The Topic of This Month Vol.23 No.5(No.267)

HIV/AIDS in Japan as of December 31, 2001

(IASR 2002; 23:109-110)

The HIV/AIDS surveillance began in 1984 and was conducted in compliance with the AIDS Prevention Law from 1989 through March 1999. Since April 1999, it has been continued as the National Epidemiological Surveillance of Infectious Diseases (NESID) under the Law Concerning the Prevention of Infectious Diseases and Medical Care for Patients of Infections (the category IV notifiable infectious diseases). For the HIV/AIDS reporting system, see IASR Vol. 19, No. 4, Vol. 20, No. 4, Vol. 21, No. 7 and Vol. 22, No. 5. The number of HIV-infected cases without AIDS (hereafter abbreviated to HIV cases) and that of AIDS patients in the current article are both based on the report as of February 27, 2002. The 2001 Annual Report confirmed by the National AIDS Surveillance Committee is going to be published by the Specific Disease Control Division, the Ministry of Health, Labour and Welfare (MHLW).

The trend of HIV/AIDS incidence 1985-2001: HIV cases newly reported in 2001 counted at 621 (534 males and 87 females) and AIDS patients at 332 (282 males and 50 females). Japanese males accounted for 76% of HIV cases and 67% of AIDS patients (Fig. 1). The reports of HIV cases once decreased in 2000 and then increased again to the largest number in 2001. Reports of AIDS patients have continuously been in the increase every year except 1998 (Fig. 2).

The cumulative number of reports from 1985 through December 31, 2001 (excluding those infected by use of coagulation factor products) counted at 4,526 for HIV cases and 2,246 for AIDS patients, corresponding to 3.566 HIV cases (3.087 until 2000) and 1.770 AIDS patients (1.512 until 2000) per 100,000 population. By another national survey, 1,430 HIV cases infected by use of coagulation factor products (including 150 AIDS patients) were reported as of May 31, 2000.

Nationality and gender: The recent increase in HIV cases is ascribable mainly to the increase in Japanese males, but Japanese females are also increasing gradually. Non-Japanese male cases are being kept on the same level or tending to increase slightly, but non-Japanese female cases are tending to decrease gradually (Fig. 3). For AIDS patients, Japanese males markedly increased during recent years, but slightly decreased in number in 2001. Since a decrease was also seen in 1998, and an increase followed, a careful observation seems necessary. Non-Japanese cases of both HIV cases and AIDS patients were dominant in Southeast Asia followed by Latin America and sub-Saharan Africa.

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 transmission are counted for less than 1%. Japanese male HIV cases due to homosexual contacts markedly increased (Fig. 3); homosexual contacts accounted for 63% and heterosexual contacts 26% in 2001. Japanese male HIV cases infected by homosexual contacts formed a peak at 25-29 years of age and an increase in cases in their 20s-30s are worthy of notice (Fig. 4a). The peak in age distribution of Japanese male HIV cases infected by heterosexual contacts is seen at the age of 30-34 years in 1999, 35-39 years in 2000, and 25-29 years in 2001 (Fig. 4b). That of Japanese females is seen at the ages of 25-29 years during 1998-2000 and 20-24 years in 2001 (Fig. 4c), being tending to shift to the younger generations.

Regions of acquiring infections: The majority of the Japanese have acquired infection within Japan (86% of HIV cases and 76% of AIDS patients). Both males and females of Japanese HIV cases having acquired infection within Japan tended to increase by 1999, slightly decreased in 2000, but then tended to increase again. Acquiring infection within Japan by non-Japanese males is also in the increase.

AIDS-defining diseases: The most common AIDS-defining diseases among AIDS patients in 2001 (245 Japanese and 87 non-Japanese) was Pneumocystis carinii pneumonia as previous years (113 and 32, respectively) followed by candidiasis (72 and 24, respectively). Other diagnosed diseases in Japanese cases were cytomegalovirus infection (in 28 patients), wasting syndrome due to HIV (in 27 patients), and active tuberculosis (in 26 patients), and those in non-Japanese cases were active tuberculosis (in 16 patients), wasting syndrome due to HIV (in 11 patients), toxoplasma encephalopathy (in 8 patients).

Deaths from AIDS: Deaths from AIDS reported before March 31, 1999 in compliance with the AIDS Prevention Law numbered at 596, including 485 Japanese (445 males and 40 females) and 111 non-Japanese (77 males and 34 females). From April 1999 through December 31, 2001, deaths reported to the Specific Disease Control Division, the MHLW by voluntary reporting counted at 126 including 101 Japanese (92 males and 9 females) and 25 non-Japanese (15 males and 10 females). Of these deaths, those reported in 2001 were 43 including 34 Japanese (30 males and four females) and nine non-Japanese (four males and five females).

HIV-antibody-positive rate among blood donors: The HIV-antibody-positives among blood donors continuously increased year after year, reaching the largest number ever recorded, being 79 (78 males and one female) of 5,774,269 donations or 1.368 per 100,000 donations (2.259 in males and 0.043 in females) in 2001 (Fig. 5). Since the HIV-antibody-positive rate among blood donors as compared with the reports of HIV cases is much higher than those in European and American countries (see IASR, Vol. 21, No.7), it seems necessary to call further attention of blood donors not to donate blood for the purpose of HIV testing.

HIV-antibody tests and counseling at health centers: HIV-antibody tests at health centers increased by 43% (21,183) from the preceding year to 69,937 tests in 2001 (including 34,867 simultaneous HIV- and HCV-antibody tests performed before the end of October in compliance with a notice by the Head, the Specific Disease Control Division, the MHLW, April 24, 2001) and the counseling cessions increased by 34,005 (about 32% increase) numbering at 141,271. These figures were considerably smaller than those of 1992, the largest ones ever recorded (135, 674 tests and 251,926 counseling cessions).

Conclusion: In 2001, both HIV cases and AIDS patients counted at the largest number ever reported and attention must be paid to the future trend. Special attention must be paid to the increase in HIV cases due to homosexual contacts among Japanese males and those due to sexual contacts among young generations of both Japanese males and females. The use of condoms to prevent HIV infection is highly effective, nevertheless it has been pointed out from the results of surveys on sexual behavior among young generation that the more sexual partners they have, the less frequently they use condoms (Kihara et al., Japan Medical Journal, 4066: 37-42, 2002). Contraceptive pills cannot prevent sexually transmitted infections (STIs). It is, therefore, necessary for the whole society to educate young people for the fundamental knowledge of HIV/AIDS that they must use condoms by all means and avoid risky sexual contacts to prevent such STIs as HIV/AIDS (see p. 112-116 of this issue).

It has been reported that, among HIV cases, the ratio of those whose infection was detected by HIV testing performed anonymously at health centers for free of charge is low (Hori et al., presented at a meeting of the Japanese Society for AIDS Research). To stop spreading HIV infection, early detection of HIV cases is urgently necessary. More active control measures for HIV/AIDS based upon the actual status in each district are being examined to increase HIV tests (see p. 116 of this issue). The simultaneous HCV and HIV testing performed in the last year was a good example of such new control measures that provide the opportunity for anyone to receive HIV tests as a part of health check-up (see p. 111&112 of this issue).

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