Updates
Updates
Genital Herpes Recurs Less Often, but Only in Half
Source: Benedetti JK, et al. Ann Intern Med 1999;131:14-20.
The frequency of reactivation of genital herpes infection was assessed in 664 non-HIV-infected patients with genital HSV infection enrolled in a prospective observational study for a minimum of 14 months. Patients were classified as having either newly acquired genital HSV (including 60 patients with primary HSV-1 infection and 246 with primary HSV-2 infection), or previously acquired (recurrent) HSV-2 infection (n = 358). About one-third of the patients received suppressive antiviral therapy for a median of 10 months during the study, and 38 patients with primary infection received acute antiviral therapy.
There was no evidence that the administration of antiviral therapy to persons with acute primary genital herpes decreased the rate of recurrences. There was also no evidence that pre-existing serologically documented HSV-1 infection affected the course of genital HSV-2 infection. During the first year of observation, the median recurrence rate was greatest for patients with existing vs. newly acquired HSV-2 infection (6 vs 5 per year), whereas patients with newly acquired genital HSV-1 had a median of one recurrence. Patients with HSV-2 infection experienced more frequent genital recurrences (97%) and infrequent oral outbreaks (1%), whereas patients with HSV-1 infection had 77% genital and 21% oral recurrences.
Between years 1 and 2, there was a significant decrease in the recurrence rate in persons who had had newly acquired infections at the time of enrollment. In contrast, persons with existing HSV-2 had only a minimal decrease in the frequency of outbreaks (0.2 fewer per year). Overall, however, only one-third had clinically meaningful decreases in the number of recurrences (³ 2 fewer), whereas another third had more outbreaks, indicating tremendous variability in the natural history of this infection. This variability continued through the first five years of observation: 50% of patients had at least two fewer outbreaks in year 5 compared with year 1, but 25% had more.
Given these figures, the need for chronic suppressive therapy in persons with recurrent genital HSV-2 should be reassessed every couple of years. Nearly half may be able to discontinue suppressive therapy in lieu of no therapy or only symptomatic treatment. Although frustrating, patients with recurrent genital HSV-2 should be reassured that frequent outbreaks are not unusual and that, while 50% of patients have fewer outbreaks over time, one-fourth may actually experience more. This should not cause undo alarm or trigger investigation of any underlying immune deficit.
New Improved HIV Assay
Source: Alaeus A, et al. AIDS Res Hum Retroviruses 1999;15:889-894.
While b clade hiv-1 infection predominates in the United States, other subtypes are common to other countries. An earlier report demonstrated the potential difficulties in determining plasma viral load for non-B clade HIV-1 subtypes using existing PCR-based assays (Kemper CA. Infect Dis Alert 1999;18:142-143); a young woman from Cameroon had substantially lower (and even undetectable) viral loads using an existing RT-PCR assay compared with the Chiron 3.0 b-DNA assay. Using molecular sequencing techniques, she proved to have a mosaic subtype B/D infection.
Alaeus and colleagues assessed the sensitivity of the new prototype Roche Amplicor HIV-1 (RT PCR) Monitor assay compared with the earlier first-generation assay. Stored specimens from 101 individuals with varying subtypes (28 A, 18 B, 26 C, 20 D, 2 E, 3 G, 2 H, and 2 J) were assessed. As anticipated, the results from the different assays were generally in good agreement with subtypes B and C, as well as for some subtype Ds. However, compared with the older assay, the newer assays detected significantly higher viral loads for patients with other subtypes (A, E, G, H), suggesting that the newer assays will be much more useful in detecting and monitoring HIV infection due to non-B subtypes.
British Travel Problematic for U.S. Blood Donors
Source:ProMED-mail, August 18, 1999. www.healthnet.org.
The canadian and u.s. govern-ments have announced new blood donor restrictions for frequent travelers to Britain prior to 1997 when restrictions on beef and cattle products went into effect. The ban specifically applies to individuals who have traveled to or resided in England, Scotland, Wales, Northern Ireland, the Isle of Man, and the Channel Islands for a total of six or more months between 1980 and 1997. Individuals with multiple trips to the British Isles will be required to add up the total number of days spent there. A total of 41 fatal cases of bovine spongiform encephalopathy have occurred in Britain and the United States. This bans the importation of beef from Great Britain. No cases of mad cow disease have been reported in the United States. But federal authorities say that scientists can not rule out the possible discovery of a future link between blood donation and subsequent illness due to this poorly understood disease. These restrictions are quite controversial and come at a time when the American blood banking system is already experiencing severe shortages.
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