John: Among the updated Cochrane Reviews in March 2016 is one from a team of researchers in Brazil looking at the effects of vaccines for Herpes Zoster. Anna Gagliardi from the Department of Geriatrics and Gerontology at the Federal University of São Paulo in Brazil describes their findings in this evidence pod.

Anna: Herpes Zoster or shingles is a neurocutaneous disease characterized by the reactivation of the zoster varicella virus, which is the same virus responsible for chickenpox or varicella.
When the chickenpox episode is over, the virus can remain dormant inside the nerves in the person's spine with its replication inhibited by specific immunity that the person acquired. However, if that immunity declines for any reason, the virus may reactivate and travel through the nerve to the skin surface, producing clusters of blisters along the path of the affected nerve, a condition called herpes zoster. This can be an extremely painful disease with symptoms such as itching, numbness, tingling or localized pain. It can precede the appearance of skin lesions.
The severe pain that some patients suffer arises from inflammation of sensory nerves and this, as well the other symptoms, can have important impacts on patients’ quality of life.
As people get older the specific immunity to varicella zoster virus tends to decline leaving the way open for viral replication, which predisposes elderly people to develop this disease. The older the person, the higher the incidence of herpes zoster.
However, herpes zoster can be prevented by a vaccine and our Cochrane Review provides an up-to-date estimate of its effects. The current vaccine for clinical use is composed of an attenuated virus and it is given by an injection under the skin. There is also a new vaccine, which is currently being tested but is not yet available for general use. This new vaccine contains a small part of varicella zoster virus plus substances that boost the immune response of the body.
Our updated review now includes thirteen studies with a total of nearly 70,000 participants. The studies were conducted in high-income countries and included only healthy elderly Caucasians, sixty years or over, without any immunosuppressive problems. Ten of the studies, which included 53,000 participants, are about the live attenuated varicella zoster virus vaccine. The other three studies that included 16,500 participants tested the new vaccine.
The evidence shows that the currently available live attenuated varicella zoster virus vaccine reduces herpes zoster in comparison with placebo during about three years of following up. The participants that received the vaccine were more likely to develop injection site adverse events, but these were mostly mild to moderate symptoms.
The studies about the new vaccine that is not yet available for clinical use showed that the participants allocated to the vaccine had fewer episodes of herpes zoster and more mild to moderate adverse events than those in the placebo group.
In conclusion, our review shows the effectiveness of vaccination for herpes zoster and the results of ongoing trials may add more relevant data to this interesting and important field of investigation.

John: To read this latest update of the Cochrane review, and to watch for further updates as the extra evidence becomes available, visit Cochrane Library dot com and run a search for 'vaccines for herpes zoster'.