Biology of SARS-CoV-2
Click & Learn
Educator Materials
o Inactive whole virus: Sinovac, Sinopharm
o Protein antigen: Novavax
o DNA: CanSino, AstraZeneca, and Johnson & Johnson
o mRNA: Pfizer, Moderna
• For the “Version 2” worksheet, consider relating student answers to Question 20 to the three tests
(RT-PCR test, antigen test, and antibody test) discussed in the Detection video. Then discuss how
these tests can avoid false positives from certain vaccines.
o The RT-PCR test does not detect the genetic instructions (DNA or mRNA) vaccines because i
t
d
etects a different region of the viral genome than the region that encodes the spike protein
(which is delivered by these vaccines).
To understand the RT-PCR test, students may need additional background on PCR. For a
brief summary of how PCR works, consider showing the Polymerase Chain Reaction
animation. This animation does not show the first step for the RT-PCR test: reverse
t
ranscription (RT), in which the viral RNA is converted to DNA.
You may want to discuss the role of primers with students. As shown in the PCR animation,
primers are short DNA sequences designed to bind a specific region of target DNA. In the RT-
PCR test for SARS-CoV-2, the target region typically does not vary too much (or else the
primers may not bind, causing false negatives) but varies enough to allow SARS-CoV-2 to b
e
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istinguished from other coronaviruses. A common target for primers is the nucleocapsid-
encoding region of the viral genome; for more details on the structure of coronaviruses,
refer to Virus Explorer
.
o Antigen tests typically detect the nucleocapsid protein, which is not present in either the
a
ntigen protein vaccines or the genetic instructions (DNA and mRNA) vaccines. Therefore, thes
e
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accines would not be detected by the antigen tests.
o Many antibody tests detect antibodies for the spike protein, which are produced in response to
all the vaccines in the animation. However, antibody tests are not relevant to Question 20
because they should not be used to detect active viral infections, as antibodies remain long after
t
he virus has been cleared.
o Whether these tests detect the inactive whole virus vaccine varies. The virus is typically
chemically inactivated with chemicals such as formalin and
β-propiolactone. These chemicals
can modify proteins, nucleotides, or both. Depending on the chemical used, certain tests may
give false positives for the inactive whole virus vaccine and others may not.
TEACHING
TIPS
• Consider conducting a formative assessment prior to watching the animations. Some ideas are as
follows:
o Before class, make a list of common misconceptions about SARS-CoV-2 or COVID-19 that you
have become aware of in your community or seen on social media. Include several factu
al
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tatements in the list as well.
■ Invite students to discuss which of these statements are accurate and which are not. Record
their decisions.
■ Revisit the list after viewing the animations. Ask students if they have changed their earlier
decisions about the accuracy of the statements.
o Ask students to make a list of what they know about coronavirus infection, evolution, and
detection. This can be done individually or in pairs.
■ Ask students to share one or two items from their lists with the class. Reinforce that, at this
point, all ideas are to be accepted.
■ After viewing the animations, invite students to address misconceptions they had about
SARS-CoV-2 and COVID-19. Ask students to discuss where some of these misconceptions
may have originated.