With its highly effective COVID-19 vaccine in wide use around the world, Pfizer hardly is resting on its laurels.

A COVID-19 pill pioneered last year at the company’s Groton labs is now in clinical trials at its New Haven facility, Pfizer executives noted Wednesday during a Zoom presentation to members of the Chamber of Commerce of Eastern Connecticut.

The new oral antiviral agent, which works by blocking an enzyme that enables the COVID-19 virus to replicate, could help keep people from getting the disease as well as provide some relief from its effects, said John Burkhardt, a Pfizer senior vice president and head of the Groton labs.

“We’re developing it as quickly as possible,” he said.

Pfizer also is studying its COVID-19 vaccine’s use on ever younger segments of the population while ramping up production of the vaccine.

Jean Lee, vice president and head of portfolio and project management for Pfizer research and development, said the company believes it can deliver 2.5 billion doses of vaccine worldwide by the end of 2021 — substantially more than the 1.5 billion doses it had projected earlier. It’s also on track to provide the U.S. government with an additional 300 million doses by the end of July, which would be two weeks ahead of schedule.

The supply will enable the vaccination of up to 150 million Americans.

Having this week gained the U.S. Food and Drug Administration’s emergency-use approval of the vaccine for children 12 to 15 years old, Pfizer is studying the vaccine’s use among pregnant women and among three other age groups: 5 to 11 years, 2 to 5 years and two months to 5 years.

Lee described the pace of the clinical trials critical to Pfizer’s development of the COVID-19 vaccine.

With “unprecedented speed,” she said, Pfizer and its Germany-based partner, BioNTech, won emergency approval for U.S. use of the vaccine just seven months after U.S. trials began, a process that normally takes seven years. Pfizer monitored nearly 45,000 Phase 3 trial participants at 150 sites in six countries: the U.S., Brazil, Argentina, South Africa, Germany and Turkey.

Lee, who called the numbers “staggering,” said Pfizer generally has 50,000 participants enrolled in trials worldwide at any one time.

“One would stop and question, ‘Well how did you do this?’” Lee said. “The first thing I would say is that this was the No. 1 priority — for the company, across the pharma industry and with our regulators. Something that really helped us was that great collaboration with the FDA and health authorities throughout the world.”

“Meetings that we would normally wait months for ... we got it in hours,” she said.

Lee said Pfizer continues to watch a “subset” of the COVID-19 trial participants to gather information related to such unknowns as the need for booster doses.

b.hallenbeck@theday.com