Understanding COVID-19 Variants

Information in this article may have changed since the original publish date. Please refer to the CDC for the most up-to-date information.

All viruses change over time, including the one that created the COVID-19 pandemic (SARS-CoV-2).

But how are these variants created? How many are there in the U.S.? More importantly, how do we stop them from spreading? For answers to these and other questions about the emerging COVID-19 variants in our country and in other parts of the world, we’ve provided a list below.

The good news is the vaccines authorized for use in the United States (Pfizer, Moderna and Johnson & Johnson) are doing what they were designed to do—they’re working. Even against the variants. But the challenge remains to get at least 70% of the U.S. population vaccinated and, eventually, the rest of the world.

How are variants created?

For any virus to grow in our bodies, it must reproduce itself—not just hundreds of times, or thousands of times—but hundreds of thousands of times. With this much replication, there’s a good chance the virus will mutate. These mutations can create different variants.

Do all viruses change?

Yes. All viruses evolve. So it’s natural that the virus that causes COVID-19 mutated and created variants. The key is for health organizations, like the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO), to continually monitor changes to the virus to know how to respond. More importantly, we all need to do our part to help prevent variants from spreading.

Why do we need to keep track of emerging variants?

Health organizations like the CDC and WHO monitor emerging variants to determine if the variants can:

  • Spread more quickly
  • Cause more severe disease
  • Evade detection by specific tests
  • Evade natural or vaccine-induced immunity

How can we prevent COVID-19 variants from spreading?

The more the virus spreads, the more opportunity there is for variants to emerge. There are two ways to stop this from happening:

  • Get vaccinated — this is the most effective way to prevent the spread of COVID-19 and its variants.
  • Prevent infection continue to wear masks, practice social distancing and wash your hands regularly.

Do I still need to wear a mask if I’m fully vaccinated?

If you’re fully vaccinated, the CDC recommends that you continue to wear a mask in public indoor settings in areas of high or substantial transmission. They also recommend you wear a mask if you’re immunocompromised or live with someone who is.

Fully vaccinated people should also continue to wear a mask where required by federal, state, local, tribal, or territorial laws, rules, and regulations, including local business and workplace guidance, and in correctional facilities and homeless shelters. Continue to check with the CDC web site for the latest updates.

Do the COVID-19 vaccines protect against new variants of the virus?

According to the CDC, data suggest that all three COVID-19 vaccines (Pfizer, Moderna and Johnson & Johnson) offer protection against COVID-19 and all its current variants. The CDC has a clinical preference for people to receive an mRNA COVID-19 vaccine (Pfizer-BioNTech and Moderna). Unvaccinated people, however, remain vulnerable to severe illness, hospitalization and death from COVID-19 and its variants.

If you had COVID, are you protected against variants?

Unfortunately, people who have already recovered from COVID-19 do not have reliable protection against variants.

Will a booster dose be required to protect against COVID-19 variants?

As of January 6, 2022, booster shots are not required to be considered fully vaccinated. However, the CDC recommends booster shots to protect against COVID-19 and its variants.

Anyone 12 years and older can get a COVID booster. At this time, the Pfizer BioNTech (Pfizer) vaccine is the only one approved as a booster shot for 12- and 17-years-olds. Anyone over the age of 12 who received the Pfizer vaccine is eligible for a booster shot five (5) months after their primary series.

Anyone 18 years and older can get the Moderna Vaccine/Spikevax COVID-19 Vaccine (Spikevax) or Johnson & Johnson booster five (5) months after their second dose of Spikevax or two (2) months after their single dose of Johnson & Johnson.

People who received the Pfizer or Spikevax vaccine and who are moderately or severely immunocompromised (receiving cancer treatment, an organ transplant, a stem cell transplant, advanced or untreated HIV infection), or who have moderate or severe primary immunodeficiency are eligible to receive a second booster five (5) months after their last booster shot.

Why are Greek letters used to name the variants?

The World Health Organization proposed using the Greek alphabet to name new variants to make it easier for the public to discuss and remember them. This naming system reduces the stigma of labeling variants by the location they were first identified (e.g., the U.K. variant, South Africa variant, India variant, etc.). Using Greek letters is also more practical than referring to the scientific names that researchers use, such as B.1.167.2.

Are there variants in the United States?

Yes. There are several variants currently in the United States that the CDC is monitoring. They include Alpha, Beta, Delta, Gamma, Epsilon, Eta, Iota, Kappa, Omicron and Zeta. However, the most dominant of these are the Delta and Omicron variants.

The good news is the vaccines authorized for use in the U.S.—Pfizer BioNTech, Moderna Vaccine/Spikevax COVID-19 Vaccine (Spikevax) and Johnson & Johnson—appear to be highly effective at protecting against severe illness and hospitalization for all variants, including the Delta and Omicron variants.

The CDC has been actively monitoring  variants and will continue to work with other U.S. and global public health and industry partners to learn more. For more information on variant proportions, visit COVID Data Tracker.

If I’m fully vaccinated, can I still get COVID-19 or a variant of the virus?

Yes. The authorized vaccines do not guarantee 100% protection. Still, they are all highly effective at preventing severe illness and hospitalization—even against variants. Current data show that among those fully vaccinated who tested positive for the Delta variant, most were asymptomatic. However, breakthrough cases can occur.