For a year and a half the world has been paralyzed by a new coronavirus, but in a second pandemic fall, some experts warn of the return of a virus that we know well: influenza.
Last winter, public measures designed to slow the spread of COVID had the unintended consequence of making the flu almost non-existent. But with the easing of restrictions and cooler weather suggesting a return to the interior, some are warning of the possibility of a recovery season, in which the flu virus takes hold thanks to the lack of natural immunity generated by the year. last.
The director of the Centers for Disease Control warned that the US could be a risk of a severe season, while the Public Health Agency of Canada said in a statement that it is preparing for a possible resurgence, and the burden that this could represent for the healthcare system that is already struggling with COVID.
“Last year, due to closures, public health, distancing, masking, hand washing, etc., there was actually very little influenza,” said Dr. Anna Banerji, infectious disease specialist at the University. from Toronto. “When you don’t have the flu for a while, usually when it comes back, it tends to be more serious.
“I think it will probably be a very deadly flu year.”
While an increase in the flu would send patients to intensive care units that are already overwhelmed and already overwhelmed by COVID patients, experts note that the solution here is a familiar one.
Shipments of the flu vaccine have already begun to be distributed across the country, and Ontario, for its part, says it is preparing for its largest flu vaccination campaign in provincial history. Unlike last year, the vaccines will be available starting in mid-October for high-risk people and will open to the general population in November.
One of the reasons the flu is so cunning is how quickly it mutates – in COVID parlance, there are thousands of variants circulating at any given time. People develop immunity to various strains when they are infected with the flu and when they get the flu vaccine, which is designed to protect themselves from three or four strains.
You get a new vaccine every year not because the old one goes away, but because the flu has generally evolved.
As Scot Simpson, a professor of pharmacy at the University of Alberta, says: “The way the influenza virus works is that it changes layers. Like instead of wearing a blue down-filled jacket one year, it’ll be a green raincoat. “
Like every year, these vaccines have been in development since February, when the World Health Organization made its predictions about which strains would be dominant in the Northern Hemisphere this year, prompting several vaccine manufacturers to begin preparing the vaccines. of this year.
Various companies are starting to make flu vaccines, sometimes using slightly different techniques or doses, but targeting the same viruses established by the WHO.
“Influenza is probably one of the most complex and dynamic viruses facing public health,” says Bruce Seet, director of medical affairs for Sanofi Pasteur, one of the companies that makes large quantities of influenza vaccines for the Canadian market. .
It’s a constant arms race, he says. Not only must scientists guess which strains will be dominant, but there may be different versions in different locations, or even some genetic change within the season.
It’s just a big company too – much of Sanofi starts with thousands of fertilized chicken eggs, which are used to prepare large amounts of viruses, which are killed, sterilized and converted into individual doses that will hopefully teach your body to fight. the flu.
Seet says it’s unclear if last year’s flu off season will affect this year’s vaccine. For one thing, less flu last year means less data from which to build a new vaccine, he says. But less flu could have meant the extinction of entire families of flu viruses.
As always, the flu’s biggest question mark is what Seet calls its superpower: it mutates and it’s fast.
“It’s a moving target,” says Seet. “But at the end of the day, it’s like shooting 1,000 different targets.”
Experts say vaccines will be particularly important this year, given the concern of some is the lack of natural immunity.
A pre-printed article, yet to be reviewed by other scientists, published by a group of US researchers in August predicts a “major compensatory flu season” this year.
As the study says, “During the low flu season in 2020-21, the population missed the opportunity to establish or boost their immunity for the future flu season.”
In a launch, Dr. Mark Roberts, director of the Public Health Dynamics Laboratory at the University of Pittsburgh, noted that the lifting of containment measures for COVID-19 was resulting in a “fierce resurgence of other respiratory viruses, which did not bodes well for the coming flu. ” season.”
The risk increases as you go. If the flu were to stay low for several seasons, then the number of susceptible people would continue to rise, which could lead to a large outbreak.
But the model also points to the importance of getting vaccinated. If the absorption or efficacy of the vaccine improved by 50 percent (or if each improved by only 25 percent), hospitalizations would remain the same.
The stakes here are clear: With intensive care units across the country currently besieged by COVID, a resurgence of other diseases could sink them.
The authors acknowledge the study’s own limitations, in particular that it is difficult to say exactly when it will decrease, whether natural or induced by the vaccine, or how much the virus itself will change.
Simpson says it’s too early to tell what flu season will look like, though he’s optimistic that masking and social distancing will have the same effect as last year, when flu season was all but eliminated.
While there is less information to date from last year, he notes that there was still enough information for the WHO to recommend a new cocktail of virus strains: This year’s flu vaccine includes a strain that has been around since 2013 and a new one that was identified last year.
Simpson says there is some debate about how prepared you are in general if you get vaccinated each year, and some research suggests that having a “constellation of antibodies” from different flu vaccines in your system could give your body the opportunity to fight to recognize new strains.
But according to Health Canada, it is estimated that the virus affects between 5 and 10 percent of adults each year worldwide and between 20 and 30 percent of children. Together, the flu and pneumonia are among the top 10 causes of death.
Over the past 10 years, an average of 30,000 laboratory confirmed flu cases, appropriately titled FluWatch, have been reported to the national surveillance program.
Pam Tomasevic begins her search in early October each year: she began calling doctors’ offices and pharmacies in an attempt to find a flu vaccine.
Entering a second pandemic winter, Tomasevic, an elderly person living in Mississauga, wanted to make sure he was protected against both viruses, but says not much information is available yet.
“It’s frustrating when each person has to figure this out for themselves, instead of having standard information available to everyone,” he said.
Especially now that things are a bit more open, ”he says. “I want to be protected on all fronts: COVID and flu.”
Experts are hopeful that after a year of hearing about vaccinations, more people will hear the call to get vaccinated. Simpson sees hope in the fact that people are more aware of vaccine technology than ever.
“I think it’s a good thing because people are becoming more aware that they are susceptible in the first place or if they develop infections, these infections can be quite serious.”
Seet notes that while older people tend to get more flu shots, the vaccination rate among adults is typically only 20 to 30 percent. The worst thing we can do, he says, is underestimate the flu. Often characterized as sneezing, it has great potential for global spread.
“If there are still many people who are not vaccinated against influenza, it means that there is more chance of transmission and variation,” he says.
“Having a large unvaccinated population creates the conditions for viruses to do what they do. Be opportunistic. “
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