"We will not be selling our vaccine at cost, although it is premature for us as we're a long way from understanding the cost-basis," Julie Gerberding, chief patient officer for Merck, told the House of Representatives subcommittee on oversight and investigations in a virtual, off-site hearing.
Merck's has yet to begin human studies of its experimental vaccine, lagging the leading candidates.
Executives from Johnson & Johnson and AstraZeneca Plc testified that they will price their respective potential vaccines at no profit while the pandemic rages on.
Gerberding and a representative from Moderna did not comment on the price they have in mind for their vaccines at the hearing, which focused on efforts to develop a safe, effective and widely accessible vaccine against COVID-19, which has claimed 600,000 lives globally.
Pfizer Inc has said the company intends to make a profit from its potential coronavirus vaccine if approved. However, Pfizer Chief Business Officer John Young, testified: "We recognize that these are extraordinary times and our price will reflect that."
Unlike rivals Moderna and AstraZeneca, Pfizer has not received funding from the United States for its vaccine development.
Lawmakers questioned whether Pfizer had declined government funding so it could price the vaccine at a profit.
"We didn't access federal funding solely for the reason that we wanted to move the vaccine faster to the clinic," Young said.
AstraZeneca said its vaccine would be provided at no profit under its agreement with the United States for allocation of some 300 million doses.
More than 150 coronavirus vaccines using a variety of technologies are in development globally, with some two dozen already in human trials. The aim is to produce vaccines that can end the pandemic by protecting billions of people from infection or severe illness. Whether any will succeed or be available by the US government's stated goal of having one by late this year remains far from clear.
"Speed is important," Gerberding said of the vaccine development, "but we will not compromise scientific efficacy, quality, and above all, safety, despite the sense of urgency we all feel."