As the first wave of COVID-19 begins to peak in Canada, it is important not only to marshal all resources to manage the immediate surge of patients, but also to anticipate what lies beyond the peak. Collecting data on the extent of COVID-19 infection in the population and in specific subgroups where exposure risk is higher (e.g. healthcare workers), will equip us for decisions on relaxing public measures.
Easy to use blood tests are becoming available that will support large serological surveys. Collecting blood samples from large numbers of people, including asymptomatic or mildly symptomatic people who did not seek healthcare, and testing them for antibodies to SARS-CoV-2 (serology testing) will provide the data needed to understand the scale of infection in Canada. Rapid and representative national surveys provide a snapshot of where we stand now, and what to expect in a possible second wave of infection.
Targeted sero-surveys on the levels and trends in immune status amongst public-facing workers or among children and youth can inform the best timing of decisions for safe return to work and to school. They can also shed light on the immunity status of vulnerable populations – Indigenous communities and residents of nursing homes and long-term care facilities. They can help to direct proactive preventive efforts with vaccines and disease-modifying or even disease-preventing therapies should they become available. And they inform targeted surveillance efforts to snuff out further outbreaks before they become epidemics.
Other countries are implementing sero-surveys. For example:
- Germany tested a community with a high rate of COVID-19 cases and found that 14 percent of residents had antibodies to the virus indicating previous infection even though these people were asymptomatic.
- The U.S. is recruiting volunteers who have not been diagnosed with COVID-19 to test for prior infection and determine the extent of undetected spread as well as to better understand which communities and populations have been most affected. The U.S. has also initiated sero-surveys in disease “hot-spots” and among health-care workers. Three national representative sero-surveys of the U.S. population will test blood donors – 50,000 in September and December of 2020 and in November 2021.
- The World Health Organization has launched Solidarity II to pool findings from large-scale antibody studies around the world according to a standardized data collection approach.