Vaccines Appear Effective Against COVID Variants

Like other viruses, the SARS-CoV-2 virus that causes COVID-19 can evolve into new variants, given enough time and enough of a susceptible population. Now that highly effective vaccines have changed the outlook for much of the world as far as the original SARS-CoV-2 virus is concerned, researchers are looking to figure out just how much we can rely on existing vaccines to prevent infection or serious illness in the case of variants.

More virus, more variants

The more a virus circulates in a population, the more people become infected and go on to infect others, and the greater the potential for the virus to mutate into variants. Many variants of SARS-CoV-2 appear to be just as vulnerable, or nearly as vulnerable, to the existing Pfizer-BioNTech, Moderna, and Johnson & Johnson vaccines, although some variants have become of special concern for epidemiologists.

Variants – potentially more transmissible and deadly

Among the variants is the B.1.1.7 variant that emerged in the United Kingdom. B.1.1.7 is about 50 percent more transmissible than the original virus, and it is possibly more severe in its effects. This variant has spread extensively throughout the United States and in other countries far outside the UK.

The B.1.351 variant first made itself known in South Africa. Like the UK variant, it is about 50 percent more transmissible from one person to another. 

The P.1 variant, first identified in Brazil and Japan, has produced more than a dozen unique mutations. Several of these change the receptor-binding domain on the virus’ spike protein, worrying researchers. The spike protein is the mechanism by which the virus binds to human receptor cells and enters the body. 

All these variants have caused illness and death, both where they were first identified and beyond international borders.

Vaccines save lives – even from variants

As of mid-2021, researchers had seen ample proof that at least the mRNA-based Pfizer and Moderna vaccines authorized for emergency use in the US offer about a 95 percent efficiency rate in preventing infection with the original SARS-CoV-2, as well as an unbroken record of preventing life-threatening disease and death.

As for variants, scientists are beginning to agree that current vaccines offer a strong barrier against infection, although perhaps not as high as against the original virus. While it remains too soon to tell with complete certainty, scientists are reasonably confident that current vaccines are highly effective at keeping infection with a variant from leading to serious illness or mortality. 

A growing body of tests supports this supposition. A recent Pfizer studied 44,000 individuals around the world, including a South African cohort exposed to B.1.351. This research concluded that the original Pfizer mRNA vaccine was 100 percent effective at preventing hospitalization and death.