This is a summary, written by members of the CITF Secretariat, of:
Breznik JA, Huynh A, Zhang A, Bilaver L, Bhakta H, Stacey HD, Ang JC, Bramson JL, Nazy I, Miller MS, Denburg J, Costa AP, Bowdish DME, other members of the COVID-in-LTC Investigator Group. CMV seropositivity in older adults changes T cell functionality, but does not prevent antibody or cellular SARS-CoV-2 vaccine responses. medRxiv. 2022 May 28. doi: 10.1101/2022.05.27.22275673.
The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.
A preprint, not yet peer-reviewed, affirms that infection with cytomegalovirus (CMV), which has been shown to influence immune competence in older adults, does not alter antibody and memory T cell responses to COVID-19 vaccination in older adults living in assisted-living facilities. CMV is a chronic and mostly asymptomatic viral infection that affects 60-90% of the adult population worldwide.
These findings emerged from the CITF-funded COVID-19 in Long-term Care Study, co-led by Drs. Dawn Bowdish and Andrew Costa, and a CIHR/CITF co-funded study award to Dr. Ishac Nazy, all based at McMaster University.
- Infection with CMV (CMV seropositivity) does not affect the production of antibodies against the spike (S) and receptor binding domain (RBD) proteins or on their neutralization of the original strain and Beta variant of SARS-CoV-2 in older adults.
- While CMV seropositivity does influence the composition of circulating T cells, it does not alter the ability of older adults to generate memory T cells nor their reactivation after COVID-19 vaccination.
The study included 188 older adults living in assisted-living facilities in Ontario. All were vaccinated with mRNA COVID-19 vaccines following the manufacturer’s recommended interval for the primary series. A third dose was received about six months following receipt of the second dose. Blood was collected between March and December 2021 at least one week following receipt of the second and/or third dose. 70% (131/188) of participants were positive for CMV antibodies (i.e., CMV seropositive).