The city of Ontario is being asked to find a vaccine linked to the future development of Covid-19 to determine if the province’s vaccination strategy is more effective in protecting against the virus.
Gerald Evans, an infectious disease specialist at the Kingston Center for Health Sciences, said it was important to know which vaccine was then given to a person infected with COVID-19.
“Is it important for us to add that we have to say that our strategy is good? How does it compare to other countries?” Evans said.
Ontario tests the vaccine status for all Kovid patients, but does not check which vaccine was given by someone who tests positive.
An Ontario government spokesman said the provincial epidemiology team was considering such data breaks but there was no timeline for a decision.
How do you compare Ontario’s strategy?
Canada allowed residents to mix their doses and increase the time between doses compared to what was tested in clinical trials.
Ontario introduced one of three brands: Pfizer-Bioentech, Modernna or AstraSeneca-Oxford, and many received it.
Dr. Earl Brown, a professor of virology at the University of Ottawa, said: “It’s better to be infected with the same vaccine than to be mixed or wait for the second vaccine.”
Brown said it has long been known in immunology that waiting eight to 12 weeks between injections for other diseases boosts immunity. Canada chose to bring the COVID-19 vaccine in line with this practice, largely due to logistics.
Evans said monitoring the time interval between doses for future steps will also help the general public to schedule a third dose.
Immunity weakens over time, and if one vaccine happens faster than another, it may be time for some to shoot a booster, he said.
No vaccine is 100% effective
Evans said immediate chances are not vaccine failures, but those cases become more common as the number of people who receive the vaccine increases. Although they are very good for preventing hospitalization, serious illness and death, no vaccine is one hundred percent successful in preventing infection.
He said that as more data became available, some vaccine and vaccine combinations had been shown to provide stronger protection.
Evans said German and British data indicated that if you received the first dose of the virus vector vaccine AstraZeneca, the MRNA vaccine would be “Pfizer or Moderna” if you “won the lottery”.
“You’d laugh if you got Double Pfizer, Double Modernna. You’d really laugh if you got AstraSeneca and Pfizer, or AstraSeneca & Moderna,” Evans said.
Evans suggests that age may be the main factor influencing whether it is appropriate to vaccinate someone going forward. Children who have the ability to stimulate the immune system are immunocompromised – so when Fizer is available for children 5 to 11 years of age, the dose is only 10 micrograms.
He suggests that Faizer’s micrograms of 30g may be needed by teens and young adults. Larger doses may be needed in the 80s and older because the immune response is low.
“If I’m 30 years old, I’m happy with Moderna. Above 35, Moderna might be the right answer, but Faizer also seems to be doing well,” he said.
According to Brown, the two data show that AstraZeneca is not a double-edged sword.
“AstraZeneca doesn’t look as good as the MRNA vaccine to prevent infection, but it’s still very well kept people out of the hospital, but you’ll start to see some difference there,” he said.