VZV, temporal arteritis
A recent observation is VZV might cause temporal arteritis. A 2015 study (Neurology. 2015; published online before print Feb. 18, 2015) showed 40% of patients with giant cell arteritis (GCA) had VZV identified by polymerase chain reaction, and if many tissue samples were obtained and stained, 74% of patients had VZV antigen in skip areas, Dr. Margolis noted.
“These results suggest, but do not prove, that VZV causes temporal arteritis,” he said. Another study (JAMA Neurol. 2015;72:1281-1287) showed VZV antigen in 64% of patients negative for GCA. Similar findings were published (Ophthalmology. 2015;122:2142-2145) for patients with anterior ischemic optic neuritis suspected of having temporal arteritis but with negative biopsies; 5 of 7 patients were positive for VZV.
Herpes zoster vaccine (HZV)
Zoster vaccine live (Zostavax, Merck) has been available for more than a decade, but most eligible people have not been vaccinated, Dr. Margolis said.
Though the vaccine is not perfect, results have decreased disease incidence and severity. The incidence of zoster has decreased by 51%, and the incidence of post-herpetic neuralgia has decreased by 67%. However, the vaccine probably needs to be repeated after 10 years because of reduced efficacy over time.
A second vaccine, a gE subunit vaccine in a novel adjuvant (HZ/su, GlaxoSmithKline), is causing excitement because of its increased efficacy compared with the first vaccine. While the vaccine has not yet received FDA approval and is currently unavailable, a phase III study (N Engl J Med. 2015;372:2087-2096) reported the vaccine had 97.2% efficacy in preventing shingles and was as effective in patients aged more than 70 years compared with the shingles vaccine in current use in which patients aged more than 70 years did not benefit as much as younger patients.
Torque teno virus (TTV)
This virus is highly prevalent in humans and is on the ocular surface. The virus reactivates in the blood during sepsis and organ transplantation. Not much is known about this virus, and its exact role in the pathogenesis of diseases is unknown.
However, in underscoring the virus’ importance, Dr. Margolis recounted the results of a study in Nepal conducted by his laboratory in which 30 of 32 vitreous taps from patients with seasonal hyperacute panuveitis were positive for TTV. Another study carried out by Russell Van Gelder, MD, found that sterile taps from patients with endophthalmitis were positive in 7 of 7 patients for TTV.