Thailand HIV Subtype More Deadly Than Others
Two studies led by researchers at the Johns Hopkins Bloomberg School of Public Health found that people infected with HIV in Thailand die from the disease significantly sooner than those with HIV living in other parts of the world. According to the researchers, the shorter survival time measured in the studies suggests that HIV subtype E, which is the most common HIV subtype in Thailand, may be more virulent than other subtypes of the virus.
The first study followed 228 men over a 14-year period starting in 1991. All of the men were serving in the Thai military and were HIV-negative when they enrolled in the study. The researchers tested for HIV every six months to determine approximately when they acquired HIV. The men were also diagnosed at a time before combination antiretroviral drug therapy was available.
The researchers compared the group of Thai men to a group of similar HIV-positive men living in North America and Europe who were included in another study. The median time from HIV infection to death for the Thai men was 7.8 years compared to 11 years for HIV-positive men living in North America and Europe. The survival rate for the Thai men was also lower than studies of similar populations living in low- and middle-income countries in sub-Saharan Africa where subtypes A, C, D and G circulate. However, the shorter survival after HIV infection among persons in Africa infected with subtype D was similar to the survival among the Thai men.
“We were surprised to learn that the young military recruits from Thailand appeared to develop AIDS more quickly and have shorter survival after their HIV infection than persons in Africa who were carefully followed,” said lead author Ram Rangsin, assistant professor of Community and Military Medicine at Phramongkutklao College of Medicine in Bangkok. Rangsin conducted the research while studying at the Bloomberg School of Public Health. “Fortunately, the men who have survived after their infection are now receiving treatment with effective antiviral drugs and doing very well.”
For the second study, researchers followed a small group of male blood donors and their wives from 1992 to 2007. All of the men and women were determined to have acquired HIV fewer than two years prior to enrolling in the study. The median survival rate from infection to death was 7.8 years for the men and 9.6 years for the women. Again, the survival rate was lower than the 11 years reported for HIV-positive men in developed countries.
“The fact that both young military conscripts and blood donors and their wives in Thailand had similarly shortened survival compared to persons in the U.S. and Africa–except those infected with subtype D viruses—suggests that viral subtypes D and E may be more virulent than many other viral subtypes,” said Kenrad E. Nelson, MD, a senior author of both studies and professor in the departments of Epidemiology and International Health at the Bloomberg School. “If we could understand better the virulence characteristics of these viruses, we might learn something more about why those with HIV infection progress to AIDS, usually many years after they are infected.”
AIDS. 21 Suppl 6:S39-S46, November 2007.
The natural history of HIV-1 subtype E infection in young men in Thailand with up to 14 years of follow-up.
Rangsin, Ram a; Piyaraj, Phunlerd b; Sirisanthana, Thira c; Sirisopana, Narongrid d; Short, Onsri c; Nelson, Kenrad E e
Objective: We evaluated the progression to AIDS and death among 228 men who seroconverted within a 6-month window when in the Royal Thai Army between 1991 and 1995.
Design and methods: Men (N = 228) who seroconverted to HIV at 21-23 years of age between 1991 and 1995 were evaluated up to 14 years after HIV seroconversion. The seroconverters were matched with men who were seronegative when they were discharged from the military. In 2005-2006, the vital status was determined through the national mortality database and survivors were contacted for follow-up clinical and immunological assessment. Death certificates, medical records and next of kin interviews were used to evaluate the causes of death.
Results: As of March 2006, among 228 seroconverters, 56 (24.6%) were alive, 171 (75.0%) had died and one (0.4%) had undetermined status. Among 255 HIV-seronegative individuals at baseline, 15 (5.9%) had died. The median time from HIV seroconversion to death was 7.8 years. The median time to AIDS death was 8.4 years. The median times from seroconversion to clinical AIDS and a CD4 cell count less than 200 cells/[mu]l were 7.2 years and 6.5 years, respectively. The median time from seroconversion to World Health Organization criteria for antiretroviral therapy was 6.3 years.
Conclusion: Our data indicate a more rapid progression to AIDS and death after HIV-1 infection among young Thai men than has been reported in similar aged men who were HAART-naive in western high income countries.
(C) 2007 Lippincott Williams & Wilkins, Inc.
AIDS. 21 Suppl 6:S47-S54, November 2007.
Survival of blood donors and their spouses with HIV-1 subtype E (CRF01 A_E) infection in northern Thailand, 1992-2007.
Nelson, Kenrad E a; Costello, Caroline b,d; Suriyanon, Vinai c; Sennun, Supaluk c; Duerr, Ann b,e
Objectives: To evaluate the survival patterns among adults in Thailand 8-14 years after HIV-1 subtype E (CRF01 A_E) infection.
Design: Follow-up for the current vital status of adults who were estimated to have had incident HIV-1 subtype E infection 8-14 years previously.
Methods: Data on the survival of a population of HIV-1-infected male blood donors and their seropositive wives was obtained during March-April 2007. These subjects were identified from a subpopulation of 150 individuals whose seroconversion interval was estimated to be less than 2 years and who were enrolled in 1992-1997. National registration, vital records, and death certificates, as appropriate, were obtained and Kaplan-Meier survival curves were constructed for the entire population, for males and females, and for individuals above and equal to or below the median age at infection.
Results: The vital status was obtained for 138 of 150 subjects (92%). The overall median survival was 8.2 [95% confidence interval (CI) 7.1-9.4] years. The median survival did not differ significantly between men and women or in those above or below the median age.
Conclusion: The median survival of 8.2 years in this population of young adults in Thailand was significantly less than that reported among persons of similar age in high-income countries or in eastern or southern Africa. The survival among individuals in Thailand infected with HIV-1 subtype E appears to be similar to that reported among individuals in Africa infected with HIV-1 subtype D.
(C) 2007 Lippincott Williams & Wilkins, Inc.