Effects of COVID-19 Variants on Vaccine Efficacy

Some people think that once vaccines are fully distributed to the population COVID-19 will become obsolete. Which in theory because of herd immunity makes sense; however, in reality due to slow vaccine rollout from many countries it may not be so cut and dry. Vaccines can be extremely beneficial to help your body gain antibodies to fight a virus though they can only be effective if there are little or no mutations in the virus. This is concerning, as ever since the first cases of COVID-19 were discovered in China there have been 3 new variants which have mutated in locations such as the United Kingdom, Brazil and South Africa.[1] The UK variant known as B.1.1.7 was first found during fall 2020 in the UK and has 8 known mutations. [1][2] This variant is thought to spread faster and easier than other variants.[1] The Brazil variant known as P.1 was found in early January and reportedly may have varying ability to be recognized by antibodies although not much is known as it was discovered recently.[1] Finally, the South Africa variant known as B.1.351 was found during October 2020 and it has many similar properties to the UK variant although it has 9 known mutations.[1][2] As of January 2021, these variants have all spread to other countries around the world including the Unites States of America.[1]

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One study found that the Novavax vaccine was 85.6% effective in a UK trial however it was only 49.4% effective in a South Africa trial (where the B.1.351 variant is prevalent).[2] This is very troubling though, the Novavax vaccine is not the only vaccine whose efficacy is dropping due to new variants. A new study from Columbia University found that Moderna and Pfizer vaccines were significantly less effective at neutralizing the UK and South African variants.[2] Specifically, it was found that neutralization of the virus decreased by a degree of 2 in the UK variant and by a degree of 6.5-8.5 in the South African variant.[2] This neutralizing ability has been shown to be linked with the efficacy of vaccines so the decrease in neutralization is especially concerning.[2] This study was performed by creating harmless non-infectious viruses that create the coronavirus spike protein (pseudoviruses) and observing sensitivity to serum from previously infected patients, serum from people vaccinated with Pfizer or Moderna and 18 different antibodies that are monoclonal.[2] Of these 18 antibodies 2 of them were impaired against the UK variant and 4 of them lost their ability to neutralize against the South African variant.[2] In the same study the serum from previously infected patients had 4 times less neutralizing activity against the UK variant and 11 times less neutralizing activity against the South African variant.[2] Thus, demonstrating these new variants (in particular the South Africa variant) will also likely increase the risk of reinfection.[2]

Consequently, if the virus continues to spread and mutate it is possible that it may become similar to influenza in which a new vaccine must be created every year to keep with its evolving nature.[2] Therefore, it is important to stop the spread of the virus by increasing speed of rollout of vaccines, wearing masks and physically distancing whenever possible.

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References

1. Centers for Disease control and Prevention. (2021, February 12). About Variants that Causes COVID-19. Retrieved March 22, 2021 from https://www.cdc.gov/coronavirus/2019-ncov/transmission/variant.html

2. Columbia University Irving Medical Center. (2021, March 8). Study of coronavirus variants predicts virus evolving to escape current vaccines. ScienceDaily. Retrieved March 20, 2021 from www.sciencedaily.com/releases/2021/03/210308131712.htm

3. Pan American Health Organization. (2021). [Photograph of COVID-19 vaccine]. PAHO. https://www.paho.org/en/news/31-1-2021-countries-americas-notified-first-covid-19-vaccine-allocations-through-covax

4. Thomson, C. (2021). [Computer generated view of Coronavirus]. CTV News. https://kitchener.ctvnews.ca/over-200-cases-identified-as-variants-of-concern-in-waterloo-region-1.5346816