Scientists at the Howard Hughes Medical Institute (HHMI) are developing a herpes vaccine. Virion and membrane-bound virus-specific glycoproteins were solubilized with Nonidet P-40 and separated by ultracentrifugation. Many studies have shown that injectable contraceptives containing progestins may increase a woman’s risk of being infected with HIV and with HSV-2, the virus causing genital herpes. The reduction in plasma viral load at the end of the three month study was 0.5 log10, a decline associated with a reduction in the risk of disease progression, notes Dr Lawrence Corey of the University of Washington, Seattle, in an editorial accompanying the study report. Both are known to infect the body’s nerve cells, where the virus can lay dormant for years before symptoms reappear. In virus neutralization test higher antibody titre was found against homologous virus. In this study, the researchers examined the underlying mechanisms.
The authors speculate that reducing HSV-2 levels may reduce the activation of cells latently infected with HIV (HSV-2 can activate latent HIV), and discourages clinical episodes of herpes simplex that lead to an upsurge of HIV replication. Company officials developing a competing herpes vaccine noted that “High unmet medical needs exist for new treatments because existing treatments of acyclovir-based antivirals can temporarily reduce but not eliminate genital herpes, viral shedding, and transmission; these drugs have not appreciably impacted HSV-2 seroprevalence rates despite over 30 years of usage.” (See Stockhouse.com, from October 8, 2014) (2) In other words, traditional anti-herpes medications have not lowered the HSV infection rate in over 30 years, and these company officials are hopeful that vaccines in development will change this reality. Dr Philippe Mayaud, one of the researchers from the London School of Hygiene and Tropical Medicine who carried out the study, said: Our results have important potential implications for public health and clinical practice, as HSV-2 control could become a new form of HIV prevention targeting HIV-infected individuals, as well as providing clinical benefits. Most of the mice with the E2 pellets survived the challenge and showed much less severe disease symptoms. The development and evaluation of an HSV vaccine should rank high on the international research agenda.