Dr. Gordon Dow knows the seriousness of COVID-19 as an infectious disease specialist.
He’ll tell anyone to defeat the virus, people have to have a suit of armour and a shield.
He works with Horizon Health Network and gave a presentation on how vaccines help prevent hospitalizations and death, but also that it provides extensive immunity against the COVID-19 virus.
“The pharmaceutical industry have been working day and night to develop vaccines and to date more than 20 vaccines have been given emergency use authorization globally and well over a 100 vaccines are undergoing research and testing right now,” he said in the presentation on Friday.
“This has resulted in the fact we now have three billion people vaccinated world-wide.
In Canada, there are four authorized vaccines with two being “workhorse vaccines,” Dow said.
The straight facts
Those are Comirnaty (Pfizer), SpikeVax (Moderna), Astra Zeneca, and Johnson and Johnson. The latter two have not seen much use in Canada or Atlantic Canada, Dow said.
Dow reported that 51 studies were done for the Comirnaty vaccine and 14 for the SpikeVax. Both fell within the 90 to 100 per cent range at preventing death.
Comirnaty was 85 to 98 per cent effective against severe infection.
Spikevax was 90 to 96 per cent effective against severe infection.
Comirnaty and Spikevax were 80 to 95 per cent and 87 to 100 per cent effective against symptomatic infection, respectively.
“Both these vaccines are very effective,” he said. “They aren’t bulletproof, but they are effective.”
Spikevax and Comirnaty were 92 per cent and 65 to 95 per cent effective against asymptomatic infection, respectively.
Both have high rates of preventing just about any infection which includes all of the situations above, Dow said in his presentation.
However, there are limitations and reduced efficacy worth noting, he added.
Comirnaty shows reduced efficacy in people who are immunocompromised. Both show reduced efficacy for the Beta and Delta variants.
Life cycle of viruses
Dow said the virus replication cycle is eight hours.
The virus can make up to 1000 mutations per day during peak infection.
“Most of the mutations do not help the virus but a few do make it more fit to infection people, better at escaping vaccines,” he said. “We should expect variants going forward.”
For comparison, Dow spoke about the typical cell replication cycle. The virus replicates every eight hour while in human’s typical replication cycle, it’s 25 years.
“It takes us 25 years to do what this virus does in eight,” he said. “Human adaptation, genetic adaptation occurs slowly because the generation time is 25 years. With these things, they replicate every eight hours.”
Long-term effectiveness
Dow also explain how the vaccine holds up over time.
After one month post-vaccination, it holds up against infection of non-Delta at 97 per cent. For Delta, it holds up at 93 per cent.
After four months, it holds up against infection of non-Delta at 67 per cent and Delta at 53 per cent.
After six months, it holds up against hospitalizations for non-Delta at 95 per cent and for Delta at 93 per cent.
He said because it does wain at about the six month mark, governments and Public Health are moving to give boosters and third doses for those most vulnerable.
“You can see they are very robust,” he said. “These vaccines work exceptionally well at preventing hospitalizations and death.”
Vaccinations, Dow said, have saved 3 million lives since being approved for emergency use, with 140,000 between just January and May 2021 in the U.S.
Moving forward against the virus
“Vaccines provide their greatest benefit at an individual level and they do this by preventing hospitalization and death,” he said.
He said public health measures work on a population level.
Dow said it’s simple if people think about it this way:
“Vaccination is your suit of amour and that protects you from hospitalization and death. Public Health measures is the shield that protects our population from transmission of COVID to one another.”
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