An experimental vaccine by GlaxoSmithKline against shingles is proving to be effective in testing, as it offers lasting protection for most of the older adults who receive it.

Shingles is characterized by itchy and painful rashes that develop on one side of the body, caused by the reactivation of the dormant chicken pox virus. The risk of acquiring shingles increases as people grow older.

According to the latest results of clinical trials, the experimental vaccine, named Shingrix, remained 90 percent effective in adults with ages of over 70 years old even after four years from the intake of the vaccine.

The trials showed that Shingrix provides a better protection against shingles for older people compared with the Zostavax vaccine of Merck & Co.

The study, which was published in the New England Journal of Medicine, revealed that the two-dose Shingrix, administered two months apart, had 90 percent efficacy compared to placebo in people of over 70 years of age. In addition, the efficacy of the vaccine was maintained across the several age groups that were included in the clinical trials, ranging between 90 percent for participants with ages between 70 years and 79 years and 89 percent for participants with ages above 80 years.

The high efficacy demonstrated by Shingrix follows the results of a previous trial published last year, wherein the vaccine showed 97 percent efficacy in people with ages of over 50 years.

In summary, the pooled data analysis for both trials revealed a 91 percent efficacy for Shingrix in adults with ages of 70 years and above, with efficacy maintained with an 88 percent decrease in the risk of shingles after the fourth year from the time of vaccination. In 89 percent of the cases, Shingrix also protected patients against the residual pain caused by shingles.

In comparison, the efficacy of Zostavax declines on higher age groups, with only around 18 percent efficacy in adults over 79 years old compared with 70 percent efficacy in adults in their 50s. A study by Kaiser Permanente found that Zostavax had 69 percent efficacy in people over 60 years of age, but only 4.2 percent of the recipients remain protected after seven years.

GSK has high hopes for Shingrix to become a big new product for the company, with GSK planning to file for approval of the vaccine in the United States, Europe and Japan within the year. Shingrix should then become available to patients next year.

Analysts are expecting global sales of the vaccine to reach $1.2 billion by 2021.

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