Use of a multiplex polymerase chain reaction assay for the early detection of an outbreak of human parainfluenza virus type 3 infection in a nursery school during the COVID-19 pandemic.

Introduction: Although outbreaks of parainfluenza virus type 3 (PIV-3) have been reported in children, to our knowledge none have been reported in a nursery school. As the symptoms of PIV-3 infection are similar to those of COVID-19 infection, accurate diagnosis of PIV-3 and other respiratory viruses is important during the COVID-19 pandemic. Aims: We experienced an outbreak of upper respiratory symptoms at a nursery school in Miyagi Prefecture, Japan, from 29/5/2021 to 13/6/2021 and aimed to determine the causative organism(s). Methods: A multiplex polymerase chain reaction (PCR) assay which enabled rapid detection of a variety of causative microorganisms of respiratory tract infections was used to analyse 13 nasopharyngeal swabs collected during the outbreak. Infection Prevention and control measures were implemented to prevent further spread of infection. Results: All 13 samples were positive for PIV-3 infection. 2 of the 13 samples were also positive for rhinovirus/enterovirus and 1 sample was also positive rhinovirus/enterovirus and coronavirus NL 63. No samples were positive for SARS-CoV-2. Discussion: Children in school settings are especially vulnerable to respiratory viral infections, including COVID-19. Children under two years are unable to wear masks reliably, and the COVID-19 vaccine was approved only for older children. Multiplex PCR assays can be used for the rapid diagnosis of respiratory infections. Conclusion: We identified an outbreak of PIV-3 in a nursery school during the COVID-19 pandemic. The investigation of the outbreak highlighted that it was important not to overlook other respiratory infections including PIV-3 during the COVID-19 pandemic. The multiplex PCR assay provided rapid and accurate diagnosis of the causative organisms in the outbreak and helped to direct appropriate interventions to control the outbreak.

[BASELINE SCREENING USING INTERFERON-GAMMA RELEASE ASSAY SUGGESTS AN INCREASED RISK OF MYCOBACTERIUM TUBERCULOSIS INFECTION AMONG EMPLOYEES IN A JAPANESE GENERAL HOSPITAL].

OBJECTIVES: This retrospective study aimed to assess the risk of tuberculosis infection for the employees of a Japanese hospital using baseline interferon-gamma release assay (IGRA). The risk was defined as exposure to the hospital environment. METHODS: In total, 870 hospital employees including 161 new employees, 582 for baseline assay, and 127 for contact examination (709 subjects in the post-employment group) were examined from December 2010 to April 2012. The new employees were considered as the "non-exposure" group, whereas the post-employment group was considered as the "exposure" group. Multiple logistic regression analyses were used to calculate the odds ratio (OR) for IGRA positivity, adjusted for gender, smoking history, and alcohol intake (model 1), and for years of employment (model 2). RESULTS: The exposure group was significantly associated with an increased risk of positive IGRA results, even when adjusted for years of employment (OR: 4.1; 95% confidence interval: 1.4-17.6; P = 0.007). Subgroup analyses stratified by profession indicated a significantly increased OR for laboratory technicians, doctors, and nurses in both models. No correlation was observed between the length of employment and IGRA positivity. CONCLUSION: Exposure to the hospital environment increased the risk of tuberculosis infection for employees irrespective of the length of employment. Laboratory technicians, doctors, and nurses were at the highest risk of infection.