What Is the Beta Variant?

What to know about this COVID-19 mutation, also known as the B.1.351 variant

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

Since the start of the COVID-19 pandemic, multiple variants of the virus have developed, including the B.1.351 variant—which was initially discovered in South Africa in December 2020.

Virus Background

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Where Beta Has Spread

The B.1.351 variant, which is also known as the Beta variant, spread to at least 115 countries worldwide, including the United States.

Spread in the United States

The Beta variant was initially found in the United States in January 2021, with the first case found in the state of Washington. As of April 21, 2021, there were less than 500 total confirmed cases of the Beta variant in the United States; it has been documented in 36 states.

As of June 15, 2021, the variant accounted for between .1% to 2.6% of cases in states where it's found.

Why Do Viruses Mutate?

It is common for all viruses to mutate. When a virus enters the body, it begins to make copies of itself.

Sometimes during this process, mistakes (mutations) are made in the copies, which can make it easier for the virus to invade the cell. When this same mutation continues to further copy itself, a variant of the virus forms.

Is Beta More Contagious?

The Beta variant is thought to be more contagious than the original COVID-19 virus. The Centers for Disease Control and Prevention (CDC) estimates a 50% increased transmission rate of COVID-19 from the Beta variant.

The infectiousness of a virus is measured by an R number, or the number of people an infected person will give the virus to. For example, if the R is 1, an infected person is likely to give it to one other person; an R of 5 means an infected person is going to transmit it to five other people.

Preventing Transmission

Precautions to prevent the transmission of the Beta variant are the same as for the original COVID-19 virus and should continue to be followed. Precautions if you're unvaccinated include:

  • Stay 6 feet apart from others who don’t live in your household
  • Wear a mask that covers your mouth and nose
  • Practice good hand hygiene by washing hands often or using hand sanitizer  

If you are fully vaccinated, the CDC has released new guidelines that say it is safe to go without a mask and physical distancing in places where it isn't required by federal, state, or local regulations. Regular hand washing is still recommended.

Risk of Reinfection

It is possible that the Beta variant can cause reinfection. Studies have shown that natural immunity from previous COVID-19 infection does not protect well against this variant, but there is limited data to support the risk of reinfection at this time.

Is Beta More Severe?

Evidence comparing COVID-19 hospitalization and severity from the original COVID-19 virus versus the Beta variant in South Africa showed that there was an increase in mortality rate in those with the Beta variant.

This was a small study and other studies have not found this variant to cause more severe COVID-19.

Other studies uncovered that specific monoclonal antibody treatments may be less effective for treating cases of COVID-19 caused by the Beta variant.

Do Vaccines Work Against Beta?

The World Health Organization (WHO) has reported that the Beta variant does cause a decrease in the effectiveness of vaccines.

Regarding the Pfizer and Moderna vaccines, the studies have had various outcomes on the total reduction of effectiveness, from very little reduction to more substantial reduction. The Johnson & Johnson vaccine has shown to be 85% effective at preventing severe COVID-19, which included regions with the Beta variant.

Are Kids More At Risk for Beta?

There is little data currently available for the risk of Beta in children. The virus has been documented in at least one child in the United States, however there is no evidence suggesting this virus causes more severe disease in children and does not suggest increased infection among children.

A Word From Verywell

Following precautions as outlined by the CDC and getting a vaccine when it is available to you—as long as it safe for you to do so—is important to help decrease the spread of this and other variants of COVID-19.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Science brief: emerging SARS-CoV-2 variants.

  2. World Health Organization. Weekly epidemiological update on COVID-19 week—15, June 2021

  3. Washington State Department of Health. First case of B.1.351 variant identified in Washington state as cases of B.1.1.7 increase.

  4. Centers for Disease Control and Prevention. US COVID-19 cases caused by variants.

  5. Centers for Disease Control and Prevention. COVID-19 data tracker: variant proportions.

  6. Cleveland Clinic. What to know about the latest COVID-19 variant and other coronavirus mutations.

  7. Centers for Disease Control and Prevention. SARS-CoV-2 variant classifications and definitions.

  8. Zhou D, Dejnirattisai W, Supasa P, et al. Evidence of escape of SARS-CoV-2 variant B.1.351 from natural and vaccine-induced sera. Cell. 2021;184(9):2348-2361.e6. doi:10.1016/j.cell.2021.02.037

  9. Centers for Disease Control and Prevention. How to protect yourself & others.

  10. Centers for Disease Control and Prevention. When you've been fully vaccinated. Updated June 17, 2021.

  11. Zucman N, Uhel F, Descamps D, Roux D, Ricard J-D. Severe reinfection with South African severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant 501y. V2Clin Infect Dis. Published online February 10, 2021. doi:10.1093/cid/ciab129

  12. Jassat W, Mudara C, Ozougwu L, et al. Increased mortality among individuals hospitalised with COVID-19 during the second wave in South AfricamedRxiv. Published online March 10, 2021. doi:2021.03.09.21253184

  13. Johnson & Johnson. Johnson & Johnson COVID-19 vaccine authorized by U.S. FDA for emergency use-first single-shot vaccine in fight against global pandemic.

By Julie Scott, MSN, ANP-BC, AOCNP
Julie is an Adult Nurse Practitioner with oncology certification and a healthcare freelance writer with an interest in educating patients and the healthcare community.