AstraZeneca and Oxford University‘s COVID-19 vaccine produced a strong immune response in older adults, data published on Thursday showed, with researchers expecting to release late-stage trial results by Christmas, reported Reuters.

The Oxford-AstraZeneca COVID-19 vaccine candidate had been among the front-runners in global efforts to develop shots to protect against COVID-19, but rival drugmakers Pfizer, BioNTech and Moderna have in the past 10 days edged ahead, releasing data from late-stage COVID-19 vaccine trials that shows more than 90% efficacy.

Oxford University has set a target of 53 infections to start the interim analysis of its late-stage trial results, though “lots of cases” in its trial arms in Britain, South Africa and Brazil mean the exact number of infections reported could differ.

In Latin America, Brazil has seen cases surge. Brazil recorded 754 deaths on Wednesday, according to the media consortium. The moving average of deaths in the last seven days rose to 584, which confirms the upward trend.

Mexico’s health ministry on Wednesday reported 3,918 new confirmed coronavirus infections in the country and 502 deaths, bringing the official totals to 1,015,071 cases and 99,528 dead.

Due to the upward trend in the region, Panama’s government has authorized spending of $4.3 million to purchase 1.09 million doses of the vaccine being developed by AstraZeneca, the president’s office said on Wednesday.

The Central American nation has been working on multiple COVID-19 vaccine options for its population of 4.2 million, with President Laurentino Cortizo saying he wants to guarantee that each resident will have access to two doses, reported Reuters.