Fullback Reggie Cannon, who plays for Portuguese side Boavista, extended the American lead on 52 minutes, showing great poise to pick his way through the Costa Rica defence to score.
The trip aims to put into practice President Joe Biden's desire to tackle issues driving migrant arrivals to the southern border of the United States, said Julie Chung, the acting assistant secretary of state for the Western Hemisphere.
World Health Organization boss Tedros Adhanom Ghebreyesus and United Nations Secretary-General Antonio Guterres have already made similar calls for equitable access to vaccines.
"It will help us leverage the budgetary gaps for 2021, 2022 and 2023" and help lower the highs costs associated with El Salvador's debt, Zelaya said.
"What (the ruling) New Ideas party and President Bukele achieved on Sunday is truly a golden opportunity for El Salvador's economy to take off," said Zelaya.
The US Department of Agriculture on Friday said private exporters reported the sale of 195,338 tonnes of corn to Costa Rica and 115,577 tonnes of corn to Guatemala.