Masahiro Satake1, Masako Iwanaga2, Yasuko Sagara3, Toshiki Watanabe4, Kazu Okuma5, Isao Hamaguchi5. 1. Central Blood Institute, Japanese Red Cross, Tokyo, Japan. 2. Department of Frontier Life Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. Electronic address: masakoiwng@nagasaki-u.ac.jp. 3. Kyushu Block Blood Center, Japanese Red Cross, Fukuoka, Japan. 4. Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan. 5. Department of Safety Research on Blood and Biological Products, National Institute of Infectious Diseases, Tokyo, Japan.
Abstract
BACKGROUND: Human T-lymphotropic virus 1 (HTLV-1) infection has an especially high prevalence in Japan. Transmission has been confirmed in infancy through breastfeeding; however, little is known about the epidemiological aspects of new HTLV-1 infections later in life. We aimed to estimate the nationwide annual number of new HTLV-1 infections among adolescents and adults in Japan. METHODS: In this retrospective cohort analysis, we assessed new HTLV-1 infections of repeat blood donors aged 16-69 years between Jan 1, 2005, and Dec 31, 2006, in the Japanese Red Cross Blood Centres database. We used results of antibody tests done in repeat blood samples collected until Dec 31, 2011, to assess the number who seroconverted to HTLV-1. We calculated the incidence density by dividing the number of seroconverters by the number of person-years of follow-up, and then extrapolated densities to regional populations to estimate the annual number of new HTLV-1 infections. FINDINGS: We included 3 375 821 HTLV-1-seronegative blood donors (2 100 915 men and 1 274 906 women). Within a median follow-up of 4·5 years (IQR 2·3-5·8), 532 people (204 men and 328 women) had seroconverted. The incidence density was significantly higher in women (6·88 per 100 000 person-years; 95% CI 6·17-7·66) than in men (2·29 per 100 000 person-years; 95% CI 1·99-2·62; p<0·0001). The estimated annual number of new HTLV-1 infections was 4190 (95% CI 4064-4318) with 975 (914-1038) infections in men and 3215 (3104-3328) in women. INTERPRETATION: New HTLV-1 infections in adolescents and adults are an important public health concern in Japan and preventive strategies are needed to reduce new transmission. FUNDING: Ministry of Health, Labour, and Welfare of Japan; Japan Agency for Medical Research and Development.
BACKGROUND:Human T-lymphotropic virus 1 (HTLV-1) infection has an especially high prevalence in Japan. Transmission has been confirmed in infancy through breastfeeding; however, little is known about the epidemiological aspects of new HTLV-1 infections later in life. We aimed to estimate the nationwide annual number of new HTLV-1 infections among adolescents and adults in Japan. METHODS: In this retrospective cohort analysis, we assessed new HTLV-1 infections of repeat blood donors aged 16-69 years between Jan 1, 2005, and Dec 31, 2006, in the Japanese Red Cross Blood Centres database. We used results of antibody tests done in repeat blood samples collected until Dec 31, 2011, to assess the number who seroconverted to HTLV-1. We calculated the incidence density by dividing the number of seroconverters by the number of person-years of follow-up, and then extrapolated densities to regional populations to estimate the annual number of new HTLV-1 infections. FINDINGS: We included 3 375 821 HTLV-1-seronegative blood donors (2 100 915 men and 1 274 906 women). Within a median follow-up of 4·5 years (IQR 2·3-5·8), 532 people (204 men and 328 women) had seroconverted. The incidence density was significantly higher in women (6·88 per 100 000 person-years; 95% CI 6·17-7·66) than in men (2·29 per 100 000 person-years; 95% CI 1·99-2·62; p<0·0001). The estimated annual number of new HTLV-1 infections was 4190 (95% CI 4064-4318) with 975 (914-1038) infections in men and 3215 (3104-3328) in women. INTERPRETATION: New HTLV-1 infections in adolescents and adults are an important public health concern in Japan and preventive strategies are needed to reduce new transmission. FUNDING: Ministry of Health, Labour, and Welfare of Japan; Japan Agency for Medical Research and Development.
Authors: Ueriton Dias de Oliveira; Fred Luciano Neves Santos; Bernardo Galvão-Castro; Marco Aurelio Krieger; Nilson Ivo Tonin Zanchin Journal: J Clin Microbiol Date: 2021-03-19 Impact factor: 5.948