Canada has had measles elimination status since 1998 but remains vulnerable to outbreaks
Increased measles activity globally raises the risk of travel-related cases in Canada, which can spread rapidly in underimmunized communities.
The aims of this rapid systematic review are to synthesize evidence on the prevalence, levels, and durability of the antibody response to SARS-CoV-2 infection among adults and how antibodies correlate with protective immunity. Given the rapidly evolving evidence within this field, the Agency for Healthcare Research and Quality’s Evidence-based Practice Center (AHRQ EPC) Program will maintain this report as a living review with planned ongoing literature surveillance and critical appraisal. We will provide regular report updates as additional evidence becomes available, modifying the scope of the review as new directions in SARS-CoV-2 immunity research emerge. This review was conducted in coordination with the American College of Physicians (ACP) as part of AHRQ’s standing work to provide health professional organizations and systems with evidence reviews to support the development of clinical guidance for their clinician members.
The coronavirus disease 2019 (Covid-19) pandemic has claimed an estimated 15 million lives, including more than 1 million lives in the United States alone. The rapid development of multiple Covid-19 vaccines has been a triumph of biomedical research, and billions of vaccine doses have been administered worldwide. Challenges facing the Covid-19 vaccine field include inequitable vaccine distribution, vaccine hesitancy, waning immunity, and the emergence of highly transmissible viral variants that partially escape antibodies. This review summarizes the current state of knowledge about immune responses to Covid-19 vaccines and the importance of both humoral and cellular immunity for durable protection against severe disease.
Understanding immune responses to severe acute respiratory syndrome coronavirus 2 is crucial to understanding disease pathogenesis and the usefulness of bridge therapies, such as hyperimmune globulin and convalescent human plasma, and to developing vaccines, antivirals, and monoclonal antibodies. A mere 11 months ago, the canvas we call COVID-19 was blank. Scientists around the world have worked collaboratively to fill in this blank canvas. In this Review, we discuss what is currently known about human humoral and cellular immune responses to severe acute respiratory syndrome coronavirus 2 and relate this knowledge to the COVID-19 vaccines currently in phase 3 clinical trials.
