The information in this slide deck was presented at the Asha-Deep Project webinar on Thursday 18th February 2021

1. COVID-19 variants and vaccines
Varsha Khodiyar, PhD

2. What is a virus?

3. Key virus facts
Source:https://www.open.edu/openlearn/science-maths-technology/biology/what-virus
● Genetic information (DNA or
RNA) surrounded by protein
● Different shapes and sizes,
typically 20–300 nm
● Cannot reproduce
independently, needs a host cell
● Can survive for only short
periods outside a host cell

4. The SARS-CoV-2 virus which causes the disease COVID-19
Image source: https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=300334&org=NSF

5. Our cells also have RNA
Image source:
https://giphy.com/gifs/biology-primer-mRI1hW0ZBVUly
Image source:
https://www.ajconsultingcompany.com/cells_and_dna.html

6. What does the virus RNA do in our cells?
Image adapted from: https://courses.lumenlearning.com/boundless-biology/chapter/virus-infections-and-hosts/
SARS-CoV-2 attaches to
human cell using the
spike protein
SARS-CoV-2 virus
Human cell

7. ● DNA and RNA are types of
genetic material
● RNA is a naturally
occurring part of our cells

8. How do new virus
strains evolve?

9. Changes to DNA or RNA can alter protein sequence
Image from: https://medlineplus.gov/genetics/understanding/mutationsanddisorders/possiblemutations/

10. Genetic material is routinely damaged,but usually repaired
Image adapted from: https://www.env.go.jp/en/chemi/rhm/basic-info/1st/03-02-03.html
Change caused by
chance or by
environment
(e.g. smoking)

11. RNA viruses do not have the same type of repair mechanism
and so are more likely to accumulate changes (mutations)
Image source: Proc Natl Acad Sci U S A 2010 doi: 10.1073/pnas.0906193106

12. Most changes will make the protein worse at doing its
job...
Image from: https://medlineplus.gov/genetics/understanding/mutationsanddisorders/possiblemutations/
...but by chance
some changes
may make the
protein better at
doing its job

13. Lots of changes results in new virus variants
Source: https://www.bbc.co.uk/news/health-55659820

14. ● Changes to the genetic code
(mutations) happen all the time
● Most changes will make a protein
less effective
● Multiple changes can result in the
evolution of a new virus variant

15. What do we know
about the new
SARS-CoV-2 strains?

16. Research into SARS-CoV-2 and COVID-19 is ongoing

17. What we know so far
Sources: https://www.cdc.gov/coronavirus/2019-ncov/transmission/variant.html ; https://www.bbc.co.uk/news/health-55659820
Identified variants are more transmissible,
i.e. easier to catch
Masks & social distancing work against these new variants
All variants recognized by existing vaccines

18. How do the coronavirus vaccines work?
Sources: https://wellcome.org/news/what-different-types-covid-19-vaccine-are-there
https://www.nhs.uk/conditions/coronavirus-covid-19/coronavirus-vaccination/coronavirus-vaccine/
Currently approved in the UK
Viral vector vaccine: Oxford-AstraZeneca
RNA vaccines: Pfizer-BioNTech, Moderna
Use the cell’s own protein making machinery to
make the virus protein
The viral protein triggers an immune response
The vaccines can be modified to recognise the new
strains

19. More about vaccines
Source: https://wellcome.org/news/what-different-types-covid-19-vaccine-are-there

20. Source: https://www.immunology.org/news/whats-in-vaccine

21. What do we mean by‘vaccine efficacy’?
Hypothetical efficacy of 80%
80 people in clinical trial protected against disease
20 people in clinical trial did not gain protection
against disease
Image adapted from: https://www.bmj.com/content/369/bmj.m1808
Reported efficacy against
original covid-19 strain
Oxford-AstraZeneca - 84%
Pfizer-BioNTech - 95%
Moderna - 92%
Source: https://www.who.int/

22. Poll -What is the effectiveness of the yearly flu vaccine?
0-20%
20-40%
40-60%
60-80%
Over 80% Flu vaccine image from www.shutterstock.com

23. 40-60%
Effectiveness of the yearly influenza vaccines
(Reduction in risk of having to go to the doctor with flu)
Source: https://www.cdc.gov/flu/vaccines-work/effectiveness-studies.htm

24. SARS-CoV-2 will mutate
every time it replicates
We can reduce the chance for
new strains to evolve by
reducing the opportunities for
the virus to reproduce

25. COVID-19 is likely to become endemic
Source: https://www.nature.com/articles/d41586-021-00396-2

26. Finding out more
Image source:
https://mrbarlow.wordpress.com/2012/11/24/take-breaks-to-learn-more/

27. Use reputable news sources for latest information
Information sources I find useful:
BBC news website
BBC, ITV and Channel 4 TV news
programmes (radio & TV)
USA CDC website
(https://www.cdc.gov/coronavirus/2019-ncov/variants/index.html)
Nature news features
(https://www.nature.com/nature/articles?type=news-feature)
How can you tell if the information
is accurate?
Check multiple
sources

28. Debunking coronavirus myths -www.covidfaq.co

29. What is the difference between fact and opinion?
A fact is true, whether
or not you believe it
Can be proved to be
correct with evidence.
An opinion is what
someone thinks or
believes.
Cannot be proved to be
correct or incorrect.
Source: https://www.bbc.co.uk/teach/skillswise/fact-or-opinion/z4r7cqt

30. Check that your information
sources are reputable and
worthy of your trust

31. “Knowledge is power”
Sir Francis Bacon (1597)

32. @varsha_khodiyar
Varsha Khodiyar
The information in this slide deck was presented at
the Asha-Deep Project webinar
Thursday 18th February 2021
Asha-Deep Project email: ashadeepc19@gmail.com
Slide deck created by
Varsha Khodiyar
Slide deck licensed as CC-BY
https://creativecommons.org/licenses/by/4.0/