This is a summary, written by members of the CITF Secretariat, of:
McMillan B, Marquez AC, Gaultier GN, Bartlett SR, Skowronski D, Levings M, Steiner T, Zlosnik J, Krajden M, Morshed M, Sekirov I, Jassem AN, Sadarangani M. Prospective Evaluation of Immunity After COVID-19 Vaccines: The PREVENT-COVID Study.

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

Research from the CITF-funded PREVENT-COVID study by Drs. Agatha Jassem and Manish Sadarangani from the University of British Columbia confirms the findings of other studies and reinforces the effectiveness of dried blood spot (DBS) tests as a simple and accurate alternative to blood tests. The non-peer-reviewed results, in a poster presented at the annual meeting of the Canadian Association for Clinical Microbiology and Infectious Diseases (CACMID), found high levels of spike-specific SARS-CoV-2 IgG antibodies in adults up to four months following a two-dose vaccine regimen.

Key findings:

  • Neutralizing capacity of vaccine-induced antibodies was significantly lower against SARS-CoV-2 variants compared to the wild-type Wuhan variant.
  • Increase in age was found to be associated with decreased spike-specific SARS-CoV-2 IgG antibody concentrations.
  • No association between sex and antibody response was observed.

Results observed using DBS samples are in accord with previously published studies using blood serum. These results are useful because DBS sampling eliminates the need for trained medical personnel since they are self-collected, making it a more efficient method for community collection of blood samples. In addition, collection cards are stable at ambient temperature for up to two weeks, simplifying transportation. These results also inform on vaccine responses in older adults.

The study looked at samples from 688 participants over the age of 19 (mean age = 66 years). The analysis was conducted of paired samples collected one-month post-vaccine dose two, and then at monthly intervals for a further four months.

See the poster