A vaccine that could protect against shingles in adults – Sanofi Pasteur MSD’s Zostavax – has been recommended for approval by the European Union’s Committee for Medicinal Products for Human Use (CHMP).

Shingles is caused by latent varicella zoster virus, the same virus that causes chickenpox, and can result in a blistering rash that can last for months or even years. In trials reported last year, Zostavax was able to reduce pain and discomfort in more than 60% of patients, cutting the incidence of persistent pain by two thirds. If approved, Zostavax would be the first vaccine for shingles to reach the market.

Zostavax has also been recommended for approval in the USA, where it is being developed by Merck & Co, although last month the US Food and Drug Administration delayed a decision on approving the vaccine until May 25 in order to review additional formation supplied by the company.

Analysts have suggested that although Zostavax could potentially be used by millions of people, it could take time for use of the vaccine to ramp up, as doctors will need to work out how best to incorporate it into clinical practice. Estimates are that the product will achieve sales of around $200 million by 2008. But with a million new cases of shingles occurring each year in the USA alone, its peak sales could be much higher.

GlaxoSmithKline is also developing a vaccine against zoster, but its candidate is still in Phase I development so remains some years away from the market.

Zostavax is one of four vaccines Merck is developing to help it tap into a global market estimated to grow from $8 billion in 2004 to $18 billion in 2008. The others are cervical cancer vaccine Gardasil, ProQuad, which protects against multiple paediatric infections, and Rotateq for rotaviral gastroenteritis.