This document discusses vaccines, how they work, their importance, and herd immunity. It begins by asking why we need vaccines and then explains that vaccines train the immune system to recognize pathogens and produce antibodies to fight them off. It describes the different types of vaccines, including mRNA, viral vectors, protein subunit, and live attenuated virus. It defines vaccination as using the immune system to build resistance before exposure. The document stresses that vaccination is important both to protect individuals and society by achieving herd immunity once a high percentage of the population is vaccinated.

2. Why do we need vaccines?
What are vaccines? How do vaccines work?
Which are the different types of vaccines?
What is vaccination?
How does vaccination protect us?
Why is vaccination important?
What is herd or population immunity?
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3. Why do we need
vaccines?

4. Why do we need vaccines?
Virus, bacteria, parasites.
They are all external agents (‘pathogens’)
that can attack our bodies.

5. Vaccines are, in a way, victims of
their own success.
Most of us have already been vaccinated against
polio, measles, meningitis, to name a few
devastating diseases.
Why do we need vaccines?

6. What are vaccines?
How do they work?

7. What are vaccines? How do they work?
Our body has natural defenses -the
immune system- that have learned
and stocked all the information
specific to each pathogen.

8. What are vaccines? How do they work?
The immune system got all that data
by either having contacted specific
components of the pathogens
(antigens) or after receiving a vaccine.

9. To make our body ready to defend
against future, potential disease-causing
pathogens, vaccines train the immune
system to produce antibodies,
specialized proteins that bind to the
invader’s antigens and neutralize them.
What are vaccines? How do they work?
PATHOGEN ANTIBODIES
EXISTING
PATHOGEN
ANTIGEN
EXISTING
PATHOGEN
ANTIGEN
NEW
PATHOGEN
EXISTING
ANTIBODY
EXISTING
ANTIBODY
ANTIBODY IN
PROCESS

10. When we receive a vaccine, the immune
system recognizes the components of the
pathogen and it stores them in its “library”.
What are vaccines? How do they work?

11. Vaccines mimic infectious agents:
contain only killed, weakened, or a part
of, pathogens capable of triggering a
defense by our immune system in
preparation for an eventual contact
with the actual infectious agent,
without risk of us becoming sick. By
teaching our immune system to
recognize and fight off pathogens,
vaccines help our body defend itself
every time it feels attacked.
What are vaccines? How do they work?

12. Which are the
different types of
vaccines?

13. VACCINES THAT USE mRNA
mRNA is the mold upon which all living cells make proteins.
SARS-CoV-2, the virus that causes COVID-19, is no more than
mRNA surrounded by a capsule. On the surface of this
capsule we can find the so-called Spike Protein that the virus
uses to attach itself to the cells in the human respiratory tract,
and so enter the body and cause infection. Of all the viral
mRNA, only a fragment is needed to form the spike protein.
The mRNA vaccines (Pfizer and Moderna) only inject this
fragment into the muscles of those who receive it. The
injected mRNA will disappear within three days.
Which are the different types of vaccines?

14. VACCINES THAT USE DNA
We said that SARS-CoV-2 uses mRNA, not DNA. However, the
fragment that molds the Spike Protein can be attached to the
DNA of a virus that does not cause disease in humans, but
can transport the relevant material into the cells. Several
strains of adenovirus are used to achieve this goal:
chimpanzee adenovirus 8 (Oxford/Astra Zeneca) and
adenovirus 26 (Sputnik 5 and Johnson & Johnson). The
injected adenovirus is programmed to have a limited
replication to amplify the response without causing disease in
those who gets the vaccine.
Which are the different types of vaccines?

15. VACCINES THAT INJECT THE SPIKE PROTEIN
This type of vaccine is more similar to the one we use for
diseases like tetanus. The spike is produced in large
amounts and out of the body, and is then injected. Defense
cells recognize the protein and form antibodies against it.
So far, Novavax is the only company working on this
product.
Which are the different types of vaccines?

16. VACCINES THAT INJECT DEAD VIRUS
The oldest vaccines develop viruses in the laboratory and
then weaken or kill them keeping enough integrity for the
body to create antibodies against the natural virus. This
type of vaccine is not being developed in the USA (studied
in India and China, for example)
Which are the different types of vaccines?

17. COMPANY TYPE
Pfizer
Moderna
Oxford/
AstraZeneca
Johnson & Johnson
Novavax
Sputnik V
mRNA
mRNA
Andenovirus
vector
Andenovirus
vector
Andenovirus
vector
Andenovirus
vector
DOSE
2
2
2
1
2
2
95%
95%
62-90%
70%
90%
92%
-70ºC
-20ºC
Regular Refrigerator
Regular Refrigerator
Regular Refrigerator
Regular Refrigerator
Which are the different types of vaccines?
EFFICACY STORAGE

18. What is
vaccination?

19. Vaccination is a simple, safe and effective way of
protecting people against harmful diseases before
they come into contact with them. It uses our body’s
immune system to build resistance to specific
infections.
What is vaccination?

20. How does vaccination
protect us?

21. How does vaccination protect us?
After the initial exposure to an antigen
the immune system needs time to
produce antibodies. In the meantime, the
person can become sick. This is what is
currently happening with the virus that
causes Covid-19.

22. How does vaccination protect us?
It is the first time that this pathogen
is in contact with the global
population and people still do not
have the immune system prepared
to face it in an effective way. For this
reason, the infections multiply rapidly,
and the planet must confront itself
with a pandemic that is very hard to
control. Developing vaccines is one of
the most effective strategies to
confront the Covid-19 pandemic.

23. Why is vaccination
important?

24. Why is vaccination important?
01. 02.
Vaccination is the strategy
that we have as a society to
create a collective memory
in our immune system
facing this new disease.
A massive vaccination
campaign is essential for the
whole world population to
confront the coronavirus that
causes Covid-19, stopping its
spread and avoiding
sickness.

25. What is herd or
population
immunity?

26. What is herd or population immunity?
When somebody is vaccinated, it is very
probable that he/she is protected (immune)
against the illness that the pathogen could
cause.
Unfortunately, not everyone can receive
vaccines: Some people, like
those who are seriously ill, are advised
not to get vaccinated; they are
considered ‘vulnerable’. These people
can still be protected if they live among
other people who are vaccinated.

27. The more that are immune in a community,
the less likely those who remain vulnerable
run the risk of being exposed to the harmful
pathogens. This is what is called herd or
population immunity.
What is herd or population immunity?

28. 80% PEOPLE VACCINATED
What is herd or population immunity?
When we get vaccinated, we are not just protecting
ourselves, but also those around us.
20% PEOPLE VACCINATED
Vaccinated
Susceptible Vulnerable

29. Don’t forget! Immunization programs are only
successful when there are high rates of
acceptance and coverage.
The vaccine protects you, but it also protects
those people who cannot be vaccinated for
various reasons.
Get vaccinated and feel the
importance of your contribution in
doing so.
What is herd or population immunity?

30. ➔ www.coverorcovid.org
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