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You finally got your booster dose of the COVID-19 vaccine; life is getting back to normal, but wait—what are these variants you keep hearing about? Are they contagious? Can they affect you even if you’ve been vaccinated—and boosted? Keep reading for what we know right now about new COVID-19 variants.

What COVID variants have been found in the U.S.?

First of all, it’s important to know what a variant is. Viruses mutate—they are constantly changing. When they do, it’s called a new variant or strain. During the COVID-19 pandemic, variants of the virus (SARS-CoV-2) have been found in the U.S. and around the world.

New COVID strains are classified as variants being monitored, variants of interest, variants of concern, and variants of high consequence by the SARS-CoV-2 Interagency Group (SIG).

This committee was organized by the U.S. Department of Health and Human Services, and coordinates across the U.S. Centers for Disease Control and Prevention (CDC), National Institutes of Health (NIH), U.S. Food and Drug Administration (FDA), Biomedical Advanced Research and Development Authority (BARDA), and Department of Defense (DoD).

All COVID variants are being studied and monitored by federal agencies. The goal is to define the countermeasures that need to be taken, such as vaccination, therapeutics, and diagnostics, as new strains of each category emerge. The World Health Organization (WHO) also classifies variants of interest, and those classifications may vary from those in the U.S. The WHO has begun using the Greek alphabet to describe variants, to make it easier to discuss with nonscientific audiences.

Variants being monitored

The following are classified as variants being monitored. These new coronavirus variants don’t pose an imminent, serious risk to the U.S., but have a potential impact on approved treatments against severe disease:

B.1.1.7 (first detected in the United Kingdom)
B.1.351 (first detected in South Africa)
P.1 (first detected in Japan and Brazil)
B.1.427 and B.1.429 (first detected in California)
B.1.525 (first detected in the U.K. and Nigeria in December 2020)
B.1.526 (first detected in New York in November 2020)
B.1.617.1 (first detected in India in December 2020)
B.1.617.3 (first detected in India in October 2020)
P.2 (first detected in Brazil in April 2020)
B.1.621, B.1.621.1 (first detected in Colombia in January 2021)

Several of these variants began as variants of interest, and were downgraded to variants being monitored as scientists learned more.

Variants of interest

Variants of interest may potentially be less receptive to monoclonal antibody treatments and vaccines. There are currently no variants of interest being monitored in the U.S.

Variants of concern

The following are classified as variants of concern. Variants of concern may spread more easily, cause more severe disease (more hospitalizations or increased risk of deaths), lead to less generation of antibodies, have less efficacy in treatment or vaccines, or cause failures with diagnosis.

B.1.617.2 (first detected in India)
B.1.1.529 (first detected in South Africa)

These variants are more commonly known as the Delta variant and the Omicron variant, respectively.

Variants of high consequence

Variants of high consequence are associated with diagnostic failure, significantly reduced vaccine efficacy (or an unusually high number of COVID-19 cases in vaccinated people), inadequate response to treatment, and more severe illness and higher number of hospitalizations.

According to the U.S. Centers for Disease Control and Prevention (CDC), “a variant of high consequence would require notification to WHO under the International Health Regulations, reporting to CDC, an announcement of strategies to prevent or contain transmission, and recommendations to update treatments and vaccines.”

Currently, there are no coronavirus variants of high consequence.

How contagious are the COVID variants?

The U.K. and South African variants may be about 50% more contagious than the original strain common in the U.S.

The Delta variant (B.1.617.2) is estimated to be about 40% more transmissible than the U.K. variant. The Omicron variant (B.1.1.529) is the most contagious variant yet, quickly becoming the dominant strain in the U.S.

Scientists are studying all aspects of variants, including how they spread and the severity of disease they cause.

New COVID mutations mean that reinfections are possible in both vaccinated people and those who have already recovered from a previous coronavirus infection; however, these cases seem to be more mild than initial infections.

Do the current vaccines work against new COVID strains?

According to the World Health Organization (WHO), the currently approved COVID-19 vaccines (Moderna COVID-19 vaccine and Pfizer-BioNTech COVID-19 vaccine), as well as COVID-19 vaccines in development, are expected to provide “at least some protection against new virus variants” due to their ability to generate a broad response from the immune system. SARS-CoV-2 variants should not make vaccines completely ineffective.

However, if needed, due to lower efficacy against variants, scientists can adjust the vaccines to protect against these variants. This is the same calculus that researchers use to adjust the flu shot each year to give you the best protection possible from the circulating COVID-19 strains.

The WHO and other infectious disease experts are studying variants and their effects on vaccines. Vaccine changes or additional booster shots may be needed, but all of these things need to be studied in large clinical trials.

Also, new studies are continuously underway and reporting results. For example, one study concluded that “the findings suggest that current vaccines and therapeutic monoclonal antibodies will remain protective against the B.1.526 variants. The findings further support the value of wide-spread vaccination.”

How do I protect myself against COVID-19 variants?

First of all, don’t wait to get vaccinated or boosted. Despite the fact that additional boosters may be needed later, it’s essential to get vaccinated as soon as possible—even if the vaccines may be somewhat less effective against some variants. According to the World Health Organization, “We need to use the tools we have in hand even while we continue to improve those tools. We are all safe only if everyone is safe.”

Secondly, public health officials encourage everyone to continue preventive measures such as social distancing, masking, and handwashing. Check the CDC’s Quarantine and Isolation page to stay updated on physical distancing guidelines.

Finally, if you are planning to travel, check the CDC Travel Notice section. The CDC offers guidance to avoid travel to certain high transmission areas because even fully vaccinated travelers could get and spread COVID-19 variants. Ask your healthcare provider if you’re unsure whether you should travel.