The vaccine that will specifically target the Omicron variant will likely not be ready in time to stem the current wave of COVID-19, according to Health Canada’s senior medical adviser.
According to Dr. Supriya Sharma, what is really needed are vaccines that can possibly stop more than one variant at a time, including those to come.
Omicron became the dominant variant in Canada in just over two weeks, and the Public Health Agency of Canada said Friday that it will now be responsible for more than 90% of all COVID-19 cases.
Studies have suggested that two doses of the existing mRNA vaccines from Pfizer-BioNTech and Moderna are not as effective in preventing infection with the Omicron variant.
Numerous studies, however, suggest that vaccines are excellent for keeping symptoms mild, preventing hospitalizations, as well as shortening the stay and lowering the standard of care for those admitted to hospital. Fewer patients vaccinated against the Omicron variant, for example, need a ventilator.
Both Pfizer and Moderna are working on new versions of their vaccines that specifically target the Omicron variant.
Moderna hopes to have its product in trials early this year. Pfizer said it could have 100 million doses of its product as early as March, and Canada has contracts with both companies for recalls that would also include variant vaccines.
Dr. Sharma said the fast-track review process for vaccine variants is “probably not” fast enough.
“By then, from what we know of the Omicron wave, it could well be over,” she says. And then the question is always whether there is another variant looming.
The solution, she says, likely lies in vaccines that can target more than one variant at a time.
The World Health Organization’s (WHO) Technical Advisory Group on Vaccine Composition made the same statement on January 11, noting that Omicron is the fifth variant of concern in two years and “probably won’t be the last.” .
Booster injections that boost antibody development have become the immediate response to the Omicron variant for many countries, including Canada.
Dr. Srinivas Murthy, a pediatrician in British Columbia and co-chair of the WHO Vaccine Composition Technical Advisory Group on COVID-19, says booster doses are not a viable long-term option.
“If you’re trying to get out of a pandemic, you inevitably shoot yourself in the foot, in the sense that there will be a new variant that will emerge that will cause problems, he says. He will escape your vaccines, and then you will have to face difficulties. »
“Omicron is not entirely immune to existing vaccines, but a future variant may do so,” adds Dr. Murthy. A lot of the problem is that the original vaccines train the body’s immune system to recognize what’s called the spike protein, which is on the surface of a virus, and that spike protein is changing significantly. »
The mutated spike protein is like a kind of disguise that makes it harder for the immune system to recognize the virus and mount a defense to kill it.
Omicron has more than 50 mutations, including at least 36 on the spike protein.
Multivalent vaccines that use the spike protein of more than one variant or that target the genetic components of a virus rather than the spike protein are perhaps the ones that could offer protection against both this pandemic and the next new coronavirus that will appear.
“It’s a ‘pan-coronavirus’ vaccine, which allows for broad neutralizing responses and doesn’t need to be updated every season and so on,” says Dr Murthy. It has been the holy grail of influenza vaccinology for several decades. We haven’t gotten there yet, because the flu is a little tricky, but we think it’s doable for the coronavirus, specifically. »
The US military has a version that is entering phase 2 trials that can bind several advanced proteins. A vaccine containing the specific proteins of the five COVID-19 variants would likely be more effective, even against future variants, because they all share some of the same mutations and what one might miss another might grab.
Moderna is working on multivalent vaccine trials using spike protein combinations of the original virus and one of the variants, or two of the variants together. It is not yet known when they will be ready for use.
Dr. Sharma says that while the vaccines don’t work as well against the variants as they do against the original virus, to her “they’re still miraculous.”
“Having a vaccine that was developed so quickly, that still has, across multiple variants […] with boosters, up to 70, 80 percent effective against serious illnesses, ailments, hospitalizations and deaths, she points out. This is miraculous for a new vaccine against a new virus”.