The Topic of This Month Vol.24 No.9(No.283)

HIV/AIDS in Japan, 2002

(IASR 2003; 24:203-204)

The HIV/AIDS Surveillance was started in 1984 and was conducted in compliance with the AIDS Prevention Law from 1989 through March 1999. Since April 1999, it has been conducted as the National Epidemiological Surveillance of Infectious Diseases (NESID) (the category IV notifiable infectious diseases) under the Law Concerning the Prevention of Infectious Diseases and Medical Care for Patients of Infections (see IASR, Vol. 19, No. 4, Vol. 20, No. 4, Vol. 21, No. 7, and Vol. 22, No. 5 for the reporting system and the guideline). The number of HIV-infected persons without AIDS (hereafter abbreviated to HIV cases)* and AIDS patients* in the current article are both based on the 2002 Annual Report by the National AIDS Surveillance Committee (the data were confirmed on February 27, 2003). The 2002 Annual Report has been published by the Specific Disease Control Division, the Ministry of Health, Labour and Welfare (MHLW).

1. The trend of HIV/AIDS incidence 1985-2002: HIV cases newly reported during 2002 counted at 614 (536 males and 78 females) and AIDS patients counted at 308 (268 males and 40 females). Japanese males accounted for as high as 78% of HIV cases (76% in 2001) and 75% of AIDS patients (67% in 2001) (Fig. 1). The reports of HIV cases once decreased in 2000 but increased again in 2001 attaining the largest number ever reported, and in 2002 the number was the second largest, although smaller than 2001 by seven. The number of AIDS patients in 2002 was somewhat less than that in 2000 and 2001, but it did not seem on a decreasing tendency (Fig. 2).

The cumulative number of reports from 1985 through December 31, 2002 (excluding those infected by use of coagulation factor products) counted at 5,140 for HIV cases and 2,556 for AIDS patients, corresponding to 4.050 HIV cases (3.566 until 2001) and 2.014 AIDS patients (1.770 until 2001) per 100,000 population. By a national survey independent of NESID, 1,431 HIV cases infected by use of coagulation factor products (including AIDS patients of 167 alive and 536 dead) were reported as of May 31, 2001.

Nationality and gender: The recent increase in HIV cases is ascribable mainly to the increase in Japanese male cases, but Japanese female cases are still continuing the upward tendency. Non-Japanese male cases are being kept on the same level or on a gradual increase but non-Japanese female cases are on a slow decrease (Fig. 3). For AIDS patients, increase in Japanese males is marked, although a slight decrease was noted in 2001, but again an increasing tendency was noted in 2002.

Mode of infection and age distribution: Both HIV cases and AIDS patients are infected principally by sexual contacts. Intravenous drug abuse and mother-to-child infection accounted for less than 1%. Japanese male HIV cases due to homosexual contacts markedly increased (Fig. 3), homosexual contracts accounted for 63% and heterosexual contacts 27% in 2002. The ages of Japanese male HIV cases infected by homosexual contacts formed a peak cumulatively at 25-29 years but the increased reports of cases of 20s during 2000-2001 are noticeable (Fig. 4a). The peak ages of Japanese male HIV cases infected by heterosexual contacts were 25-29 in 2001 and 30-34 in 2002, the reports in those age groups are increasing compared with before (Fig. 4b), the corresponding peak was at 25-29 years in 1998-2000 also in Japanese females, it was at 20-24 years in 2001 tending toward younger generations than before, and that in 2002 was not clear (Fig. 4c).

Of Japanese HIV cases infected by heterosexual contacts, a small number of females were reported during 1998-2002, but there were more females than males among 15-19 years (67%) and 20-24 years (58%), which was largely different from other age groups (Fig. 5).

Regions of acquiring infection: The greater parts of Japanese cases acquired infection within Japan (84% of HIV cases and 71% of AIDS patients reported in 2002). Of HIV cases acquiring infection within Japan, Japanese males are on the increase, while Japanese female and non-Japanese male cases are being kept on the same level or on a gradual increase. Of AIDS patients, Japanese male cases acquiring infection within Japan used to be on the increase, but were on the same level for the past three years.

2. Deaths from AIDS: Deaths from AIDS reported before March 31, 1999 counted at 596, including 485 Japanese (445 males and 40 females) and 111 non-Japanese (77 males and 34 females). Deaths reported voluntarily to the Specific Disease Control Division, MHLW, in the case-follow-up data (HIV¨AIDS, alive¨death) during April 1999-December 31, 2002, included 124 Japanese (115 males and 9 females) and 27 non-Japanese (16 males and 11 females), totaling at 151, of which 23 were Japanese (23 males and 0 female) and two non-Japanese (one male and one female) totaling 25 in 2002.

3. HIV-antibody-positive rate among blood donors: The HIV-antibody positive rate of blood donors is increasing year after year, being 82 (77 males and 5 females) among 5,784,101 donations in 2002, being 1.418 (males 2.215 and females 0.217) per 100,000 donations, which was higher than that in 2001 (being 1.368 per 100,000 donations) and the highest ever reported (Fig. 6). It seems necessary for blood donors to call more attention not to donate blood for the purpose of HIV testing.

Conclusion: Although reports of HIV/AIDS in 2002 were both slightly fewer than those in 2001 the largest number ever seen, a general tendency of increase due mainly to sexual contacts is still seen. Further attention is necessary for the future trend. Increase in HIV cases due to homosexual contracts among males requires further attention and active countermeasures. In the 2002 reports of the Research Group for socio-epidemiology on the trend of and intervention to prevent HIV infections (headed by Kihara, M.) according to the Working Group on prediction of HIV-infected cases and AIDS patients among Japanese in the near future (headed by Hashimoto, S.), HIV-infected persons through either infection route have increased rapidly, and it is predicted that HIV-infected persons without AIDS will become 22,000 by the end of 2006 (2.1 times more than the estimated number by the end of 2001) and the cumulative number of AIDS patients will become 5,000 (2.9 times the estimated number by the end of 2001). According to the Working Group on medical expenses for HIV/AIDS (headed by Hashimoto, S.), the cost of yearly medical expenses of HIV/AIDS in 2000 was estimated at \11,200,000,000. Future increase of patients accompanying increase in medical expenses is anticipated and preventive measures will become more important. For prevention of HIV/AIDS, instruction of fundamental knowledge of HIV/AIDS and other sexually transmitted infections (STIs), particularly to young people, understanding HIV/AIDS, avoiding sexual contacts with many unspecified persons, use of condoms to prevent STIs seem necessary (see p. 205-207 of this issue).

*(1) Report of AIDS patients: These are reports of HIV cases with AIDS-defining diseases already developed at diagnosis. They might not notice their HIV infection before development of AIDS.

(2) Report of HIV-infected: Reports of those whose infection became clear by a chance (blood test, consultation of a hospital, or blood donation) during the incubation period (average 10 years) after HIV infection and before developing AIDS-defining disease (see IASR, Vol. 23, No. 5). Once reported as HIV-infected, they may not be reported as AIDS patients even developing AIDS-defining disease later (in this case, reported voluntarily as separate case-follow-up data). HIV/AIDS reports, therefore, reflect the infection status during the past 10 years and the opportunity to receive HIV testing, not indicating the real-time infection status.

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