We’re more than two years into the COVID-19 pandemic, and as we continue to learn more about the virus, new information on variant strains remains a significant concern for healthcare providers and the public. As healthcare providers, we constantly receive questions regarding variants. How did they evolve? What do we know about the variants? How do they impact existing immunizations, and which vaccines are proven to be effective against COVID-19? Here’s what we currently know.
How did these variants evolve?
- Viruses mutate constantly, with new variants developing over time. Viral mutations may lead to increased ease of transmission and infectivity, and evade the host’s natural immune response. This is a normal, expected process.
- All viruses consist of a group of either DNA or RNA genetic material that is covered by a protective coating of proteins. A virus’s usual port of entry is the mouth or nose, where it latches onto the cells. The virus’s DNA or RNA enters the cell, copies itself and infects other cells.
- Mutations develop when an error occurs in the viral copying process. When these copying errors take place, they may become part of the virus’s normal genome over time. This process leads to the birth of new variant strains of the virus.
- Scientists closely monitor viruses for mutations and perform genetic analyses to better understand the effect of viral mutations on the population, the viral spread and those infected.
- In the case of COVID-19, variants contain mutations of the spike-like S protein of the virus, leading to the variant’s increased ability to bind to and infect cells.
- Multiple variants are present in the United States and globally. Variants are expected to occur, but vaccination remains one of our most important weapons in the battle against COVID-19. Vaccination helps prevent the occurrence of new variants over time.
What do we know about variants?
- Variants are currently labeled by scientists to avoid noting specific geographical locations that may cause social, cultural or economic stigmas. The World Health Organization is in the process of determining how to best label variants in the simplest way possible.
- A SARS-CoV-2 Interagency Group (SIG) was created to improve communication among the U.S. Centers for Disease Control and Prevention (CDC), National Institutes of Health, U.S. Food and Drug Administration, Biomedical Advanced Research and Development Authority, and Department of Defense. The focus of this group’s work is the quick characterization of emerging variants. They also monitor the variants’ impact on countermeasures such as vaccines, treatments and diagnostics.
- SIG and CDC have created a classification system for variants in four categories: Variant Being Monitored, Variant of Interest, Variant of Concern and Variant of High Consequence. To see a current list of variants in each category, visit Variant Being Monitored on the CDS website
- A Variant Being Monitored means that data indicates there may be potential impact on approved and/or authorized medical countermeasures. These variants have been associated with severe disease or an increased transmission of disease, but are no longer detected or circulating at low levels in the United States.
- A Variant of Interest has specific genetic markers known to alter receptor binding and may cause decreased neutralization by antibodies generated against an infection or vaccination, may reduce the efficacy of treatments, may have a potential diagnostic impact, and may increase transmissibility and disease severity.
- A Variant of Concern is classified as a result of the following characteristics: There is evidence of increased transmissibility, more severe disease, a significant reduction in the neutralization of antibodies generated during a previous infection or vaccination, decreased effectiveness of treatments and vaccines, and diagnostic detection failure.
- A Variants of High Consequence is a result of demonstrated failure of diagnostics, evidence indicating a significant reduction in vaccine effectiveness, a high number of vaccine breakthrough cases, low vaccine-induced protection against severe disease, more severe clinical disease, increased hospitalizations and significantly reduced susceptibility to multiple emergency use authorizations or approved therapeutics.
- At this time, there are no variants in the Variant of High Consequence classification.
Timeline of Variants and Their Global Impact
- September 2020: Variant B.1.1.7 (alpha) was discovered in the United Kingdom.
- October 2020: Variant B.1.617.2 (delta) was first documented in India.
- December 2020: The first variant B.1.1.7 case was diagnosed in the United States; variant B.1.351 (beta) was discovered in South Africa.
- January 2021: Variant B.1.351 (beta) was first diagnosed in the United States; variant P.1 (gamma) was identified in Japan in travelers from Brazil; variant B.1.621 and B.1.621.1 (mu) was first noted in Colombia.
- February 2021: Variants B.1.427 and B.1.429 (epsilon) were identified in California.
- March 2021: The CDC closely monitored potential variants B.1.525 (eta) and B.1.526 (iota) in New York, as well as variant P.2 (zeta) in Brazil.
- November 2021: Variant B.1.1.529 (omicron) was first detected in South Africa.
- December 2021: Variant B.1.1.529 (omicron) was first diagnosed in the United States.
How do variants impact existing vaccinations?
- Current COVID-19 immunizations were created based on the SARS-CoV-2 S protein before mutations were identified in variants.
- To date, research notes that although current immunizations may have decreased efficacy against variants, receiving the vaccine decreases the risk of severe illness, hospitalization and death as a result of COVID-19.
- Ongoing research is focused on the impact of variants on current vaccinations, but it is likely that vaccinations will need to be continually updated as the virus progresses.
- Compliance with public health mitigation strategies remains essential to help prevent the spread of variants. These strategies include vaccination, social distancing, hand hygiene, use of masks, testing, and isolation and quarantine in those known to have, or have been exposed to, the virus.
As of the date of this blog, the latest vaccination recommendations now include COVID-19 booster shots for adults ages 18 and older, as well as for teenagers between the ages of 16 and 17 years at least six months after their initial Pfizer-BioNTech vaccination series. For the most current vaccination recommendations, please visit the CDC webpage Key Things to Know About COVID-19 Vaccines.
Because of the ever-evolving nature of the COVID-19 pandemic, additional monitoring and research is ongoing. The CDC provides regularly updated information concerning COVID-19 variants for the public and healthcare providers.
How have COVID-19 variants impacted your practice? What trends are you noting in your community?