Archive 30: Summary of updates in the Canadian Immunization Guide of June 3, 2022: Updated guidance on COVID-19 vaccines in Canada [2022-06-03]

Published: June 3, 2022

Notice to reader

This is an archived version. Please refer to current COVID-19 vaccine pages:

Overview

On June 3, 2022, the Public Health Agency of Canada (PHAC) released updated guidance including several recent updates from the National Advisory Committee on Immunization (NACI) on the use of COVID-19 vaccines in the COVID-19 vaccine chapter of the Canadian Immunization Guide (CIG). This guidance is based on current evidence and/or NACI's expert opinion.

What you need to know

The COVID-19 vaccine chapter was updated based on the following statements from the National Advisory Committee on Immunization (NACI):

The following additional updates were also made:

  1. Guidance on the interval between multisystem inflammatory syndrome in adults (MIS-A) and COVID-19 vaccination was added to Table 5 and the Precautions section. This guidance aligns with the previously-noted guidance on the interval between multisystem inflammatory syndrome in children (MIS-C) and COVID-19 vaccination.
  2. Information on a Health Canada-authorized Janssen COVID-19 booster dose.
  3. A revised list of those considered to be moderately to severely immunocompromised in the Immunocompromised Persons section.
  4. Guidance on the re-vaccination with mRNA COVID-19 vaccines for those with thrombosis with thrombocytopenia syndrome (TTS) following vaccination with viral vector COVID-19 vaccines.

Supporting information

1. Guidance on the interval between MIS-A and COVID-19 vaccination

NACI was asked to clarify whether individuals with a history of multi-systemic inflammatory syndrome in adults (MIS-A) would be subject to the same guidance as in children (MIS-C).

After reviewing the published literature on the subject, the NACI Vaccine Safety Working Group discussed the issue and decided to provide the same recommendation for MIS-A and MIS-C. This recommendation was approved by NACI during a virtual meeting on April 26, 2022.

"For adults with a previous history of MIS-A, vaccination should be postponed until clinical recovery has been achieved or until it has been ≥ 90 days since diagnosis, whichever is longer."

Provided is the list of selected references that informed this guidance:

2. Information on a Health Canada-authorized Janssen COVID-19 booster dose

On May 11, 2022, Health Canada authorized the use of a booster dose of Janssen COVID-19 vaccine for individuals 18 years of age and older who have previously received a primary series with Janssen COVID-19 vaccine.

Clinical trials have shown that a booster dose of Janssen COVID-19 vaccine administered 56 days after the first dose was efficacious against moderate to severe/critical COVID-19.

Real-world evidence indicates that a booster dose of Janssen COVID-19 vaccine may not be as effective or immunogenic as a booster dose of an mRNA COVID-19 vaccine given as a homologous or heterologous booster.

A booster dose of Janssen COVID-19 vaccine is an option for individuals in whom all other COVID-19 vaccines are contraindicated.

Provided is a list of selected references that informed this guidance:

3. A revised list of those considered to be moderately to severely immunocompromised in the Immunocompromised Persons section

The list was reviewed and revised following requests for further clarification of the criteria. After reviewing the published literature on the subject, the CIG Part 3 Working Group on Vaccination of Specific Populations revised the list, as per below. The revisions were approved by NACI during a virtual meeting on April 26, 2022.

A range of factors can impact the relative degree of immunocompromise and response to COVID-19 vaccines, and clinical and public health judgement should be applied. Jurisdictions may modify the list based on population considerations.

Provided is the list of selected references that informed this guidance:

4. Guidance on the re-vaccination with mRNA COVID-19 vaccines for those with thrombosis with thrombocytopenia syndrome (TTS) following vaccination with viral vector COVID-19 vaccines

Clarification was needed regarding the re-vaccination of individuals with TTS following vaccination with viral vector vaccines. The NACI Vaccine Safety Working Group (VSWG) reviewed the literature, consulted with hematologists from McMaster University, the Special Immunization Clinic (SIC) Network, sought information from manufacturers of viral vector COVID-19 vaccines and discussed the issue. The following recommendation was presented by the VSWG to NACI during a virtual meeting on April 26, 2022 and approved.

"Patients who have experienced venous and/or arterial thrombosis with thrombocytopenia following vaccination with a viral vector COVID-19 vaccine should not receive a subsequent dose of a viral vector COVID-19 vaccine. They may receive further doses of mRNA COVID-19 vaccines following consultation with their clinical team which may include a hematologist."

Provided is the list of selected references that informed this guidance:

For more information on NACI's recommendations on the use of COVID-19 vaccines, please refer to the COVID-19 vaccine chapter in the Canadian Immunization Guide (CIG), as well as additional statements on the NACI web page.

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