COVID-19 in 2021: New challenges and renewed optimism - Dr. Bonnie Henry receiving first dose of the Pfizer-BioNTech vaccine Dec. 22, 2020.
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
COVID-19 in 2021: New challenges and renewed
optimism
Dr. Bonnie Henry receiving first dose of the Pfizer- January 12, 2021
BioNTech vaccine Dec. 22, 2020. Stephen McCarthy, PhD
Presentation outline:
1. COVID-19 epidemiology
2. BC COVID-19 Immunization progress
3. Emerging COVID-19 strains
New -80●C freezers arriving at the
VCH MHO office, Vancouver J
1. COVID-19 Cases: Canada
COVID-19 Cases: Provinces
COVID-19 Cases: Health Authority
BC Restrictions extended until Feb 5 th • Minimal changes to what already existed since last order in December, none that affect medical students. • New federal proof of negative COVID-19 test 72hrs before boarding flight to Canada (Jan 7, 2021).
Outbreaks in LTC facilities continue: • By the end of January, all health care workers and residents who want a vaccine will receive their first dose of vaccine against SARS-CoV-2.
2. BC COVID-19 Immunization progress:
• As of January 11th,
351,763 Canadians
have received at least
one dose.
• 0.925% of the
Canadian population
has received at least
one vaccine dose.
• 84.13% of BC’s doses
have been
administered.
2. BC COVID-19 Immunization progress:
• Vaccinating approximately
32,000 Canadians a day.
• Jan/Feb in BC: Long term
care workers/residents,
assisted living residents, HCW
in direct care of COVID-19
patients, remote first nations
communities, precariously
housed in Vancouver’s
downtown East Side.
• Feb/Mar in BC: Expect
medical students to be
vaccinate with other HCW.
• AstraZeneca adenovirus
vaccine close to approval.
mRNA vaccines: • After deltoid injection, dendritic cells take up the lipid particles containing mRNA sequence encoding spike protein epitope. • Body will produce cell-mediated and antibody-mediated immunity to the spike protein synthesized for approximately 10-14 days. • Both Pfizer-BioNTech and Moderna vaccines require two doses. This has led to ethical discussions about maximizing distribution of dose 1 with limited supply.
New clinical data:
• Reviewed by the WHO SAGE committee,
Health Canada, BC CDC, BC Immunization
Committee and the BC Vaccine Evaluation
Centre.
Moderna vaccine: Pfizer-BioNTech vaccine:
14 days 92.1% 14 days 92.6%
Dose 1 efficacy Dose 1 efficacy
21 days 19 days
Similar Similar
Dose 1 Dose 2 efficacy Dose 1 Dose 2 efficacy
42 days 95.2% 42 days 94.8%
Dose 1 Dose 2 Dose 1 Dose 2Broader Community vaccination:
• Greater quantities of Moderna, Pfizer-BioNTech vaccines expected in March.
• Minister Adrian Dix believes we will reach 10% of the
provincial population by March 31st.
• Assuming the Rt of the virus does not change, Dr. Réka Gustafson
is optimistic that community immunity of ~ 70% of the population
can be reached by early Summer or Fall.3: Emerging COVID-19 Strains: B.1.1.7 in the UK
• Other names: VOC 202012/01, 20B/501.V1
• First detected in South-East England on
September 20 2020, arrived in Canada
December 26, 2020.
• Key mutations:
• N501Y: one of 6 key residues in the
ACE2 receptor binding domain (RBD), which
increases binding affinity.
• 69-70del: a commonly seen deletion
thought to allow for immune evasion.
• The B117 strain may be more transmissible by as much as 74% higher than the original strain
detected in Wuhan, potentially increasing the Ro of the virus by 0.4.
• Good news: preliminary data suggests antibodies from those vaccinated with the Pfizer-BioNTech
vaccine can neutralize viruses with the N501Y mutation ex vivo.3: How big is an increase in Rt by 0.4?
Strains B.1.1.7 in the UK
• It took 3 months for
the B.1.1.7 to
become the most
prevalent strain in
the UK.
• Modeling suggests it
will become the
dominant strain in
France in February.
• In the USA, by
March.COVID-19 strain 501.Y2 in South Africa:
• Other names: 20C/591Y.V2, B.1.351 lineage
• First detected in South Africa in October 2020, likely began in Eastern Cape
province August 2020. It arrived in Alberta January 9, 2021.
• Key mutations:
• N501Y
• K417N
• E484K: in the RBD associated with 90% reduction in vitro binding of
polyclonal serum antibodies from COVID-19 + patients.
• Virus has increased transmissibility, may be more virulent (Ct
reduced by 2 by PCR, but more research needed), may infect young
adults more often. Not more severe infection.How do we prepare for these new strains? • Continue our provincial vaccine campaign. May need higher % community immunity. • Reduce international travel. • Increase genomic sequencing of COVID-19 positive samples. • Continue our non-pharmacological interventions and enhanced hygiene practices. • Both the Pfizer-BioNTech and Moderna vaccines are purportedly able to update the mRNA sequence in 6 weeks time, if needed. • Vaccine role out in South Africa will be important to follow and watch.
You can also read
