection of both A and B subtypes of RSV was included as part of this program. This duplex assay targeted a conserved region of the RSV polymerase gene and was validated for analytical sensitivity, specificity, reproducibility and clinical performance with a wide range of respiratory specimens. The assay was highly specific for RSV and did not react with non-RSV respiratory pathogens, including the SARS-CoV-2 virus.

Circulation of human coronaviruses OC43 and 229E in Córdoba, Argentina

This is the first study of respiratory infections in Córdoba, Argentina, caused by endemic human coronavirus (HCoV)-OC43 and HCOV-229E, which circulated during 2011-2012 at a 3% rate, either as single or multiple infections. They were detected mainly in children, but HCoV-229E was also found in adults. HCoV-229E was detected in five out of 631 samples (0.8%), and HCoV-OC43 was found in 14 out of 631 (2.2%) samples. Clinical manifestations ranged from fever to respiratory distress, and a significant association of HCoV-229E with asthma was observed. Further studies and surveillance are needed to provide better clinical insights, early diagnosis, and medical care of patients, as well as to contribute to epidemiology modeling and prevention.

Results from the WHO external quality assessment for the respiratory syncytial virus pilot, 2016-17

Background

External quality assessments (EQAs) for the molecular detection of respiratory syncytial virus (RSV) are necessary to ensure the provision of reliable and accurate results. One of the objectives of the pilot of the World Health Organization (WHO) Global RSV Surveillance, 2016‐2017, was to evaluate and standardize RSV molecular tests used by participating countries. This paper describes the first WHO RSV EQA for the molecular detection of RSV.

Methods

The WHO implemented the pilot of Global RSV Surveillance based on the WHO Global Influenza Surveillance and Response System (GISRS) from 2016 to 2018 in 14 countries. To ensure standardization of tests, 13 participating laboratories were required to complete a 12 panel RSV EQA prepared and distributed by the Centers for Disease Control and Prevention (CDC), USA. The 14th laboratory joined the pilot late and participated in a separate EQA. Laboratories evaluated a RSV rRT‐PCR assay developed by CDC and compared where applicable, other Laboratory Developed Tests (LDTs) or commercial assays already in use at their laboratories.

Results

Laboratories performed well using the CDC RSV rRT‐PCR in comparison with LDTs and commercial assays. Using the CDC assay, 11 of 13 laboratories reported correct results. Two laboratories each reported one false‐positive finding. Of the laboratories using LDTs or commercial assays, results as assessed by Ct values were 100% correct for 1/5 (20%). With corrective actions, all laboratories achieved satisfactory outputs.

Conclusions

These findings indicate that reliable results can be expected from this pilot. Continued participation in EQAs for the molecular detection of RSV is recommended.