The latest mutation involving the Omicron variant has caused a rapid increase in cases in Ontario and renewed concerns about a possible revival of public health measures.
Here’s what you need to know about BA.5 and Ontario’s latest wave:
So what exactly is the BA.5 sub-variant?
The subvariable was first identified by scientists in South Africa in January and has been officially tracked by the World Health Organization since April.  It has already led to a resurgence of virus activity in several countries, including Portugal, the United Kingdom and the United States.  The good news is that it is not believed to cause more severe disease than previous strains of Omicron, but it could be more virulent.  In Ontario, the percentage of samples identified as BA.5 after whole-genome sequencing has risen from 14.8 per cent this time last month to about 66 per cent as of July 6, and is now being blamed for the first summer wave of Ontario since the start of the pandemic.
“I think the fact that it’s quickly becoming mainstream is a way of showing how infectious it is,” Dr. Karen Bourne, who is the assistant scientific director of the Ontario Science Advisory Panel, told CP24.com this week.  “We’re learning more about BA.5 every day, there’s just a huge amount of studies going on, but early studies show that it replicates faster compared to previous strains and replicates faster in the body as well.  , making it very effective and much more contagious.”
What does it do on the broadcast?
Most experts agree that Ontario is now in a seventh wave of the pandemic driven by the BA.5 subvariant.  The scientific panel said the wave likely started on June 17, although there is no real consensus on when it might peak.  The number of people hospitalized with COVID-19 in the past month rose by about 52 percent to 712, according to the latest figures released by the Ministry of Health on July 7.  However, the burden on the health system is nowhere near what it was during the initial Omicron wave in January, when more than 4,000 patients were hospitalized with COVID-19.  Most experts agree that Ontario is unlikely to see thousands of COVID-positive people in hospitals during this wave, but there are concerns about how well-equipped the health care system is to respond to even a modest increase in volume. the patients.
“The challenge is that this surge comes at a time when the health care system remains very fragile, very overdue, and its summer vacation, so nurses, doctors and other health workers are all taking time off,” Bourne told CP24 .com.  “So, you know, the system is potentially at a time where it doesn’t have the capacity for, you know, a huge surge of increased demand.”
Do existing vaccines still work against BA.5?
Yes and no.  Scientists have identified several mutations in BA.5 that could help it evade the body’s immune response, either from vaccination or previous infection.  That could account for some of the increased transmissibility associated with the virus, experts say.  There was also a study published this week that found that vaccination or recovery from a COVID-19 infection before 2022 now provides little or no protection against re-infection in the Omicron era.  Vaccination, however, is still believed to be highly effective against hospitalization and death, even in the era of BA.5.
“Basically what it does is it just takes away some of the protective immunity that we might have acquired from vaccination or from recovering from infection, so that people are susceptible to infection or re-infection, even those who have been vaccinated or infected the past,” infectious disease expert Dr.  Isaac Bogoch.  “That doesn’t mean everyone will be infected.  That doesn’t mean we’re back to square one by any means.  It just means that one component of the immune system, the antibody response, doesn’t protect us as well as we once did in terms of infection.”
What about rapid tests?
The Chief Medical Officer of Health Dr.  Kieran Moore said this week that later Omicron variants, including BA.5, have affected the sensitivity of a standard rapid antigen test, reducing sensitivity to 50 to 60 percent.  Moore said you can assume you have COVID-19 if you’re positive, but a negative test isn’t enough to conclude you’re free of COVID-19.
If BA.5 is so different why isn’t it classified as a variant of concern?
There have now been five sub-variants in the Omicron era, and despite notable genetic mutations that make each one slightly different, Bogoch said they all seem to “fall under the same umbrella”.  He said he’s heard some people “whining that BA.5 is a long way from BA.1 and BA.2,” but he doesn’t think how the virus is classified makes a huge difference.
“There are some subtleties associated with the BA.5 that make it different from others.  But really the public health message remains the same.  Nothing has changed in terms of how best to protect yourself and those around you from the virus,” he said.
Who is most at risk of BA.5 infection?
Bogoch said other countries’ experience shows it’s the same people who are at risk throughout the pandemic, especially older Ontarians and those with underlying health conditions.  However, he said there is also an increased risk factor for people who are not fully up-to-date on their vaccinations.  That could, of course, be a problem in Toronto where only about 54 percent of eligible residents have received a third dose.
“I think there are some misconceptions that members of the public have where it’s like I have COVID, I had COVID in 2020 and I’m not going to get it again.  This is simply not true,” Bogoch told CP24.com.
Could this wave end up reviving some public health restrictions?
Dr Moore told reporters this week that he was “not considering proposing to the government any other public health measures” at this time.  He said if BA.5 results in an increase in transmission to the point where the province’s health care system is threatened, he would act, but he does not expect to.  Bogoch, meanwhile, told CP24.com that the threat posed by BA.5 can best be addressed through “honest and effective” communication with the public rather than legislation.
“We’re talking about communication to help develop positive human behavior.  But that doesn’t mean a press conference at 3 o’clock in the afternoon saying “Hey everyone, this is a wave, put your mask on.”  You actually have to have a dedicated communications strategy and build trust in the communities,” he said.  “We talk about it like it’s just virology, public health and medicine, but it’s not.  If you really want to create safer communities and better protect Canadians, that means you have to use the expertise of social scientists and have meaningful community outreach and meaningful communication strategies, because a lot of that is making sure that people take the steps that they need. they must do to protect themselves and those around them.”
Will a vaccine specific to BA.5 be approved?
Several manufacturers are racing to develop new vaccines that target the Omicron variant more specifically.  Moderna is believed to be finalizing regulatory submissions for its bivalent vaccine, which combines part of the original mRNA formula with a new updated version designed to better neutralize Omicron.  Clinical trial data released last month revealed that the vaccine is more effective against BA.5 than the currently approved booster vaccine.  However, the data showed a reduced immune response against BA.5 compared to BA.1.  Speaking to reporters this week, Moore said Ontario expects to have access to updated vaccines in the fall, but is still seeking “clarity” on “what the components of the fall vaccine will be.”
“If it’s going to be BA.4 or BA.5 (specifically) I expect they’ll have to ramp up production and it might be delayed a bit, so maybe November or December,” he said.