A Multi-Laboratory Evaluation of Commercial Monkeypox Virus Molecular Tests

In this report, we describe the first national scale multi-laboratory evaluation of monkeypox virus (MPXV) DNA commercial PCR kits. The objective of this study was to evaluate 2 kits by different diagnostic laboratories across Israel. Ten standardized samples were tested simultaneously using the Novaplex (15 laboratories) and Bio-Speedy (seven laboratories) kits. An in-house assay based on previously published reactions was used as reference. Comparison of the results showed high intra-assay agreement between laboratories, with small variations for most samples. The in-house assay had an analytical detection limit of less than 10 copies per reaction. While the 2 commercial kits were able to detect specimens with low viral loads similarly to the in-house assay, significant differences were observed, in the Cq values and relative fluorescence (RF), between the assays. The RF signal of the in-house and Bio-Speedy assays ranged between 5,000 and 10,000 RFU, while the signal in the Novaplex assay was less than 600 RFU. Due to the kit measurement protocol, the Cq values of the Bio-Speedy kit were 5 to 7.5 cycles lower than those of the in-house assay. On the contrary, the Cq values of the Novaplex kit were significantly higher than those of the in-house assay, with differences of 3 to 5 cycles per sample. Our results suggest that while all assays were similar in their overall sensitivity, direct comparison of Cq values between them may be misleading. To our knowledge, this is the first methodical evaluation of commercial MPX test kits. We therefore anticipate that this study would help diagnostic laboratories in choosing a specific MPX detection assay. IMPORTANCE To the best of our knowledge, this study is the first methodical evaluation of commercial kits designed for Monkeypox virus detection. This was done by performing the same tests using the same sample set in multiple laboratories, simultaneously, on a national scale. It therefore provides important and unique information on the performance of such kits and provides a guideline for choosing the assay of choice for monkeypox virus diagnosis in a standard diagnostic laboratory. It also demonstrates potential complications when trying to compare the results of different assays, even when testing exactly the same samples, under identical conditions.

Humoral response and breakthrough infections with SARS-CoV-2 B.1.617.2 variant in vaccinated maintenance hemodialysis patients

INTRODUCTION

Breakthrough COVID-19 may occur in vaccinated people, and may result from declining vaccine effectiveness or highly transmittable SARS-CoV-2 variants, such as the B.167.2 (delta) variant. We investigated risk factors and outcomes for infection with the delta variant among vaccinated hemodialysis patients.

METHODS

Patients on maintenance hemodialysis who received two doses of the BNT162b2 (Pfizer-BioNTech) vaccine were analysed according to having developed COVID-19 (study group) or not (control group), in a retrospective, observational, comparative study. We compared risk-factors for developing breakthrough COVID-19 and assessed clinical outcomes, including 30-day mortality rates.

RESULTS

Twenty-four cases of breakthrough SARS-CoV-2 infection were compared to 91 controls without infection. Breakthrough infection was associated with chronic immunosuppressive treatment, hematological malignancies, and low antibody levels against SARS-CoV-2 spike protein. All COVID-19 cases occurred at least 5 months after vaccination, and most were caused by the B.1.617.2 variant (at least 23/24 cases). COVID-19 was categorized as severe or critical disease in 11/24 patients (46%), and 54% required hospitalization and COVID-19-directed treatment. The source of infection was nosocomial in 6/24 cases (25%), and healthcare-related in 3/24 (12.5%). Mortality rate was 21%. Overall mortality was significantly higher in patients who developed COVID-19 than in controls (odds ratio for all-cause mortality 7.6, 95% CI 1.4-41, p = 0.002).

CONCLUSIONS

Breakthrough COVID-19 with the B.1.617.2 variant can occur in vaccinated hemodialysis patients and is associated with immunosuppression and weaker humoral response to vaccination. Infections may be nosocomial and result in significant morbidity and mortality.

Antiphospholipid antibodies during infectious mononucleosis and their long term clinical significance

BACKGROUND

The prevalence of antiphospholipid antibodies (aPLs) during acute Epstein-Barr virus (EBV) infection may be as high as 30-60%. The role of these autoantibodies in the development of antiphospholipid syndrome (APS) is not clear.

OBJECTIVE

To investigate the prevalence, persistence and clinical significance of aPLs in a series of patients diagnosed with acute EBV infection.

STUDY DESIGN

A cohort of 94 patients aged 15 or older, recently diagnosed with acute EBV was retrieved. Serum samples obtained during diagnosis were tested for the presence of aPLs and anti-β2GP antibodies. Patients with positive sera for aPLs were assessed for the persistence of aPLs and the development of APS.

RESULTS

The prevalence of aPLs among 94 patients with acute EBV was 37.2%. Five of 27 available serum samples were also positive for anti-β2 glycoprotein (anti-β2GP) antibodies. Repeat testing for aPLs after a median of 21 months post acute infection (range 13-50 months) was performed in 17 of the 35 patients with positive aPL test. All 17 patients were found negative for aPL-IgG antibodies. Two of them had positive aPL-IgM antibodies and positive anti-β2GP antibodies. None of the patients who had positive aPLs experienced any manifestations of APS.

CONCLUSION

The disappearance of aPLs in the majority of the patients after acute EBV infection, along with the absence of consistent clinical findings, suggests that the detection of aPLs during acute EBV is not associated with the development APS over time.

High seroprevalence of human metapneumovirus among young children in Israel

Exposure to the newly discovered human metapneumovirus (HMPV) during the first 2 years of life was studied by longitudinal serological analysis in 40 healthy children in southern Israel. The seropositivity rate decreased to a minimum by age 13 months and increased to 52% by age 24 months. Evidence of new infection was detected in 13%, 23%, and 55% of children by ages 7, 13, and 24 months, respectively. The high exposure rates suggest that HMPV may be an important cause of community-acquired respiratory-tract infections in young children.