new research from mcmaster university, aimed at understanding the immune response to covid-19 vaccines, found some long-term care residents no longer had high antibody levels months after their second dose, directly supporting government decisions to provide third doses.
the study, supported by the government of canada through its covid-19 immunity task force (citf), found over 97 per cent of residents produced an initial antibody response that is likely to provide protection against the virus.
three to five months after receiving their second dose, researchers found a drop in the antibody level in about 20 per cent of residents to the point where the antibody response may not be strong enough to provide effective protection against the virus.
“the vaccines have worked well in our nursing homes, but we need constant vigilance regarding how well vaccines and other measures are protecting vulnerable residents,” said andrew costa, co-lead of canada’s global nexus task force on long-term care crisis management and renewal and schlegel chair in clinical epidemiology and aging at mcmaster.
“the study continues to shed light on risks that might lie ahead.”
about 70 per cent of canada’s covid-19 deaths have occurred in long-term care or nursing homes.