 SAN FRANCISCO--BUSINESS WIRE--AllisonPartners announced today that health communications veteran Michelle Webb has joined the firm as managing director and North American health practice lead. Webb brings nearly 20 years of experience across a broad range of health companies, including Fortune 100s, startups, trade associations, and nonprofits. Michelle will be responsible for evolving the agencys health practice to create a more robust, cohesive and scalable offering. Shell report to Cath 