Merck HPV vaccine Gardasil is poised for major growth by 2025 as new geographies and expanded labels add more people to its patient pool.

Although the vaccine is 12 years old, Wolfe Research analysts said in a note that it is at a “major inflection point.” The investment firm updated its estimates for Gardasil and said it could reach roughly $7 billion in sales by 2025. The consensus estimate has Gardasil under $5 billion by 2025.

Wolfe analysts said there are four factors driving the potential for increased sales: the vaccine is rolling out in new markets, like China; the label was recently expanded to include people aged 9 to 45; global health agencies are recommending the vaccine to both boys and girls; and messaging for the treatment was changed to show it prevents several types of cancer caused by human papillomavirus.

Publicis North America has worked on Gardasil campaigns, including Merck’s unbranded HPV effort in 2017.

Gardasil is Merck’s third-largest drug by sales. In Q3, it earned $1.05 billion, a 55% increase over 2017, placing it behind diabetes treatment Januvia and immunotherapy Keytruda on Merck’s roster.

The vaccine has a huge opportunity in China, where the potential market is up to 150 million women. Wolfe analysts estimated the Chinese market could be worth nearly $17 billion alone, even without expanding the vaccine population to include men.

Analysts say the biggest challenge for Merck is simply keeping up with demand. The company dedicated billions to increasing production of Gardasil, but it may take five years to maximize the production, analysts warned.

Because Gardasil is a vaccine, Merck doesn’t have to worry about losing its patent. The only competition is from GlaxoSmithKline’s Cervarix, which has little market share and covers fewer strains of HPV. GSK also pulled Cervarix from the U.S. market in 2016, and has since removed it from other markets like Australia, due to lack of commercial traction.

“Equally important to recognize is that there is no generic vaccine paradigm that threatens the longevity of this franchise,” the analysts wrote. “In other words, there is no ‘patent cliff’ to worry about with Gardasil. This means that [Merck’s] near-monopoly in the area of HPV vaccines should continue on almost in perpetuity, as least based on today’s commercial and regulatory dynamics. The runway for future growth of Gardasil appears to be a very long one.”