We checked the vaccine records and measles antibody titers of all medical and clerical staff at our hospital in accordance with the measles response guidelines at medical facilities to determine the need for revaccination since 2016. Based on the results in 2017, 397 employees were judged to be in need of revaccination, and of these, 319 were revaccinated in the period from then to the present. As a result, the guideline compliance rate has risen from 48% to 89%. However, analysis of antibody titers revealed that the number of employees who had higher antibody titers than the guideline's standard level was low, especially in younger generations. Among employees over 40 years old, most of whom had not received the measles vaccine, more than 70% had higher antibody levels than the standard. But among employees who were 28-39 years old, most of whom had received the vaccine once, only 48% were higher than the standard level; among employees between 21 and 27 years old, most of whom had received the vaccine twice, only 35% were higher than the standard level. Moreover, a very low antibody titer, which was under 3.0, was observed in one young employee who had received the vaccine twice, indicating a high chance of contracting measles. Considering the results, we think that it is more important to factor in antibody levels when planning the deployment of staff during measles outbreaks.
Our hospital is a regional core hospital with 475 beds, and the 25-year-old building is a steel reinforced concrete structure with 1 floor underground and 10 floors above ground. A 79-year-old woman who had been treated with prednisolone 45 mg/day for Evans syndrome had a high fever on day 9 after prednisolone administration. She was diagnosed with Legionella pneumonia based on a lung consolidation on her chest X-ray with a positive urinary antigen for Legionella. Upon investigation of the water supply and hot water supply system on the suspicion of nosocomial Legionella infection, Legionella pneumophila serogroup 1 was detected in the hot water supply systems of all the wards on the 5th-10th floors. We then genotyped the Legionella from the patient and confirmed that the strain was the same as the L. pneumophila detected from the water supply system. To eliminate the nosocomial Legionella infections, we conducted hot water flushing and shower hose disinfection and replacement of all hot water taps and revised ward care restrictions. Then, we performed Legionella culture at 82 randomly selected locations after flushing and confirmed the absence of L. pneumophila, except one location where it was continuously detected due to the branched pipes that were not recognized and the flushing was not enough. We finally confirmed the absence of L. pneumophila after the flushing was carried throughout the pipes with the stagnated water. We also conducted follow-up surveys of patients who were discharged or transferred to other hospitals and health surveys for hospital staff. There was no new patient other than our patient; however, during the inspection to regularly monitor the Legionella contamination in the water supply system, L. pneumophila was detected again in a hot water tap that was used less frequently, which could be due to a contamination from biofilm. Our experience suggests that once L. pneumophila is detected from the water supply system, it is necessary to manage a long-term plan to eliminate the contamination that could persist due to biofilm formation in the pipes. Based on the experience, we established a manual for our hospital.