An overview of where we are in covid-19 vaccine development, including an introduction to immunology and types of vaccines.

1. Covid-19 Pandemic:
Vaccine Development
Rachel Mackelprang, Ph.D.
California State University Northridge
Department of Biology
rachel.mackelprang@csun.edu
@rmackelprang

2. How we develop immunity
Virus is ingested by
specialized immune
system cells called
‘antigen presenting
cells’
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

3. How we develop immunity
Virus is ingested by
specialized immune
system cells called
‘antigen presenting
cells’
T-helper cell
Antigen presenting cells
display pieces of the virus to
activate T-helper cells
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

4. How we develop immunity
Virus is ingested by
specialized immune
system cells called
‘antigen presenting
cells’
T-helper cell
Antigen presenting cells
display pieces of the virus to
activate T-helper cells
T-cells activate other
immune responses
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

5. How we develop immunity
Virus is ingested by
specialized immune
system cells called
‘antigen presenting
cells’
T-helper cell
Antigen presenting cells
display pieces of the virus to
activate T-helper cells
Cytotoxic
T-cell
Cytotoxic T-cells identify
and destroy virus-
infected cells
T-cells activate other
immune responses
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

6. How we develop immunity
Virus is ingested by
specialized immune
system cells called
‘antigen presenting
cells’
T-helper cell
Antigen presenting cells
display pieces of the virus to
activate T-helper cells
Cytotoxic
T-cell
Cytotoxic T-cells identify
and destroy virus-
infected cells
B-cell
B-cells make antibodies that block the virus from
infecting more cells and mark it for destruction
T-cells activate other
immune responses
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

7. How we develop immunity
Virus is ingested by
specialized immune
system cells called
‘antigen presenting
cells’
T-helper cell
Antigen presenting cells
display pieces of the virus to
activate T-helper cells
Cytotoxic
T-cell
Cytotoxic T-cells identify
and destroy virus-
infected cells
Long-lived ‘memory’ B and T cells that
recognize the virus patrol the body for
months or years, providing immunity
B-cell
B-cells make antibodies that block the virus from
infecting more cells and mark it for destruction
T-cells activate other
immune responses
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

8. How vaccines work*
Weakened virus, dead virus, or parts of the virus are introduced into the patient.
Because it is inactive or in pieces, the patient doesn’t develop the disease.
Image credits: https://www.bbc.com/news/world-48186856
The Amoeba Sisters: https://www.amoebasisters.com/
*simplified

9. How vaccines work*
Image credit: The Amoeba Sisters: https://
www.amoebasisters.com/
Immune system cells mount a response to fight the attenuated virus
*simplified

10. How vaccines work*
The immune system retains memory of the pathogen and can mount an attack
more quickly and efficiently.
Image credit: The Amoeba Sisters: https://
www.amoebasisters.com/
*simplified

11. Types of vaccines: whole virus vaccines
These vaccines use a weakened or inactivated virus to produce an immune
response
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

12. Types of vaccines: whole virus vaccines
These vaccines use a weakened or inactivated virus to produce an immune
response
The virus is weakened or
inactivated
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

13. Types of vaccines: whole virus vaccines
These vaccines use a weakened or inactivated virus to produce an immune
response
The virus is weakened or
inactivated
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

14. Types of vaccines: whole virus vaccines
These vaccines use a weakened or inactivated virus to produce an immune
response
Antigen presenting cells take up the virus, break it into pieces,
and ‘present’ those pieces to other immune system cells.
The virus is weakened or
inactivated
Immune
response
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

15. Types of vaccines: whole virus vaccines
These vaccines use a weakened or inactivated virus to produce an immune
response
Examples: MMR, smallpox, yellow
fever, chickenpox, flu
Antigen presenting cells take up the virus, break it into pieces,
and ‘present’ those pieces to other immune system cells.
The virus is weakened or
inactivated
Immune
response
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

16. Types of vaccines: protein-based vaccines
Instead of the entire virus, only certain components that best stimulate the
immune system (called antigens) are used
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

17. Types of vaccines: protein-based vaccines
Instead of the entire virus, only certain components that best stimulate the
immune system (called antigens) are used
Pieces of viral proteins (such as the virus
spike or shell proteins) are administered
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

18. Types of vaccines: protein-based vaccines
Instead of the entire virus, only certain components that best stimulate the
immune system (called antigens) are used
Pieces of viral proteins (such as the virus
spike or shell proteins) are administered
Immune
response
Antigen presenting cells take up the viral
proteins, break them into pieces, and ‘present’
those pieces to other immune system cells.
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

19. Types of vaccines: protein-based vaccines
Instead of the entire virus, only certain components that best stimulate the
immune system (called antigens) are used
Pieces of viral proteins (such as the virus
spike or shell proteins) are administered
Immune
response
Antigen presenting cells take up the viral
proteins, break them into pieces, and ‘present’
those pieces to other immune system cells.
Examples: hepatitis B, HPV, whooping
cough, shingles
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

20. Types of vaccines: DNA vaccines
Vaccines that use genetic instructions (in the form of DNA) to make a viral protein
that prompts an immune response
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

21. Types of vaccines: DNA vaccines
Vaccines that use genetic instructions (in the form of DNA) to make a viral protein
that prompts an immune response
DNA encoding viral proteins (e.g.
the spike protein) is inserted into
a circular piece of DNA called a
plasmid
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

22. Types of vaccines: DNA vaccines
Vaccines that use genetic instructions (in the form of DNA) to make a viral protein
that prompts an immune response
DNA encoding viral proteins (e.g.
the spike protein) is inserted into
a circular piece of DNA called a
plasmid
mRNA
Our cells take up the
DNA and use it to make
viral proteins
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

23. Types of vaccines: DNA vaccines
Vaccines that use genetic instructions (in the form of DNA) to make a viral protein
that prompts an immune response
DNA encoding viral proteins (e.g.
the spike protein) is inserted into
a circular piece of DNA called a
plasmid
Immune
response
Antigen presenting cells take up the
viral proteins, break them into pieces,
and ‘present’ those pieces to other
immune system cells.
mRNA
Our cells take up the
DNA and use it to make
viral proteins
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

24. Types of vaccines: DNA vaccines
Vaccines that use genetic instructions (in the form of DNA) to make a viral protein
that prompts an immune response
Examples: West Nile virus in horses
None yet for human use
DNA encoding viral proteins (e.g.
the spike protein) is inserted into
a circular piece of DNA called a
plasmid
Immune
response
Antigen presenting cells take up the
viral proteins, break them into pieces,
and ‘present’ those pieces to other
immune system cells.
mRNA
Our cells take up the
DNA and use it to make
viral proteins
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

25. Types of vaccines: RNA vaccines
Vaccines that use genetic instructions (in the form of RNA) to make a viral protein
that prompts an immune response
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

26. Types of vaccines: RNA vaccines
Vaccines that use genetic instructions (in the form of RNA) to make a viral protein
that prompts an immune response
RNA encoding viral proteins (e.g.
the spike protein) is encased in a
lipid coat so it can enter cells
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

27. Types of vaccines: RNA vaccines
Vaccines that use genetic instructions (in the form of RNA) to make a viral protein
that prompts an immune response
RNA encoding viral proteins (e.g.
the spike protein) is encased in a
lipid coat so it can enter cells
Our cells take up the
RNA and use it to make
viral proteins
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

28. Types of vaccines: RNA vaccines
Vaccines that use genetic instructions (in the form of RNA) to make a viral protein
that prompts an immune response
Immune
response
Antigen presenting cells take up the
viral proteins, break them into pieces,
and ‘present’ those pieces to other
immune system cells.
RNA encoding viral proteins (e.g.
the spike protein) is encased in a
lipid coat so it can enter cells
Our cells take up the
RNA and use it to make
viral proteins
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

29. Types of vaccines: RNA vaccines
Vaccines that use genetic instructions (in the form of RNA) to make a viral protein
that prompts an immune response
RNA vaccines are still under development and none have yet been approved for use in humans
Immune
response
Antigen presenting cells take up the
viral proteins, break them into pieces,
and ‘present’ those pieces to other
immune system cells.
RNA encoding viral proteins (e.g.
the spike protein) is encased in a
lipid coat so it can enter cells
Our cells take up the
RNA and use it to make
viral proteins
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

30. Types of vaccines: viral vectors
These vaccines use a different virus (that doesn’t cause disease) to deliver
coronavirus genes into the cell and provoke an immune response
Genes encoding viral proteins
(e.g. the spike protein) are placed
into a non-disease causing virus
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

31. Types of vaccines: viral vectors
These vaccines use a different virus (that doesn’t cause disease) to deliver
coronavirus genes into the cell and provoke an immune response
Genes encoding viral proteins
(e.g. the spike protein) are placed
into a non-disease causing virus
The non-disease
causing virus replicates
within our cells
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

32. Immune
response
Antigen presenting cells take up the
virus, break it into pieces (which
include pieces of coronavirus
proteins), and ‘present’ those pieces
to other immune system cells.
Types of vaccines: viral vectors
These vaccines use a different virus (that doesn’t cause disease) to deliver
coronavirus genes into the cell and provoke an immune response
Genes encoding viral proteins
(e.g. the spike protein) are placed
into a non-disease causing virus
The non-disease
causing virus replicates
within our cells
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

33. Immune
response
Antigen presenting cells take up the
virus, break it into pieces (which
include pieces of coronavirus
proteins), and ‘present’ those pieces
to other immune system cells.
Types of vaccines: viral vectors
These vaccines use a different virus (that doesn’t cause disease) to deliver
coronavirus genes into the cell and provoke an immune response
Example: Newly approved
Ebola vaccine
Genes encoding viral proteins
(e.g. the spike protein) are placed
into a non-disease causing virus
The non-disease
causing virus replicates
within our cells
Content: https://www.nature.com/articles/d41586-020-01221-y
Virus image: https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

34. Stages of vaccine development
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
1-10 years 2-3 years 2-4 years > 1 year
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

35. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
1-10 years 2-3 years 2-4 years > 1 year
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

36. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Preclinical testing: scientists give the vaccine to animals such as mice or monkeys to see
if it produces an immune response
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

37. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Phase I safety trials: scientists give the vaccine to a small number of people to test safety
and dosage and to confirm that it stimulates the immune system
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

38. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Phase II expanded trials: scientists give the vaccine to hundreds of people split into
groups, such as children and the elderly, to see if the vaccine acts differently in them. These
trials further test the vaccine’s safety and ability to stimulate the immune system.
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

39. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Phase II expanded trials: To accelerate the vaccine development timeline, there are
several vaccines combining Phase I and II trials
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

40. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Phase III efficacy trials: scientists give the vaccine to thousands of people and wait to see
how many become infected compared with volunteers who received a placebo. These trials
can determine if the vaccine protects against the coronavirus
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

41. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Approval: Regulators in each country review the trial results and decide whether to approve
the vaccine or not. During a pandemic, a vaccine may receive emergency use authorization
before getting formal approval.
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

42. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
There is 1 vaccine that is currently in Phase III trials and has limited approval for use in
the Chinese military as a “specially needed drug.”
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)31605-6/fulltext
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

43. Stages of vaccine development*
Exploratory Preclinical Phase I Phase II Phase III Approval Surveillance
Safety &
dosage
testing
Expanded
safety trials
Large-scale
efficacy
tests
Approved
for limited
use
Animal trials
Usually it takes years to develop a vaccine, but scientists are racing to produce a
safe and effective vaccine by next year
135+ 21 13 8 2 0
Russia approved a vaccine that has completed Phase II trials (but hasn’t begun Phase III). However, trial
data have not been published and vaccine experts worry about about safety and efficacy.
https://edition.cnn.com/2020/08/11/europe/russia-coronavirus-vaccine-putin-intl/index.html
https://www.bbc.com/news/world-europe-53751017
*August 23rd 2020
https://www.who.int/biologicals/BS2287_Clinical_guidelines_final_LINE_NOs_20_July_2016.pdf?ua=1
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html

44. Example of a promising candidate
mRNA vaccine. Teaches human cells to build the spike proteins, which
triggers an immune response.
Results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true

45. Example of a promising candidate
mRNA vaccine. Teaches human cells to build the spike proteins, which
triggers an immune response.
Phase I trial results published on July 14th 2020
Safety &
dosage
testing
Results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true

46. Example of a promising candidate
mRNA vaccine. Teaches human cells to build the spike proteins, which
triggers an immune response.
Phase I trial results published on July 14th 2020
Safety &
dosage
testing
Generally safe and well-tolerated, but ~1/2 had some mild/moderate side effects (e.g.,
fatigue, headache, chills). High dose that caused the strongest side effects won’t be
used in subsequent trials.
Results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true

47. Example of a promising candidate
mRNA vaccine. Teaches human cells to build the spike proteins, which
triggers an immune response.
Phase I trial results published on July 14th 2020
Safety &
dosage
testing
Generally safe and well-tolerated, but ~1/2 had some mild/moderate side effects (e.g.,
fatigue, headache, chills). High dose that caused the strongest side effects won’t be
used in subsequent trials.
Phase II is ongoing. Phase III trials started July 27th, 2020 with a target of
30,000 individuals.
Large-scale
efficacy
tests
Results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true

48. Moderna vaccine: phase I experiment
Results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true
45 healthy adults
18-55 years of age
25 µg dose
100 µg dose
250 µg dose
15 individuals
15 individuals
15 individuals
Day1
Z
25 µg dose
100 µg dose
250 µg dose
Day29

49. Moderna vaccine: phase I results*
Key result: the vaccine provoked a strong immune response
Antibodiesproduced
Less
More
Pre-injection
Recovered
patient
All results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true
*Simplified. See linked
paper for full results

50. Moderna vaccine: phase I results*
Key result: the vaccine provoked a strong immune response
Antibodiesproduced
Less
More
Pre-injection
Recovered
patient
After 1st dose
All results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true
*Simplified. See linked
paper for full results

51. Moderna vaccine: phase I results*
Key result: the vaccine provoked a strong immune response
Antibodiesproduced
Less
More
Pre-injection
Recovered
patient
After 1st dose
After 2nd
dose
All results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true
*Simplified. See linked
paper for full results

52. Moderna vaccine: phase I results*
Key result: the vaccine provoked a strong immune response
Antibodiesproduced
Less
More
Pre-injection
Recovered
patient
After 1st dose
After 2nd
dose
All results from phase I trial: https://www.nejm.org/doi/pdf/10.1056/NEJMoa2022483?articleTools=true
*Simplified. See linked
paper for full results
Note that Phase I trials do not evaluate efficacy. Producing an immune
response does not guarantee immunity if exposed to the virus. Phase III
trials are designed for efficacy testing.