Test Your Knowledge: COVID-19 Variants and Vaccine Efficacy
Published Jun 30, 2026 · Updated Jul 31, 2026 · Editorial Team
A fun quiz to explore how variants emerge and affect vaccine effectiveness.
❓ 10 Questions
⏱️ 5 Minutes
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Question 1 of 100 correct
⏱️ 05:00
QUESTION 1
Which mutation in the SARS-CoV-2 spike protein is most associated with increased transmissibility in the Delta variant?
All Questions in This Quiz
Here is every question waiting for you in this 10-question Science & Tech quiz. Play it in the interactive player above to lock in your answers, see your score and read the explanations.
Which mutation in the SARS-CoV-2 spike protein is most associated with increased transmissibility in the Delta variant?
- A. D614G
- B. L452R
- C. E484K
- D. N501Y
What does the term "immune escape" refer to in the context of COVID-19 variants?
- A. Ability to spread faster
- B. Ability to evade neutralizing antibodies
- C. Ability to cause more severe disease
- D. Ability to replicate in animals
The Omicron variant BA.1 showed a significant reduction in neutralization by sera from people vaccinated with two doses of mRNA vaccine. Approximately what fold reduction was observed compared to the original strain?
- A. 2-fold
- B. 5-fold
- C. 10-20-fold
- D. No reduction
Which of the following best explains why booster doses restore protection against Omicron despite reduced neutralizing antibody levels?
- A. Boosters increase T-cell responses only
- B. Boosters raise antibody titers to overcome immune escape
- C. Boosters change the vaccine target to Omicron spike
- D. Boosters eliminate the need for masks
Which variant was first designated as a Variant of Concern (VOC) by WHO in May 2021?
- A. Alpha
- B. Beta
- C. Gamma
- D. Delta
The "spike protein" of SARS-CoV-2 mediates entry into host cells by binding to which receptor?
- A. ACE2
- B. TMPRSS2
- C. CD4
- D. DPP4
Which statement about T-cell immunity and variants is most accurate?
- A. T-cell epitopes are unaffected by spike mutations
- B. T-cell responses are completely lost against Omicron
- C. T-cell immunity only matters for severe disease
- D. T-cell responses increase transmissibility
What does the term "vaccine efficacy" measure in clinical trials?
- A. Percentage reduction in disease incidence among vaccinated vs placebo
- B. Absolute number of cases prevented
- C. Speed of antibody production
- D. Duration of protection
Which of the following is a reason why the Lambda variant (C.37) did not become a dominant global strain despite initial concerns?
- A. It had lower transmissibility compared to Delta
- B. It was only found in South America
- C. It lacked spike mutations
- D. It was not detectable by PCR
When a new variant emerges, scientists often calculate its "effective reproduction number" (R_eff). What does an R_eff > 1 indicate?
- A. The outbreak will decline
- B. Each infection leads to more than one new case on average
- C. The variant is less transmissible than the original strain
- D. Vaccines are 100% effective against it
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