In a little more than a year since the start of the global COVID-19 pandemic, more than 500,000 American lives have been lost.

We passed this grim number within the last week. As we enter spring in the coming month, both infection and death rates are on the decline because of multiple factors, ranging from the season to public health measures and the impact of safe and effective vaccines.

While there are signs of hope, it is clear that challenges lie ahead. In recent months, emerging variants of the virus have begun to pop up around the globe – first in the United Kingdom and South Africa, and also in Brazil. Considerable effort is underway to better understand these variants and their potential impact as we move into the spring and summer months.

The SARS-CoV-2 virus that causes COVID-19 is not unlike its coronavirus cousins in that it is susceptible, like many viruses, to constant mutation. While most mutations are insignificant in terms of the risk of disease spread or severity, some mutations confer a benefit to the virus.

The current emerging variants from the U.K., South Africa and Brazil all share one thing in common, which is mutation in the viral spike protein.

The spike protein is the part of the virus that attaches itself to the human cell and permits entry of the virus. It is also the target of important antibodies produced by infected people to fight off the virus or prevent re-infection. Finally, the spike protein is the target of COVID vaccines currently authorized for use in the United States.

To be clear, there are many potential mutations in the spike protein, some of which are more important than others. Depending on the mutation, various effects may include increased rate of transmission (easier to get infected), increased disease severity (higher risk of serious illness) and effectiveness of certain treatments (monoclonal antibodies) or vaccines.

According to the Centers for Disease Control and Prevention, early studies of the U.K. and South African emerging variants, while not conclusive at this point, indicate that the mutations do not lead to increased disease severity. Early studies of the Brazilian variant suggest possible increased transmissibility and potential increased risk for reinfection.

Besides public health measures, such as social distancing, hand washing and mask wearing, the best tool we have right now to combat emerging variants is vaccination. Both the Pfizer/BioNTech and Moderna vaccines appear effective against both the U.K. and (to a slightly lesser extent) South African variants. Meanwhile, the new Johnson & Johnson vaccine showed similar effectiveness in studies in the U.S., South Africa and Brazil, which were being conducted during a time after emergence of the mutant variants.

More importantly, current vaccine technology should allow scientists to update vaccines if needed to address the threat of virus mutations.

COVID vaccines have proven both safe and effective in combatting the pandemic.

Dr. Matthew A. Clark is a board-certified physician in internal medicine and pediatrics practicing at the Ute Mountain Ute Health Center in Towaoc.