国立感染症研究所

 

The Topic of This Month Vol. 33, No. 9 (No. 391)


HIV/AIDS in Japan, 2011
(IASR 33: 229-230, September 2012)

 

HIV/AIDS surveillance in Japan had been conducted in compliance with the AIDS Prevention Law from 1989 to March 1999.  Since April 1999, however, it has been conducted in compliance with the Infectious Diseases Control Law that obliges doctors to notify all the diagnosed cases (criteria of reporting are found in http://www.mhlw.go.jp/bunya/kenkou/kekkaku-kansenshou11/01-05-07.html).  The data presented below are derived from the final version (March 28, 2012) of the annual report of the National AIDS Surveillance Committee for year 2011 released by the Specific Disease Control Division, the Ministry of Health, Labour and Welfare (MHLW) (http://api-net.jfap.or.jp/status/2011/11nenpo/nenpo_menu.htm).   It is important to note that the HIV surveillance in Japan counts as an “HIV case” an infected case that is detected by laboratory diagnosis before development of AIDS, and as an “AIDS case” an infected case detected by the manifestation of AIDS symptoms.   An HIV infected case once registered as an HIV case is not registered as AIDS case even if he/she subsequently develops AIDS.

1. Trend of HIV and AIDS cases reported during 1985-2011: The number of reported HIV cases in 2011 was 1,056 (994 males and 62 females), which was the fourth highest since start of the surveillance, following 1,126 in 2008, 1,082 in 2007 and 1,075 in 2010.   The number of reported AIDS cases was 473 (440 males and 33 females), which was the highest since the start of the surveillance (Fig. 1).   Cumulative number of HIV since 1985 to 2011 (excluding infections through administration of coagulants) amounts to 13,704 (11,564 males and 2,140 females) and that of AIDS to 6,272 (5,604 males and 668 females), which are equivalent to 10.723 and 4.908 per 100,000 population, respectively.   HIV cases that later developed AIDS symptoms or deceased are reported as “change in clinical condition*.”  Number of cases reported as such to Specific Disease Control Division, MHLW in 2011 was 6 for the former category and 16 for the latter category.   They were all Japanese males.   The “Nationwide Survey of Blood Coagulation Anomalies” has additionally identified total 1,439 coagulation factor products-related HIV infections (no increase since 2008), which includes 164 AIDS patients alive and 674 cases deceased (as of May 31, 2011). 

Nationality and gender: In 2011, 923 in total 1,056 HIV cases and 419 in total 473 AIDS cases were Japanese males (87% and 89%, respectively) (Figure).   These figures were slightly less than in 2010, which were 956 and 421, respectively.   HIV cases other than Japanese males were 42 Japanese females, 71 non-Japanese males and 20 non-Japanese females.   AIDS cases other than Japanese males were 16 Japanese females, 21 non-Japanese males and 17 non-Japanese females. 

Infection route and age distribution: Among Japanese male HIV and AIDS cases, infection through homosexual (including bisexual) contact was the most frequent (Fig. 2).   In 2011, 74% of Japanese male HIV cases (686/923) were through this route.   As for age distribution of this group, the most frequent was 30’s followed by 20’s (249 and 246, respectively); those in their 30’s have been continuously decreasing with the peak in 2008 (290 cases), and those in their 20’s have never exceeded the peak level of 2008 (252 cases) (Fig. 3a).   In 2011, however, a male homosexual HIV case in age group of 10-14 years was reported for the first time in Japan, which may be an alarming sign of spread of HIV to younger generation.   Among Japanese male AIDS cases, infection through the homosexual route occupied 61% (255/419), and such cases were frequent among 30’s (85 cases) and 40’s (79 cases); those in their 30’s decreased in the past two successive years, but those in their 40’s increased remarkably since 2009 (Fig. 3b).   Majority of Japanese female HIV and AIDS cases acquired infection through heterosexual contact.   There were 5 HIV/AIDS cases related to intravenous drug abuse (3 Japanese and 2 non-Japanese) in 2011 (7 cases in 2010), and additional 9 cases (all Japanese) having equal chance of infection through intravenous drug abuse and sexual contact (12 cases in 2010).   Though mother-to-child infection was not reported in 2007-2009, 3 cases were reported in 2010 and 1 case in 2011.

Suspected place of infection: For Japanese, in 2011, 91% of HIV cases (92% for male and 81% for female) and 81% of AIDS cases (81% for male and 75% for female) were presumably infected in Japan.   For non-Japanese HIV males, number of HIV infection in Japan exceeded that of the infection outside Japan in 2001.   Since then, this situation has remained unchanged.   In 2011, 51% of non-Japanese HIV males were infected in Japan. 

Districts where doctors made notification: Generally speaking, Kanto-Koshinetsu, Tokai, and Kinki areas reported larger numbers of HIV and AIDS cases compared with other regions.   Reports from Kanto-Koshinetsu (except Tokyo), Tokai and Kyushu increased.   When prefectures are compared for incidences of HIV and AIDS cases (Table 1), Tokyo, Osaka and Aichi continued to be the top three though they reported less numbers of cases in 2011 than 2010.   It should be noted that less populated prefectures began to report more HIV and AIDS cases in recent years (see incidence per 100,000 population). 

2. HIV-antibody-positive rates among blood donors: In 2011, there were 89 HIV-positives among 5,252,182 donated blood specimens (81 from males and 8 from females), which were equivalent to 1.695 positives (2.251 for males and 0.484 for females, respectively) per 100,000 blood donations, slightly exceeding the level of 2010 (1.617) (Fig. 4). 

3. HIV antibody tests and consultation provided by the local governments: The number of people receiving the HIV tests at health centers and other facilities provided by the local governments decreased in 2009-2010.   The number in 2011 was 131,243, maintaining the same level of 2010 (130,939) (Fig. 5).   There were 462 HIV positives corresponding to 0.35% of the tested samples (0.36% in 2010).   While the HIV positive rate among samples tested in health centers was 0.27% (281/102,946), the positive rate among samples from facilities other than the health centers, to which the risk groups are more accessible, was 0.64% (181/28,297), significantly higher than in health centers.   The number of counseling provided by the local governments has decreased in successive 3 years (163,006 in 2011 in contrast to 164,264 in 2010).

Conclusion: The number of AIDS cases reported in 2011 was the largest since the HIV/AIDS surveillance started.   Most HIV/AIDS cases are Japanese male homosexuals who were infected in Japan.   The age group with highest incidence for HIV cases is 20-30 year olds, and that for AIDS cases is 30-40 year olds.   Geographically, Tokyo, Osaka, Aichi and their surrounding areas continue to report large number of HIV/AIDS cases and more recently other areas including Kyushu area started to report increasingly.   In spite of these alarming situations, the number of people using the testing supported by local governments is declining since 2008.   Based on the current trend of HIV/AIDS epidemic, the central and local governments should take effective measures for preventing further spread of HIV and for detecting patients in early phase of infection so as to make possible early start of HIV therapy.   Effective preventive measures may include providing HIV testing and medical consultations more accessible in time and place to male homosexuals (particularly, in their 20’s-40’s) and other risk groups (young people, commercial sex workers and their clients, etc).   It is advised to consider possible collaboration with appropriate partners, such as, companies, NGOs, and educational and/or medical staff.   Ethical consideration is important for some of such activities. 

 
*“Change in clinical condition” includes development of AIDS symptoms among those once reported as HIV case and fatal consequence among those who had been reported as HIV case or as AIDS case.   They are reported to the MHLW on voluntary basis.

Copyright 1998 National Institute of Infectious Diseases, Japan

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