Harvard HIV/AIDS activists, donning bathing suits and carrying an inflatable pool, staged a protest Thursday morning calling on the pharmaceutical company Merck to join the Medicines Patent Pool.

The “pool party,” which coincided with World AIDS Day, urged Merck to join the program that is designed to reduce the costs of AIDS drugs in developing countries.

About 20 members of the Harvard College Global Health and AIDS Coalition, including both undergraduates and medical students, chanted and held signs outside of a pharmaceutical conference held at the Westin Copley Place Hotel starting around 8:30 a.m. A smaller group of students entered the conference earlier that morning to pass out flyers and ribbons to conference attendees and reconvened with the main group after being asked to leave by hotel security.

“This is a less aggressive infiltration,” said Alyssa Yamamoto ’12, an organizer of the demonstration.

“We’re more trying to be informative than invasive,” she added.

Protesters speculated that conference officials seemed to have previous knowledge of the demonstration, as hotel entrances were well-staffed with police officers and security officials. At one point, two officers emerged from the hotel and asked demonstrators to clear the steps in front of the main entrance.

“Merck knows about our campaign,” said Yamamoto, adding that she thought Merck held “internal conversations” about the previous demonstrations carried out by Harvard AIDS activists. Yamamoto added that after sustained pressure from the coalition, Merck agreed to meet with them in January 2012.

Harvard AIDS activists said they hope the meeting will increase pressure on Merck to relinquish patents on several of its HIV/AIDS drugs to the Medicines Patent Pool. The Pool opens up patented drugs to generic producers for sale in developing countries and compensates the original patent holders with royalties.

“We recognize that pharmaceutical companies are not solely responsible for solving the AIDS crisis, but there is a special role for these drug owners because drug prices in the developing world directly impact the availability of critical medicines,” said protester Nathan T. Georgette ’13, who wore swim trunks over his khaki slacks and sports coat.

Organizers planned Thursday’s protest to fall on World Aids Day, observed every year on Dec. 1.

“Typically, World Aids Day is a day of remembrance and mourning,” said Yamamoto. “We want to make sure it also sounds a call for action.”

Protesters maintained that Merck’s participation in the patent pool would have a dramatic impact on reducing AIDS mortality in developing countries.

“Lots of people throw around the term ‘life-saving’, but these medications literally save lives,” said Arjun A. Suri ’08, a Harvard Medical School student who sported a lab coat, stethoscope, and swim trunks. “They turn HIV from a death sentence into a manageable chronic illness.”