Vincent C C Cheng1,2, Shuk-Ching Wong2, Sally C Y Wong1, Siddharth Sridhar3, Jonathan H K Chen1, Cyril C Y Yip1, Derek L L Hung1, Xin Li1, Vivien W M Chuang4, Owen T Y Tsang5, Gibson K S Woo6, Shuk-Kwan Chuang7, Kwok-Yung Yuen3. 1. Department of Microbiology, Queen Mary Hospital, Hong Kong Special Administrative Region, China. 2. Infection Control Team, Queen Mary Hospital, Hong Kong West Cluster, Hong Kong Special Administrative Region, China. 3. Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China. 4. Quality & Safety Division (Infection, Emergency, and Contingency), Hospital Authority, Hong Kong Special Administrative Region, China. 5. Infectious Disease Center, Hospital Authority, Hong Kong Special Administrative Region, China. 6. Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, China. 7. Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, China.
Abstract
OBJECTIVE: To report an outbreak of measles with epidemiological link between Hong Kong International Airport (HKIA) and a hospital. METHODS: Epidemiological investigations, patients' measles serology, and phylogenetic analysis of the hemagglutinin (H) and nucleoprotein (N) genes of measles virus isolates were conducted. RESULTS: In total, 29 HKIA staff of diverse ranks and working locations were infected with measles within 1 month. Significantly fewer affected staff had history of travel than non-HKIA-related measles patients [10 of 29 (34.5%) vs 28 of 35 (80%); P < .01]. Of 9 airport staff who could recall detailed exposure history, 6 (66.7%) had visited self-service food premises at HKIA during the incubation period, where food trays, as observed during the epidemiological field investigation, were not washed after use. Furthermore, 1 airport baggage handler who was admitted to hospital A before rash onset infected 2 healthcare workers (HCWs) known to have 2 doses of MMR vaccination with positive measles IgG and lower viral loads in respiratory specimens. Infections in these 2 HCWs warranted contact tracing of another 168 persons (97 patients and 71 HCWs). Phylogenetic comparison of H and N gene sequences confirmed the clonality of outbreak strains. CONCLUSION: Despite good herd immunity with overall seroprevalence of >95% against measles, major outbreaks of measles occurred among HKIA staff having daily contact with many international pssengers. Lessons from severe acute respiratory syndrome (SARS) and measles outbreaks suggested that an airport can be a strategic epidemic center. Pre-exanthem transmission of measles from airport staff to HCWs with secondary vaccine failure poses a grave challenge to hospital infection control.
OBJECTIVE: To report an outbreak of measles with epidemiological link between Hong Kong International Airport (HKIA) and a hospital. METHODS: Epidemiological investigations, patients' measles serology, and phylogenetic analysis of the hemagglutinin (H) and nucleoprotein (N) genes of measles virus isolates were conducted. RESULTS: In total, 29 HKIA staff of diverse ranks and working locations were infected with measles within 1 month. Significantly fewer affected staff had history of travel than non-HKIA-related measlespatients [10 of 29 (34.5%) vs 28 of 35 (80%); P < .01]. Of 9 airport staff who could recall detailed exposure history, 6 (66.7%) had visited self-service food premises at HKIA during the incubation period, where food trays, as observed during the epidemiological field investigation, were not washed after use. Furthermore, 1 airport baggage handler who was admitted to hospital A before rash onset infected 2 healthcare workers (HCWs) known to have 2 doses of MMR vaccination with positive measles IgG and lower viral loads in respiratory specimens. Infections in these 2 HCWs warranted contact tracing of another 168 persons (97 patients and 71 HCWs). Phylogenetic comparison of H and N gene sequences confirmed the clonality of outbreak strains. CONCLUSION: Despite good herd immunity with overall seroprevalence of >95% against measles, major outbreaks of measles occurred among HKIA staff having daily contact with many international pssengers. Lessons from severe acute respiratory syndrome (SARS) and measles outbreaks suggested that an airport can be a strategic epidemic center. Pre-exanthem transmission of measles from airport staff to HCWs with secondary vaccine failure poses a grave challenge to hospital infection control.
Authors: Shi Zhao; Xiujuan Tang; Xue Liang; Marc K C Chong; Jinjun Ran; Salihu S Musa; Guangpu Yang; Peihua Cao; Kai Wang; Benny C Y Zee; Xin Wang; Daihai He; Maggie H Wang Journal: Infect Drug Resist Date: 2020-06-17 Impact factor: 4.003
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