Shedding of Rubella Virus among Infants with Congenital Rubella Syndrome Born in Tokyo, Japan, 2013-2014

Rubella virus tropism and single-cell responses in human primary tissue and microglia-containing organoids

Rubella virus is an important human pathogen that can cause neurological deficits in a developing fetus when contracted during pregnancy. Despite successful vaccination programs in the Americas and many developed countries, rubella remains endemic in many regions worldwide and outbreaks occur wherever population immunity is insufficient. Intense interest since rubella virus was first isolated in 1962 has advanced our understanding of clinical outcomes after infection disrupts key processes of fetal neurodevelopment. Yet it is still largely unknown which cell types in the developing brain are targeted. We show that in human brain slices, rubella virus predominantly infects microglia. This infection occurs in a heterogeneous population but not in a highly microglia-enriched monoculture in the absence of other cell types. By using an organoid-microglia model, we further demonstrate that rubella virus infection leads to a profound interferon response in non-microglial cells, including neurons and neural progenitor cells, and this response is attenuated by the presence of microglia.

10-Year survey on serum antibody positivity rates and titers for measles and rubella in healthcare workers; an observational study at a Japanese university hospital

BACKGROUND

We evaluated the effect of the two-dose vaccination strategy, which has been a widely adopted as childhood routine schedule worldwide to acquire herd immunity, on healthcare workers (HCWs) in Japan.

METHODS

Between 2010 and 2019, antibody titers for measles and rubella were measured annually among newly employed HCWs at Osaka University Hospital, Japan, using Enzygnost® assays (Siemens Healthcare Diagnostics Co. Ltd., Marburg, Germany). The data were categorized by age to compare the antibody positivity rates and antibody titers among no-vaccine, single-dose, and two-dose groups.

RESULTS

Over the 10-year period, the annual antibody positivity rates for measles and rubella were 84.0%-95.3% and 90.0%-94.5%, respectively, without any particular trend. The antibody titers for measles (median [interquartile range]: 8.4 [3.9, 20] vs. 6.1 [3.5, 12]) and rubella (11 [5.5, 20] vs. 6 [3.7, 11]) were statistically lower (p < 0.001) in the two-dose generation than in the single-dose generation.

DISCUSSION

A shift from single-dose to two-dose vaccination did not yield an increase in antibody positivity rates for both measles and rubella among HCWs. Notably, antibody titers were significantly lower in the two-dose generation.

CONCLUSION

Despite several limitations, our data suggests a paradoxical vulnerability in young HCWs who received the two-dose vaccination in a view of sero-positivity rates.

Mechanism of heparin interference in detection of LIAISON® Rubella IgM

AIMS

To investigate the effects of heparin in detection of LIAISON® Rubella IgM (Rub-M) and the mechanism of interference.

METHODS

Different concentrations of lithium heparin and sodium heparin were added to ten serum samples. The relative light units (RLU) value of Rub-M was measured using the LIAISON XL detection system. Different levels of IgM serum were incubated with magnetic particle in Rub-M detection kit at 4 °C for 4 h, blocking anti-human IgM-specific antibodies coated on the surface of magnetic particle. Separately, the rubella virus antigen in Rub-M detection kit was replaced by phosphate-buffered saline (PBS). The RLU values of LIAISON® Rub-M of original serum and serum containing various concentrations of heparin were measured after the above two different treatments.

RESULTS

The RLU value of LIAISON® Rub-M increased with the increase of heparin content lower than 40 IU/mL, and reached a peak value at 40-50 IU/mL. The RLU value of LIAISON® Rub-M then decreased with the decrease of heparin concentration. When rubella virus antigen was replaced by PBS, the RLU value of LIAISON® Rub-M of serum samples containing 40 IU/mL heparin decreased significantly. The blocking concentration of IgM increased gradually, and the RLU value of LIAISON® Rub-M of seven serum samples containing 40 IU/mL heparin also decreased gradually.

CONCLUSION

Plasma with heparin cannot be used to the detection of LIAISON® Rub-M. Heparin may participate in the reaction by binding with rubella virus antigen and anti-human IgM-specific antibodies coated on the surface of magnetic particle, thus affecting the detection results.

Performance of Zika Assays in the Context of Toxoplasma gondii, Parvovirus B19, Rubella Virus, and Cytomegalovirus (TORCH) Diagnostic Assays

Infections during pregnancy that may cause congenital abnormalities have been recognized for decades, but their diagnosis is challenging. This was again illustrated with the emergence of Zika virus (ZIKV), highlighting the inherent difficulties in estimating the extent of pre- and postnatal ZIKV complications because of the difficulties in establishing definitive diagnoses. We reviewed the epidemiology, infection kinetics, and diagnostic methods used for Toxoplasma gondii, parvovirus B19, rubella virus, and cytomegalovirus (TORCH) infections and compared the results with current knowledge of ZIKV diagnostic assays to provide a basis for the inclusion of ZIKV in the TORCH complex evaluations. Similarities between TORCH pathogens and ZIKV support inclusion of ZIKV as an emerging TORCH infection. Our review evaluates the diagnostic performance of various TORCH diagnostic assays for maternal screening, fetal screening, and neonatal screening. We show that the sensitivity, specificity, and positive and negative predictive value of TORCH complex pathogens are widely variable, stressing the importance of confirmatory testing and the need for novel techniques for earlier and accurate diagnosis of maternal and congenital infections. In this context it is also important to acknowledge different needs and access to care for different geographic and resource settings.

Simultaneous and rapid detection method for measles and rubella using single-tube multiplex real-time quantitative RT-PCR

Patients with measles or rubella infections manifest acute onset fever accompanying systemic exanthema, which are clinically difficult to be distinguish. Rapid diagnosis and differentiation of such epidemic viral diseases is essential to prevent outbreaks. We developed a single-tube multiplex real-time PCR assay for these indistinguishable viruses. We used previously-reported primer settings, with a slight modification of reporter dye, and applied to multiplex Taqman real-time PCR by cobas z480 (Roche Molecular Systems, Inc.). Consequently, the assay could detect 10 copies/10 μl of measles and rubella with coefficient of variations of 11.2% and 21.8%, respectively. Strengths of our methodology include simplicity of operation, short measurement time (2 h), uses of internal control (confirming a run of PCR), and quantitative measurement with high sensitivity. Both measles and rubella currently cause social outbreaks in Japan. We hope that our single-tube multiplex assay contributes to an early diagnosis, leading to an appropriate infection control measure and prevention of epidemics.

Anti-Jo-1 Antibody-positive Interstitial Pneumonia in an Elderly Patient with Congenital Rubella Syndrome

A 71-year-old woman with congenital rubella syndrome (CRS) presented with prolonged cough. No physical findings suggested the presence of any connective tissue diseases. Chest computed tomography showed ground-glass opacities and consolidations in the bilateral lower lobes. She had elevated serum Krebs von den Lungen-6, hypoxemia and positive serum anti-Jo-1 antibody. Bronchoalveolar lavage fluid revealed lymphocytosis with a decreased CD4/CD8 ratio. A transbronchial lung biopsy specimen revealed organizing pneumonia. Based on a diagnosis of interstitial pneumonia with autoimmune features (IPAF), systemic corticosteroids were administered, and a good outcome was obtained. A possible relationship between CRS and IPAF is herein discussed.

Prevention of Infectious Diseases due to Immunosuppression and Vaccinations in Asian Patients with Inflammatory Bowel Disease

Background

Inflammatory bowel disease (IBD) patients with immunocompromise have a high risk of developing complications related to viral infections. Western countries were the first to formulate vaccine guideline. Asian countries developed their national and international vaccine guidelines a little later in order to reduce the risk of mortality from viral infections. However, no studies to date have examined the differences in vaccinations that prevail among Asian countries.

Summary

This review summarizes the vaccination status and schedules in various Asian countries for immunocompromised IBD patients. Vaccination rates, regardless of the specific vaccine, were high in Japan, South Korea, and China and low in India and the Philippines. Vaccine schedules differed by country, and outbreaks of measles and rubella were seen due to low vaccination rates in Southeast Asia and South Asia. Live vaccines cannot be administered during immunosuppressive treatment. Infection with measles, mumps, and varicella during immunosuppressive therapy carries a high risk of mortality, and thus confirmation of immunization status is recommended as soon as IBD is diagnosed and, when possible, live vaccines should be administered before the initiation of immunosuppressive treatment. In patients seronegative for hepatitis B, administration of the hepatitis B vaccine is also recommended.

Key Messages

Physicians, while considering severity of outbreaks, should understand the differences in vaccination status that exist among the various Asian countries and regions.