Table 1. Risk factors associated with severe outcomes for patients dispensed nirmatrelvir/ritonavir (PaxlovidTM), Canadaa, 2022.
| Risk factor | Percentage with severe outcomes | Odds ratio (95% CI) |
p-valueb |
|---|---|---|---|
| Immunosuppressed status | |||
| Immunosuppressed | 7.78 | 3.79 (3.28–4.37) | <0.0001 |
| Not immunosuppressed | 2.18 | Reference | |
| Vaccination status | |||
| Unvaccinated/incomplete primary series | 4.37 | 1.91 (1.62–2.26) | <0.000 |
| Primary series/primary series with one or more booster | 2.33 | Reference | |
| Age | |||
| 60 years and older | 2.69 | 1.64 (1.42–1.89) | <0.0001 |
| 0–59 years | 1.64 | Reference | |
| Sex | |||
| Male | 2.73 | 1.25 (1.12–1.39) | <0.0001 |
| Female | 2.20 | Reference | |
| Number of comorbidities | |||
| One or more | 2.92 | 1.97 (1.73–2.24) | <0.0001 |
| None | 1.50 | Reference | |
a Based on data from six reporting jurisdictions
b The p-values were obtained from Pearson’s Chi-squared test. Primary series was defined as either two doses of a vaccine with a two-dose schedule (e.g. mRNA vaccines) or one dose of a vaccine with a one-dose primary series (e.g. Janssen Jcovden® COVID-19 Vaccine). Incomplete primary series was defined as having received at least one COVID-19 vaccine but not meeting the requirements for being considered having completed the primary series as per information in immunization records. The term “immunosuppressed” was defined as individuals meeting the following criteria: receipt of treatment for solid tumours and hematologic malignancies (including individuals with lymphoid malignancies who are being monitored without active treatment); receipt of solid-organ transplant and taking immunosuppressive therapy; receipt of chimeric antigen receptor (CAR)-T-cell or hematopoietic stem cell transplant (within two years of transplantation or taking immunosuppressive therapy); moderate or severe primary immunodeficiency (e.g. DiGeorge syndrome, Wiskott-Aldrich syndrome, common variable immunodeficiency, Good’s syndrome, hyper IgE syndrome); advanced or untreated HIV infection; and/or active treatment with high-dose corticosteroids (i.e. 20 mg or more prednisone or equivalent per day when administered for two or more weeks), alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, tumour-necrosis factor (TFN) blockers, and other biological agents that are immunosuppressive or immunomodulatory