Trial vaccine reduces shingles pain in older people
Shingles rash: often followed by pain |
Older people at risk of developing shingles (Herpes
zoster) and associated neuropathic pain may benefit from a vaccine currently under investigation, new data suggest.
US researchers randomised 38,546 adults aged over 60 years to receive
either a live attenuated varicella-zoster vaccine or placebo, and monitored
them for the development of shingles. Among those vaccinated, 315 cases
of shingles were confirmed compared with 642 among those given placebo.
Following positive diagnosis, the patients’ pain and discomfort
were measured repeatedly for six months, and the researchers used the
incidence, severity and duration of the associated pain and discomfort
to calculate the “burden of illness” in each group. They
found that administration of the vaccine reduced the burden of illness
by 61.1 per cent (P<0.001). The incidence of postherpetic neuralgia,
the neuropathic pain syndrome that persists or develops after the rash
has healed, was also reduced by 66.5 per cent through use of the vaccine
(P<0.001). The vaccine reduced the overall incidence of Herpes
zoster by 51.3 per cent (P<0.001).
The incidence and severity of shingles and postherpetic neuralgia increase
with age as a person’s immunity to the varicella-zoster virus decreases.
The researchers say that the vaccine boosts immunity to the virus, reducing
the morbidity of the condition. Low rates of adverse effects were reported
in the study.
However, since the investigational vaccine was at least 14 times more
potent than the current vaccine licensed to prevent varicella (Varivax;
Merck) the researchers say that the licensed vaccine cannot be recommended
to protect against the virus (New England Journal of Medicine 2005;352:2271). |
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