Key Takeaways Gardasil sales dropped 40% in the first nine months of 2025 due to weak demand in China and Japan.Economic weakness in China and soft demand in Japan weigh on Gardasil's sales outlook.MRK's other vaccines, including ProQuad, Rotateq and Pneumovax 23, also saw sales decline.Merck (MRK) continues to face challenges with Gardasil, its second-largest product, which is a vaccine approved for the prevention of certain cancers caused by human papillomavirus. Though the vaccine’s sales rose consistent ...