Pfizer’s Prevnar 13 and Merck & Co.’s HPV franchise Gardasil are the world’s best-selling vaccines, and China sales have been driving growth for both of them. Now, thanks to new approvals, they're facing competition in that very market.

Tuesday, Chinese drug regulators approved domestic drugmaker Walvax Biotechnology’s 13-valent pneumococcal conjugate vaccine and local firm Innovax’s bivalent HPV vaccine Cecolin.

But with demand surging—and Pfizer and Merck racing to keep up—there may be room for everyone.

Virtual Roundtable ESMO Post Show: Highlights from the Virtual Conference Cancer experts and pharma execs will break down the headline-making data from ESMO, sharing their insights and analysis around the conference’s most closely watched studies. This discussion will examine how groundbreaking research unveiled over the weekend will change clinical practice and prime drugs for key new indications, and panelists will fill you in on the need-to-know takeaways from oncology’s hottest fields. Register today. Save Your Spot

Despite pneumococcal disease's status as a leading cause of vaccine-preventable deaths in young children, Prevnar 13 has long been the only 13-valent blocker available for children younger than two, mainly because of complex conjugate technology. Merck’s polysaccharide vaccine Pneumovax 23 is only allowed in children two years or older.

And the Pfizer product has been selling up a storm in China. After an approval in late 2016 and an official launch the next year, China soon injected new life into the Pfizer stalwart, sold as Prevenar 13 in the country.

In fact, as Prevnar sales dropped 4% in the U.S. on lower government purchases for children and a dwindling catch-up pool of adults, its $1.77 billion haul outside the U.S. represented a 9% jump at constant currencies, “mostly due to higher volumes reflecting continued uptake following the 2017 launch in China,” the company said in its quarterly filing.

For Merck’s HPV offerings, the quadrivalent Gardasil followed GlaxoSmithKline’s bivalent Cervarix into China in 2017, and Gardasil 9 picked up its own nod mid-2018. Both Cervarix and the Innovax version cover serotypes 16 and 18.

In the first nine months of 2019, sales from the Gardasil franchise outside of the U.S. increased dramatically by 64% to $1.46 billion, “driven primarily by higher demand in the Asia Pacific region, particularly in China,” the New Jersey pharma said in its quarterly filing.

That demand has been so strong for both shots, in fact, it's continually outstripped supply and triggered shortages. And that suggests the homegrown vaccines might have room to move without stepping much on Merck and Pfizer's products.

RELATED: Merck siphons off Gardasil CDC supplies again as global sales surge

According to data from China’s National Institutes for Food and Drug Control—which is responsible for testing vaccine batches before release—about 8.7 million HPV shots were waved through in 2019 as of November.

In contrast, about 356 million Chinese women are suitable for the vaccine, and at an approved dosing of three shots per person, that's a one-billion-dose gap, local media reported. Some major cities have even adopted a lottery system to reserve immunizations.

During a Merck conference call in October, chief commercial officer Frank Clyburn said the company has started building two new bulk Gardasil manufacturing facilities to meet rising global demand. But that project won’t go online until at least 2023, he said.

In the case of pneumococcal vaccination, about 3.85 million doses of Prevnar 13 entered the Chinese mainland in 2018. Walvax is planning to produce at last 30 million doses of its version a year, Chairperson Li Yunchun said, as quoted by The Beijing News. Using a per-dose price of CNY 698 (about $100) and assuming a 15% penetration rate, analysts at Zhongtai Securities figured the China pneumococcal vaccine market could be worth CNY 7.1 billion ($1 billion).

Neither Prevnar 13 nor Gardasil is covered by national medical insurance in China.