Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.
Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

Variant Roundup

Variant Roundup
Updated Feb. 3, 2023
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Interpretive Summary for February 3, 2023

Variant Roundup

The virus that causes COVID-19 is constantly changing. We continue to see new lineages of the Omicron variant, such as XBB.1.5, emerge and spread in the United States. This week, we provide an update on the most common Omicron lineages currently circulating in the United States.

Covid-19 lineages flowchart
  • XBB.1.5 is a sublineage of the XBB lineage, which is a combination of two earlier Omicron lineages: BM.1.1 and BJ. As Nowcast projected, XBB.1.5 has risen to be the predominant Omicron lineage in the United States, accounting for an estimated 66.4% of all new cases. It is the only major lineage currently increasing in proportion in the country. Learn more about XBB.1.5 in A Closer Look below.
  • BQ.1 and BQ.1.1 are sublineages of the BA.5 lineage of the Omicron variant. BA.5 and its sublineages are continuing to decrease in proportion nationally. According to Nowcast projections, BQ.1 and BQ.1.1 together represent about 27% of all weekly cases.
  • CH.1.1 is a sublineage of BA.2.75. CH.1.1 is predicted to make up an estimated 1.6% of circulating viruses nationally, according to Nowcast projections. These percentages represent a steady decline.

CDC will continue to watch the Omicron variant and its lineages closely and monitor how well vaccines and other treatments perform. On January 26, the U.S. Food and Drug Administration announcedExternal that Evusheld is no longer authorized for emergency use in the United States. Data show that Evusheld is unlikely to be active against certain SARS-CoV-2 lineages, including the main lineages circulating now. It is important that people who are moderately to severely immunocompromised exercise caution and recognize the need for additional prevention measures, as well as other treatment options.

COVID-19 vaccines are an effective way to protect yourself against severe COVID-19. The updated booster vaccine has been reformulated to better protect against the most recently circulating variants. It can also help restore protection that has waned since previous vaccination. Unfortunately, uptake is at an all-time low since vaccines were rolled out in early 2021—only about one in six people in the United States (15.7%) have received an updated COVID-19 booster. CDC recommends that everyone ages 5 years and older get an updated booster if it has been at least two months since their last COVID-19 dose (either primary series or original booster). Children ages 6 months through 5 years who completed the Moderna COVID-19 vaccine primary series can also get an updated COVID-19 booster. Find a vaccine.

Note to Readers: To help people visualize how variants emerge, disappear, and persist, CDC’s COVID Data Tracker added a dendrogram (tree diagram) to the Summary of Variant Surveillance and Variant Proportions pages. Dendrograms are like variant family trees, showing the genetic relationships between the lineages displayed on the COVID Data Tracker genomic surveillance pages.

COVID-19 Community Levels*

As of February 2, 2023, there are 130 (4%) counties, districts, or territories with a high COVID-19 Community Level, 818 (25.4%) with a medium Community Level, and 2,269 (70.5%) with a low Community Level. Compared with last week, the number of counties, districts, or territories in the high level increased by 0.4%, in the medium level decreased by 1.1%, and in the low level increased by 0.8%. Overall, 47 out of 52 jurisdictions** had high- or medium-level counties this week. Arizona, District of Columbia, Hawaii, Nevada, and Utah are the only jurisdictions to have all counties at low Community Levels.

To check your COVID-19 Community Level, visit COVID Data Tracker. To learn which prevention measures are recommended based on your COVID-19 Community Level, visit COVID-19 Community Level and COVID-19 Prevention.

*CDC recommends use of COVID-19 Community Levels to determine the impact of COVID-19 on communities and to take action. CDC also provides Community Transition Levels to describe the amount of COVID-19 spread within each county. Healthcare facilities use Community Transmission Levels to determine infection control interventions.

**Includes the 50 states, the District of Columbia, and Puerto Rico.

U.S. COVID-19 Community Levels by County

A map of the United States showing COVID-19 Community Levels green is low, yellow is medium, orange is high, grey is no data

Reported Cases

As of February 1, 2023, the current 7-day average of weekly new cases (40,130) decreased 6.7% compared with the previous 7-day average (43,035). A total of 102,447,438 COVID-19 cases have been reported in the United States as of February 1, 2023.

Total Cases Reported

Current 7-Day Average*

Previous 7-Day Average

Change in 7-Day Average since Previous Period

*Historical cases are excluded from weekly new cases and 7-day average calculations until they are incorporated into the dataset for the applicable date. Of 25,904 historical cases reported retroactively, 4,507 were reported in the current week and none in the prior week.

Weekly Trends in COVID-19 Cases in the United States Reported to CDC

Weekly trends in COVID-19 cases in the United States reported to CDC

COVID-19 Variants

CDC Nowcast projections* for the week ending February 4, 2023, estimate the proportion of these lineages designated as Omicron with estimates above 1%: XBB.1.5, BQ.1.1, BQ.1, XBB, CH.1.1, and BN.1.

XBB.1.5 is projected to be at approximately 66.4% (95% PI 59.8-72.5%). The second most prevalent lineage is BQ.1.1, projected to be at approximately 19.9% (95% PI 16.2-24.1%).

BQ.1, XBB, CH.1.1, and BN.1 are all projected to be between 1% and 8% of circulating lineages.

XBB.1.5 is growing in proportion in all HHS regions. All other virus lineages are predicted to have very slow or no growth in proportion.

See COVID Data Tracker for the proportions of all relevant lineages currently circulating.

*CDC uses Nowcast projections to predict current variant proportions circulating in the United States. The median time from specimen collection to sequence data reporting is about 3 weeks. As a result, weighted estimates for the most recent few weeks may be unstable or unavailable. View Nowcast estimates on CDC’s COVID Data Tracker website on the Variant Proportions page.  

Proportions of COVID-19 variants in the United States, January 29, 2023 through February 4, 2023


As of February 1, 2023, 669.6 million vaccine doses have been administered in the United States. Overall, about 229.7 million people, or 69.2% of the total U.S. population, have completed a primary series.* More than 42.1 million people, or 20.1% of the eligible U.S. population ages 5 years and older, have received an updated booster dose.

Vaccine Doses Administered

Updated Booster Doses Administered**

People who have completed a primary series* (69.2% of the U.S. population)

People who have received an updated booster (20.1% of the eligible U.S. population)***

Percentage point change from last week

Percentage point change from last week

*Represents the number of people who have received the second dose in a two-dose COVID-19 vaccine series (such as the Pfizer-BioNTech, Moderna, or Novavax vaccines) or one dose of the single-shot Johnson & Johnson’s Janssen vaccine.

**Includes all updated booster doses administered regardless of recipient eligibility.

***Includes only recipients who are eligible to receive an updated booster. Beginning January 20, 2023, the “People who have received an updated booster” count was revised from including all people who received an updated booster to only eligible people who received an updated booster.

Daily Change in the Total Number of Administered COVID-19 Vaccine Doses Reported to CDC by the Date of Administration, United States

red line

7-Day moving average

Daily Change in the Total Number of Administered COVID-19 Vaccine Doses Reported to CDC by the Date of Administration, United States

COVID-19 Updated Booster Dose Administration, United States

COVID-19 updated (bivalent) booster dose administration in the United States booster legend


New Hospital Admissions

The current 7-day daily average for January 25–31, 2023, was 3,919. This is an 8.4% decrease from the prior 7-day average (4,279) from January 18–24, 2023.

Total New Admissions

Current 7-Day Average

Prior 7-Day Average

Change in 7-Day Average

The start of consistent reporting of hospital admissions data was August 1, 2020.

Daily Trends in Number of New COVID-19 Hospital Admissions in the United States

Daily trends in number of new COVID-19 hospital admissions in the United States

New admissions are pulled from a 10 am EDT snapshot of the HHS Unified Hospital Data – Analytic Dataset. Due to potential reporting delays, data from the most recent 7 days, as noted in the figure above with the grey bar, should be interpreted with caution. Small shifts in historic data may also occur due to changes in the Centers for Medicare & Medicaid Services (CMS) Provider of Services file, which is used to identify the cohort of included hospitals.

RESP-NET: COVID-19 Associated Hospitalization Rates among Adults Ages 65 Years and Older

CDC’s Respiratory Virus Hospitalization Surveillance Network (RESP-NET) shows that overall weekly rates of COVID-19-associated hospitalizations appear to be beginning to decrease from a peak in December 2022. However, overall COVID-19-associated hospitalization rates remain elevated, at 8.2 per 100,000 population for the week ending January 14, 2023.

Weekly Rates of Respiratory Virus-Associated Hospitalizations among Adults Ages 65 Years and Older

RESP-NET: COVID-19 Associated Hospitalization Rates among Adults Ages 65 Years and Older

The dashed lines for the current season indicate potential reporting delays and interpretation of trends should exclude data from recent weeks. Coronavirus Disease 2019 (COVID-19)-Associate­­d Hospitalization Surveillance Network (COVID-NET), a RESP-NET platform, is an additional source for hospitalization data collected through a network of more than 250 acute-care hospitals in 13 states (representing ~10% of the U.S. population). Detailed data on patient demographics, including race and ethnicity, underlying medical conditions, medical interventions, and clinical outcomes, are collected using a standardized case reporting form.



The current 7-day average of new deaths (493) decreased 9.0% compared with the previous 7-day average (542). As of February 1, 2023, a total of 1,106,824 COVID-19 deaths have been reported in the United States.

Total Deaths Reported

Current 7-Day Average*

Prior 7-Day Average

Change in 7-Day Average Since Prior Period

*Historical deaths are excluded from the weekly new deaths and 7-day average calculations until they are incorporated into the dataset by their applicable date. Of 3,838 historical deaths reported retroactively, none were reported in the current week and none were reported in the prior week.

Weekly Trends in Number of COVID-19 Deaths in the United States Reported to CDC

Weekly trends in number of COVID-19-associated deaths in the United States reported to CDC More Death Data


The percentage of COVID-19 NAATs (nucleic acid amplification tests)* that are positive is increasing in comparison to the previous week. The 7-day average of percent positivity from NAATs is now 11.0%. The 7-day average number of tests reported for January 20–26, 2023, was 273,284, down 13.1% from 314,594 for the prior 7 days.

Total Tests Reported

7-Day Average Tests Reported

7-Day Average % Positivity

Previous 7-Day Average % Positivity

Percentage point change in 7-Day Average % Positivity since Prior Week

*Test for SARS-CoV-2, the virus that causes COVID-19

COVID-19 NAAT Laboratory Test 7-day Percent Positivity by State/Territory

US map showing COVID-19 NAAT Laboratory Test 7-day Percent Positivity.

Wastewater Surveillance

COVID Data Tracker’s Wastewater Surveillance tab tracks levels, changes, and detections of SARS-CoV-2* viral RNA in wastewater at over 1,100 testing sites across the country.

Currently, about 62% of sites across the country are reporting moderate to high SARS-CoV-2 levels in wastewater. About 28% of sites reporting wastewater data are currently seeing some of the highest levels for those sites since December 1, 2021. About 45% of sites are experiencing a decrease in SARS-CoV-2 levels, and about 44% are reporting an increase.

For more information on how to use wastewater data, visit CDC’s wastewater surveillance website.

*The virus that causes COVID-19

SARS-CoV-2 Levels in Wastewater by Site

SARS-CoV-2 levels in wastewater by site white dot new site, blue dot 0% to 19%, light blue dot 20% to 39%, lightest blue dot 40% to 59%, orange dot 60% to 79%, red dot 80% to 100%

0% denotes that levels are the lowest they have been at the site; 100% denotes that levels are the highest they have been at the site.

More Wastewater Data
A Closer Look

Learn More about XBB.1.5

XBB.1.5, a lineage of the Omicron variant, has recently become the predominant lineage circulating in the United States, with a projected prevalence of 66.4% for the week ending February 4, 2022. It was first detected in the United States in October 2022. XBB.1.5 is the only major lineage currently increasing in proportion across the country, and it is expected to continue increasing in all U.S. regions. It is most prevalent in the Northeastern states, where the proportions are estimated to be greater than 90%. XBB.1.5 is less common in other countries but has been detected in Europe, Asia, South America, and Africa.

XBB.1.5 became the dominant lineage fairly quickly. It has two additional spike substitutions (G252V and S486P), which may contribute to its apparent increased transmissibility. The severity of XBB.1.5 has not been fully assessed, but there is no indication right now that it causes more serious illness than other Omicron lineages.

Preliminary data from CDC and other researchers suggest that updated booster vaccine protection is similar against XBB.1.5 and other recent Omicron lineages. A recent CDC study shows that the updated COVID-19 boosters add protection against illness with Omicron XBB/XBB.1.5-related variants for at least the first three months after vaccination.

Antiviral treatments, such as Paxlovid and Veklury (remdesivir), are expected to be effective against XBB.1.5 and other Omicron lineages. But laboratory data has shown that pre-exposure drug Evusheld is not effective against the lineages (including XBB.1.5) that are currently causing more than 90% of the cases in the United States. As a result, on January 26, 2023, the U.S. Food and Drug Administration announcedExternal that Evusheld is no longer authorized for use in the United States until further notice.

CDC will continue to watch XBB.1.5 and monitor how well vaccines and other treatments perform against this new variant. It is likely that XBB.1.5 will continue to spread. Those who are up to date on their COVID-19 vaccinations have the most protection to fight off an infection caused by XBB.1.5. Most people will have minor or even potentially no symptoms and will not need to go to the hospital. However, people who are at higher risk for severe disease should continue to take precautions to protect themselves. Anyone who has symptoms or an exposure to COVID-19 should get tested. If they test positive, they should talk to their doctor or healthcare provider about treatments that may be right for them. This assessment could change as more data are available.