Hello, and welcome to Medicine with Dr. Moran. I'm Dr. Keith Moran. I've been receiving many
questions about all the vaccines which have emergency use authorization. People have asked me
to compare the vaccines and I thought a comparison video would be a good idea. Let's get started.
This slide shows all of the vaccines that have either been peer reviewed, presented in a journal,
or press released data. I have reported on several of these studies in videos on my channel. The
first four vaccines on this slide as of February 20'th 2021 all have peer-reviewed published data.
Pfizer and Moderna were published in the New England Journal of Medicine
and Astrazeneca and Sputnik V were published in the journal Lancet. The bottom two vaccines
Johnson and Johnson and Novavax on the slide have only presented their data in press release format.
They have not published their data. It's highly likely that they are in the process of submitting
it to a peer-reviewed journal where we can all see their data. Currently Pfizer and Moderna
are approved in the United States and Johnson & Johnson is about to be reviewed for emergency
use authorization by the FDA February 26'th. On this next slide the six vaccines are compared.
In the second column the type of vaccine is listed. The Pfizer and Moderna vaccines of
course are messenger RNA vaccines found in lipid nanoparticles. The Astrazeneca, Sputnik V and
Johnson & Johnson vaccines are adenovirus viral vector vaccines using DNA which of course has
to go into the nucleus of your cell in order to translate that DNA into messenger RNA which then
subsequently goes into the cytoplasm of the cell to make the spike protein. The last vaccine is
Novavax which injects a manufactured part of spike protein along with an adjuvant to help it work.
The next column is the number of participants in the trials that were vaccinated with the
actual vaccine. The next column is the number of doses that are used in their phase 3 trials.
Obviously the Johnson & Johnson vaccine has an advantage here with just a single dose whereas all
the other vaccines actually have two doses. Now the responses to these vaccines have been studied
and each one of the vaccines generate a large amount of neutralizing antibodies.
These neutralizing antibodies mean that it will immediately bind and neutralize the Coronavirus
triggering a strong T-cell response. There's also a strong T-cell response to each vaccination.
T-cell responses are very important because we know they modulate the severity of infection
with viruses. T-cells are the major immune defense against viruses.
B-cells as well as B-cell memory and the production of antibodies are also important.
I've mentioned in my previous video Could You be Immune to Covid that there's good data indicating
some degree of cross T-cell immunity from other Coronaviruses. This means that if you've had
other common cold Coronavirus infections in the past that your T-cells will remember this
and will provide you some protection and it's postulated that this will likely lead to more
mild Covid-19 infections. Should you get re-infected after a natural infection or
after vaccination it should be mild if you mounted a good T-cell response. We have seen good memory
T-cell and memory B-cell responses and people who developed the original SARS coronavirus infection
17 years later. This is something that's been studied in the past year. Now the last
column is how successful these are against protecting from a Covid-19 hospitalization.
You'll note that all of them are essentially 100% successful. There was one patient in the Moderna
trial that got hospitalized after the first dose. On the next slide are the results for each vaccine
against mild disease as well as severe disease. While I've presented the numbers from each one
of the vaccines here you have to remember that these vaccines have never been compared
head to head in order to say whether one vaccine is actually better than another
in a specific population. In terms of protection against severe disease they all do an excellent
job as you can see based on the data essentially 100%. When it comes to mild disease a number of
the vaccines have been tested in South Africa as well as the UK and Brazil where variants have been
found so it's not particularly surprising that the percentages are less in those particular
populations. In terms of preventing mild disease in fact as you may know the South African trial
with Astrazeneca was halted as the results for preventing mild disease with the South African
variant were felt to be sub-optimal even though it did a great job at preventing severe disease.
When you look at this chart the vaccines are doing a great job at preventing hospitalization
and severe disease so that the people who do acquire the Coronavirus will either be completely
asymptomatic in the majority of people or have a very mild illness in the remaining people.
Remember a mild illness is quite manageable at home just like the common cold that we've all had.
Thus it would prevent large numbers of deaths and a strain on health care systems of the world.
Thank you for watching me today on Medicine with Dr. Moran.
I'm Dr. Keith Moran. Remember get healthy and stay healthy through this pandemic.