2 February 2023

Administration of COVID-19 booster doses: Recommendations for winter and spring 2023

  • This document presents the recommendations of the Comité sur l'immunisation du Québec (CIQ) regarding the direction the COVID-19 vaccination program should take in the winter and spring of 2023 to efficiently achieve its objectives.
  • Since the beginning of the vaccination program, the primary objective has been the protection of the most vulnerable persons and the prevention of severe disease and death due to COVID-19.
  • Vaccines against COVID-19 remain an essential tool given their effectiveness in preventing severe infections, primarily those leading to hospitalizations or death.
  • Individuals with hybrid immunity, following a first episode of COVID-19 and the administration of at least 2 doses of mRNA vaccines, have strong protection against hospitalization due to COVID-19.
  • Vaccinated individuals who have never been infected have less protection against hospitalization due to COVID-19 and this protection decreases over time. 
  • The…
Comité sur l'immunisation du Québec
18 February 2021

Preliminary Data on Vaccine Effectiveness and Supplementary Opinion on the Strategy for Vaccination Against COVID-19 in Quebec in a Context of Shortage

The Ministère de la Santé et des Services sociaux (MSSS) recently asked the CIQ to issue an opinion on the target interval before administration of the second dose, and important considerations to be taken into account for decision-making. The purpose of this opinion is to answer this question through an analysis of the most recent data on COVID-19 vaccine effectiveness from Quebec and abroad.


The data available on the efficacy of mRNA vaccines against COVID-19 in Phase 3 studies (clinical studies) and their effectiveness in studies monitoring the rollout (public health programs) remain limited at present time. It is, however, possible to identify certain preliminary trends:

  • The VE of a single dose of mRNA vaccines against COVID-19 appears high in the short term. It is likely that field effectiveness would be lower than the efficacy demonstrated in Phase 3 studies (92 %), one reason being that clinical trial participants are younger and in bett…
Comité sur l'immunisation du Québec
20 January 2021

Requested supplement to the notice Strategy for Vaccination Against COVID-19: Postponement of the Second Dose in a Context of Shortage

Recently, various strategies have been recommended in a number of jurisdictions regarding the time interval between the two doses of COVID-19 vaccines. The Ministère de la Santé et des Services sociaux (MSSS) has asked the Comité sur l'immunisation du Québec (CIQ) to explain the basis of these different intervals. The MSSS also inquired whether the CIQ has maintained the recommendations that it put forward in a recent scientific notice (1), in particular, the recommendation to offer an initial dose of the vaccine to the greatest number of individuals belonging to the first six priority groups1 before administering the second dose.


Data on certain approved vaccines

The Phase 3 trials on COVID-19 vaccines were carried out in a context where the objective was to very quickly obtain protection that meets the authorization criteria of the Food and Drug Administration and the World Health Organization (…

Comité sur l'immunisation du Québec
31 December 2020

Strategy for Vaccination Against COVID-19: Postponement of the Second Dose in a Context of Shortage


The number of cases, hospitalizations, and deaths due to COVID-19 have been increasing in Quebec since August 2020. In addition to the suffering of those infected and their friends and family, caring for patients and their contacts creates a significant burden for healthcare workers, who are frequently infected, threatening the integrity of our healthcare system. The way the pandemic develops in the coming months will depend on the population’s compliance with the recommendations to minimize contacts, maintain physical distancing, wear a mask, and wash hands. It will also depend on the general measures enacted by the government. Unless there is dramatic improvement in the population’s compliance or there are much stricter measures implemented, we cannot expect a swift decline in the weekly number of new hospitalizations and deaths without vaccination. In the short term, the impact of vaccination will depend on the targeted groups, the vaccination coverage within th…

Comité sur l'immunisation du Québec
20 June 2018

Revision of the Programme d’immunisation contre l’influenza au Québec

The last report issued by the Comité sur l’immunisation du Québec (CIQ) concerning the Programme d’immunisation contre l’influenza du Québec (PIIQ) [Québec’s Influenza Immunization program] was published in 2007. An update became necessary, given the many scientific advances that have occurred in this field.

The primary objective of the PIIQ must be to reduce influenza-associated hospitalizations and deaths.

To attain this objective, the CIQ recommends maintaining a targeted vaccination strategy for individuals at high risk for hospitalization and death and giving priority to achieving vaccine uptake of at least 80% in these groups.

It is recommended to withdraw healthy children aged 6–23 months and healthy adults aged 60–74 years from the list of groups at high risk for influenza-associated hospitalization and death, but to maintain the other groups currently included in the PIIQ.

The CIQ recommends that all healthcare workers receive the va…

Comité sur l'immunisation du Québec
3 April 2018

Advisory report on the Human Papillomavirus (HPV) Vaccination Schedule

A lot of new data on the immunogenicity, efficacy and effectiveness of fewer than three doses of HPV vaccine have become available since the publication of the CIQ report on the 2012 knowledge update. The two-dose schedule has become a standard that is widely accepted around the world. Such schedules are currently in use in more than half (48/82) of the countries offering HPV vaccination programs. The same schedule has been approved and recommended by the World Health Organization (W HO) and the Global Alliance for Vaccines and Immunization (GAVI).

A number of clinical and ecological studies have even come up with some interesting and promising results in terms of the immunogenicity and efficacy of single-dose HPV vaccination. Immunogenicity studies have shown that sero-conversion rates after a single dose of vaccine are often in excess of 95%, although with considerably lower geometric mean titers (GMTs) than those observed after two or three doses. However, antibody titers…

Comité sur l'immunisation du Québec
19 December 2017

Scientific advisory on the optimal schedule for childhood immunization against pneumococcal disease in Québec

The childhood immunization program was implemented in Québec to reduce the burden of pneumococcal disease, with the primary objective of lowering the incidence of invasive pneumococcal disease (IPD). The program began in 2002, targeting children with a high risk of IPD, and in 2004 it became a universal program for all children under age five. A schedule of four doses (3+1) is recommended for high-risk children and three (2+1) for other children. 

The initial 7-valent pneumococcal conjugate vaccine (PCV7) was replaced by the 10-valent vaccine (PCV10) in 2009, and then by the 13-valent vaccine (PCV13) in 2011. Since the program began, immunization coverage rates have been high: over 90% of children receive the recommended number of doses. At the request of the Ministère de la Santé et des Services sociaux du Québec (Ministry of Health and Social Services, or MSSS), the Québec Immunization Committee (CIQ) prepared an scientific advisory regarding the choice of an optimal sched…

Comité sur l'immunisation du Québec
9 September 2014

Initial Dose of a Multicomponent Serogroup B Meningococcal Vaccine in the Saguenay–Lac-Saint-Jean Region, Québec, Canada: An Interim Safety Surveillance Report

To control the spread of the meningococcal serogroup B disease in the Saguenay–Lac-Saint-Jean region which has had a higher incidence rate compared with the rest of the province since 2004, a vaccination campaign was undertaken and targeted individuals 20 years and younger residing in or attending an educational institution in this region. An enhanced surveillance system was implemented to monitor the onset of adverse events following immunization (AEFI) in real time in order to be able to promptly notify the Ministère de la Santé et des Services sociaux (MSSS, Ministry of Health and Social Services) and the Direction de la santé publique (DSP, public health unit) of the Saguenay–Lac-Saint-Jean Health Region (RSS 02) about the occurrence of a safety issue in connection with this new quadrivalent serogroup B Meningococcal vaccine (4CMenB).


This report covers the experiences of individuals residing in region 02 who received their first dos…

31 July 2013

HPV Immunization of Quebec Pre-Adolescents: Two or Three Doses?

In 2007, the Comité sur l’immunisation du Québec (CIQ) recommended an extended schedule exclusively for immunization against the human papilloma virus (HPV) starting in grade 4 (0, 6, 60 months); the committee also stated that the third dose should be administered “if judged necessary.” Since the introduction of the Québec HPV immunization program in 2008, similar programs (two doses administered six months apart and a possible third dose if necessary) have been introduced in Mexico and British Columbia. In 2012, the committee of immunization experts in Switzerland recommended for pre-adolescents a schedule comprising two doses administered six months apart. In recent years, a number of studies have been published on the immunogenicity of HPV vaccines administered according to alternative schedules and other studies are presently underway to document the efficacy of one, two, or three doses administered at different intervals.

The present advisory report, which is based on t…

Comité sur l'immunisation du Québec
13 August 2012

HPV Vaccination in Québec: Knowledge Update and Expert Panel Proposals

The human papillomavirus (HPV) belongs to the Papillomaviridae family, which includes at least 100 genotypes affecting the skin and mucous membranes. Of these, about 40 affect the anogenital area in particular, and approximately 15 are oncogenic. Genotypes 16 and 18 are responsible for 70-76% of cervical cancer cases worldwide. Genotypes 6 and 11 are non-oncogenic but are responsible for most cases of condyloma (anogenital warts [AGW]).

HPV prevalence and incidence data are estimated on the basis of epidemiological studies and are better documented in women than men. HPV prevalence varies widely by geographic region, age, the selected subpopulation and HPV detection method. In women, the overall age-adjusted prevalence of genital infections worldwide is estimated at 11.7%. It peaks in young women aged 20-24 and declines subsequently with age. The risk of acquiring HPV infection is particularly high in the first few years after sexual activity begins. According to some…

Comité sur l'immunisation du Québec