West Pharmaceutical Services Inc. is a Philadelphia-area company that most people have never heard of, but more often than not, one of its products is involved whenever someone gets a COVID-19 vaccine shot.

That’s because West’s leading products are rubber stoppers for vials that hold injectable medicines and rubber tips for syringe plungers. Even before the pandemic, the Exton company, one of many in the region that serve the pharmaceutical industry, manufactured more than 40 billion of those and other components each year.

But now demand has skyrocketed along with the push to vaccinate billions of people around the world against COVID-19 — to the point that the firm expects to generate $260 million in revenue this year just from COVID-19-related products. Last year’s overall revenue was $2.1 billion.

“We’re involved with basically all the vaccines that are in the market,” said Eric Green, West’s chief executive.

West is among the Philadelphia-area companies playing a background role in the massive rollout of COVID-19 vaccines. PCI Pharma Services in Northeast Philadelphia labels and repackages vials of vaccine that are likely sealed with West stoppers. In Montgomery County, Merck & Co. Inc. announced in March that it would help manufacture Johnson & Johnson’s COVID-19 vaccine, which has suffered manufacturing issues elsewhere and has been put on hold while the government sorts out blood-clot concerns.

Because of the increased demand, West is adding enough new equipment at factories in upstate Pennsylvania and North Carolina to double the company’s capacity for products used with vaccines. The first of the new machines — presses imported from central Europe that trim the molded plugs — were installed last year.

Additional machines are still being installed in Jersey Shore, Pa., and are expected to reach full-scale production in the next few months. Green, who wouldn’t say how many machines are being added, told Wall Street that the additions were already planned over the next five years, but moved up in response to the pandemic.

What’s the big deal about West’s rubber stoppers?

It’s the rubber’s coating, which prevents interaction between the vaccine or other medication and the man-made rubber. Without the coating, the drug might not work as designed.

“These are not just drop-in-the-box” items, said David Bergerstock, a West vice president. “These are manufactured in a clean-room environment. They are placed in ultraclean sterilizable bags, and in some cases they are steam sterilized.”

Wall Street has rewarded West handsomely for that expertise. The company is worth about $10 billion more than it was at the beginning of the pandemic early last year. Its shares closed Thursday at $310.95, up from about $130 in March 2020.

Even before the pandemic, West was doing well financially thanks to its leading position in the manufacturing of devices used to inject biological medicines. These require special care because they are often derived from living materials and are more sensitive to damage than traditional medications that are chemically synthesized.

West has a part in 7 of 10 injections anywhere in the world, the company said. “We’re involved with basically all the vaccines that are in the market,” Green said.

Green said one customer allows him to identify it and a specific product for which West makes an injector: Amgen’s Repatha, which is a treatment for heart disease.

Aptar Stelmi and Datwyler, a Swiss company that has a plants in Pennsauken and Middletown, Del., are West’s two main competitors. Datwyler recently told a Swiss newspaper that it is the second-biggest producer behind West of stoppers and other components needed for injections.

West, which got half of its $2.1 billion in revenue last year from overseas, employed 9,200 on Dec. 31. Of those employees, 1,200 are in Pennsylvania, including 600 at the Jersey Shore factory where production is exploding. A second factory, in Williamsport, employs 130. Many of the remaining Pennsylvania employees work at the Exton headquarters or in research and development there.

Most of the new jobs in Jersey Shore are for technicians and operators in the molding, trimming, and packing areas. Starting pay with no experience is more than $17 an hour, West said. The R&D division in Chester County looks for people with professional backgrounds in mechanical or biomedical engineering, plastics engineering, chemical engineering, and material science.

Investment analysts such as John Kreger at William Blair are wrestling with whether to expect a drop in business for West and similar companies after the first big push on COVID-19 vaccines is over. “We suspect there will be a need for ongoing boosters to cover future variants, but probably with a lower level of compliance,” Kreger wrote in a recent note to clients.

West has deep roots in Philadelphia’s manufacturing past.

An accountant named Herman O. West cofounded it at 1117 Shackamaxon St. in Fishtown in 1923 as a manufacturer of rubber grinding wheels used in the dental trade.

West got the idea to go into manufacturing, according to a company history, while handling the books for S.S. White Co., a Center City dental instrument manufacturer whose building still stands at 12th and Chestnut Streets. Early on, West and his partners manufactured droppers, plungers, and stoppers for the pharmaceutical industry. Insulin maker Eli Lilly & Co. was a major early customer.

West’s factories have moved away from the company’s Philadelphia roots, but it retains an important tie to its manufacturing past. West has been making many of the molds for its stoppers and plungers and the sharp tools that trim them into their final shape in the same company-owned shop on West Chester Pike in Upper Darby since the 1940s.

“It’s fantastic that they are able to maintain that in-house tooling capability,” said Bill Stockwell, chief executive of Stockwell Elastomerics, a Northeast Philadelphia company that works with similar materials as West but serves different sectors.

The 18 employees in West’s Upper Darby shop use high-tech machines to supply tooling for 16 of West’s 25 manufacturing sites, said Bergerstock, the West official who is the company’s global process engineer. A second shop in England supplies other factories.

“Everything starts with the steel,” he said.