Continue to vaccinate the general population against COVID or not? At the beginning of 2023, Quebec has not yet made a decision on the follow-up to the bivalent vaccine, but all indications are that the Quebec Committee on Immunization of Quebec (CIQ) will not advocate comprehensive vaccination, but rather targeted measures to prioritize vulnerable individuals who are still never infected.
As cases of COVID-19 soar in the United States, spurred by the arrival of the new subvariant XBB.1.5 — even more contagious than its predecessors — many people are wondering if the immunity conferred by a vaccine (monovalent or bivalent) will , fall or infection will be enough to protect them this winter.
The CIQ, which reports to the National Institute of Public Health of Quebec (INSPQ), has already sent its opinion to the government, which will soon decide what action to take and what recommendations to make to Quebecers.
But as 2023 begins, several health authorities around the world still have doubts about the stage that will follow the bivalent vaccine granted three or four months ago. “What are we doing for 2023? Many ask themselves this question. Nobody has decided yet. One thing is for sure, those who received the bivalent vaccine in Quebec in October are immune for a long time to come,” says Dr. Gaston De Serres, Member of the CIQ and Medical Advisor to the INSPQ.
So do we need a new vaccine dose to face the winter? It certainly seems that the current answer is no… for the general population.
The uninfected under the radar
Without revealing what the committee will recommend, Dr. De Serres said the CIQ’s scientific opinion will be based on the same data that formed the basis of last November’s opinion.
At the time, the expert committee did not recommend giving the bivalent vaccine to the healthy population, but only to people who had never been infected and belonged to at-risk groups — residents of CHSLDs and RPAs, those over 60, and those who were particularly immunocompromised or chronically ill. However, Quebec has continued to urge people who have been vaccinated for longer than six months to “stay informed”. “However, the CIQ has not recommended a new dose for the youngest or already infected healthy people. The government has nevertheless decided to make the vaccine available to everyone,” he says.
Current data shows that healthy people with hybrid immunity (vaccination and infection) do not need an additional dose
However, from a scientific point of view, data collected in Quebec among the over 60s since the arrival of Omicron shows that hybrid immunity (conferred by both an infection and a monovalent vaccine) still offers very good protection against hospitalizations in the following six to eight months (more than 90%), regardless of the number of doses received (two, three, four or five doses).
“The effectiveness of the vaccines increased between doses because the vaccines were administered over a short period of time. But over time, the protection decreases, and our data show that effectiveness is ultimately the same after six months, regardless of the number of doses administered,” explains Dr. De Serres.
The expert adds that it is completely different for people who have never been infected, who benefit from a repeat vaccination if they belong to a risk group. In this population, vaccine effectiveness in preventing severe COVID increases from 32% after one dose to 74% after five doses. Important dates, because according to Dr. De Serres, up to 50% of people over 60 have never been infected, while 75% of young people have been.
“Current data shows that healthy people with hybrid immunity (vaccination and infection) do not need an additional dose,” he says.
XBB.1.5 and China
However, some observers believe the XBB.1.5 variant, which is at the origin of the current surge in hospital admissions in the United States, argues for a vaccine resurgence. Health Minister Christian Dubé described the situation south of the border as “worrying” on Thursday and said he was monitoring developments closely. Others add that the virulence of the epidemic in China, which favors the emergence of variants capable of thwarting current immunity, also speaks in favor of a recall.
“If it turns out that a new variant can bypass the vaccine … we will not be able to bring the vaccine back to the market,” responds Dr. De Serres. But if the same subvariants are affected, increasing vaccine coverage for vulnerable people who have never been infected would make a lot more sense than offering another dose to everyone. There’s no point in chasing after people who won’t change anything with the vaccine. »
We’ll have to await the CIQ’s statement to know the exact position he’ll take. But in the end, Quebec will decide whether or not to ask citizens to come back.
An earlier version of the text, which said the CIQ was due to give the government its advice on vaccination against COVID shortly, has been amended. In fact, the CIQ has already sent it to Quebec.