Wyeth Lederle has begun clinical trials for a new anti-diarrhoea vaccine in the country. This was announced by Baldev Arora, managing director, Wyeth Lederle, at the company's annual general meeting held in Mumbai yesterday.Called Rotashield, the vaccine is part of Wyeth's parent firm, American Home Products' portfolio, and has recently secured FDA approval.The vaccine is for children below the age of two, and provides protection against diarrhoea caused by the rota virus.