Vaccines and Variants

The emergence of variants has raised concerns that the virus (SARS‑CoV‑2) could mutate and evade immunity induced by currently available vaccines.75 Viruses constantly mutate and change over time. Variants of the coronavirus that were first detected in the U.K., Brazil and South Africa have spread to dozens of countries, and scientists are working to determine what makes them behave differently from earlier versions. Several variants likely have evolved more efficient ways of binding to and entering cells, a critical step in being able to reproduce and spread throughout the body.75 Many vaccines target the spike protein as a target for the development of antibodies as it is highly conserved.76 These spike proteins line the virus’s surface and play a critical role in docking with and attaching to human cells. Variant changes to the spike protein could result in reduced efficacy of currently deployed vaccines. The variant known as B.1.1.7 was originally identified in the United Kingdom in the fall of 2020.77 Another variant, called B.1.351, was identified in South Africa in October 2020. A third variant called P.1 is thought to have emerged in Brazil, after it was detected in travelers who arrived from the country at an airport in Japan in January of 2021.77

Observations from a study published April 2021 indicate a potential risk of illness after successful vaccination and subsequent infection with variant virus, and support is provided for continued efforts to prevent and diagnose infection and to characterize variants in vaccinated persons.78 Researchers from Pfizer/BioNTech and the University of Texas ran laboratory tests using blood samples from people who received the vaccine and engineered versions of the virus with various mutations in its surface spike protein that resembled those found in several variants.79 The researchers claim that the Pfizer/BioNTech COVID‑19 vaccine is also effective against the more infectious P.1 Brazilian variant. However, it was a small laboratory study and it may not translate to clinical efficacy.79