Hello and welcome to Medicine with Dr. Moran. I'm Dr. Keith Moran. Today I want
to talk about another vaccine that just released its phase 3 clinical trial data.
This vaccine is from Novavax. This is a U.S. company based in Maryland
which has produced a protein-based Covid-19 vaccine candidate. Just as a disclaimer I
have no financial or other interests in any of the vaccine products that I talk about on
my channel. This is the first protein vaccine candidate to present their phase three data.
It's a two injection vaccine. It's also the first vaccine to demonstrate significant clinical
efficacy against both the rapidly emerging South African as well as UK strains. Now
this information is coming from the company itself and has not been made fully available nor has it
been peer reviewed but it will be shortly. Now the product is a full length pre-fusion spike protein
which was made with nanoparticle technology which is given along with the saponin-based adjuvant.
The adjuvant stimulates the entry of antigen presenting cells into the injection site and also
enhances antigen presentation in local lymph nodes to try and boost the immune response. Now saponins
are found in plants and in a number of things that we eat such as beans, peas, spinach, tea, quinoa,
peppers, oats, as well as licorice just to name a few. They've been widely used for years.
Now the protein itself is encoded with the genetic sequence of the spike protein
and it's produced in insect cells. It's stable at refrigerator temperatures. It does not cause
Covid-19 nor can it replicate and it's shipped in a liquid formulation that's ready for use.
It stimulates high levels of neutralizing antibodies and has
been used in four different clinical studies in five countries with over 37,000 participants.
Next I want to talk about the UK phase 3 results and then the South Africa results.
first of all the UK phase 3 trial enrolled 15,000 participants between 18 and 84 years of age.
It included 27% over the age of 65. The primary endpoint was based on the first occurrence of PCR
confirmed symptomatic Covid-19 whether it be mild, moderate, or severe with onset at least seven days
after the second vaccination. All participants were negative for SARS Cov-2 at baseline.
Their interim analysis was based on 62 symptomatic cases of Covid19. 56 were seen in the placebo
group versus 6 in the vaccinated group which leads to a vaccine efficacy rate of 89%.
Of the 62 cases 61 were either mild or moderate and there was only one severe case and that was
found in the placebo group. Of the 62 cases 32 were of the UK variant, 24 were of the typical
SARS Cov-2, and six were unknown. Based on the strains the efficacy by strain was calculated
to be 95.6% against the original Covid-19 strain and 85.6% against the UK variant strain. The one
thing that was mentioned about the safety database was that serious, severe, and medically attended
adverse events occurred at very low levels and were described as being balanced between
both the placebo and the vaccine group. Next I want to talk about the South African results.
4,400 patients were enrolled in this study it was the phase two B clinical trial and 60% efficacy
was noted for the prevention of mild, moderate, and severe Covid-19 disease in the 94% of the
study population that was HIV negative. In this population 29 cases were seen in the placebo group
and 15 in the vaccine group. There was only one severe case of Covid-19 and this occurred in the
placebo group. During this time the triple mutant variant which contained three critical mutations
in the receptor binding domain as well as multiple mutations outside the receptor binding domain
was widely circulating in South Africa. In fact 93% of the cases were of this escape variant.
One important thing to note is that about a third of patients enrolled but not included
in the analysis that I just described were in fact positive for antibodies against SARS Cov-2
indicating that they'd been previously infected at baseline. Based on epidemiological data in South
Africa these pre-trial infections were thought to have been caused by the original Covid-19 strain.
While the subsequent infections which occurred during the study were largely of the escape
variant virus. This data is suggestive the previous infection with Covid-19 may
not completely protect you against subsequent infection by the South African escape variant
but vaccination with Novovax definitely provided significant protection. Now Novovax has initiated
development of new vaccine candidates for a booster and or combination vaccine for new
strains and plans to initiate testing these new vaccines in the second quarter of 2021.
One benefit of their vaccine platform is that it uses a very small amount of antigen protein
enabling the rapid creation and large scale production of combination vaccine
candidates that could potentially address multiple circulating strains of Covid-19.
There is another phase 3 trial with this vaccine which is called Prevent 19.
This will finish enrollment in the first half of February of this year. This is being
carried out in the U.S. and Mexico and will enroll 30,000 patients over the age of 18.
Novavax has begun the rolling review process with a number of regulatory agencies worldwide
including Health Canada, UK Medicines, and Health Care Products, U.S. FDA, and European Medicines
agency. They have an agreement in principle with the government of Switzerland to provide
6 million doses of their current offering. They also have a memorandum of understanding with the
Canadian government to produce this vaccine in Canada. Canada has purchased 52 million doses
of the vaccine with an option for an additional 24 million. They expect to supply the vaccine
to Canada as early as the second quarter of 2021 assuming authorization occurs with Health Canada.
The company has an advanced purchase agreement with Australia for 51 million doses
with an option for 10 million more. There's also an advanced purchase agreement with new
Zealand for 10.7 million doses which is their entire citizenry. It's my intent in this and my
other vaccine videos to provide you with the most current information that I've been able to find
and explain it in an easy terms. Thanks a lot for joining me today on Medicine with Dr. Moran.
I'm Dr. Keith Moran. Remember get healthy and stay healthy through this pandemic.