Mixing doses could also wind up being a useful approach in the months ahead, according to Dr. Christopher Labos, a Montreal-based cardiologist and epidemiologist. Typically giving a bit more time between a first vaccine dose and the second vaccine dose "really leads to a better overall immune response, and protection from whatever pathogen the vaccine was made against," noted Kelvin. A woman walks by a sign advertising for COVID-19 vaccines in Montreal on May 14. He also noted that preliminary results from a U.K. study suggest using different vaccines for different doses could even offer a "better immune response." "I think it was definitely a valid concern that all of the evidence we had for COVID-19 vaccines were based on the phase three clinical trials," she said.

Source: CBC News May 17, 2021 08:03 UTC