Risk Assessment Summary for SARS CoV-2 Sublineage BA.2.86

The Centers for Disease Control and Prevention (CDC) has detected a new SARS-CoV-2 variant, BA.2.86. Ongoing monitoring and research are being conducted to assess its potential public health impact.

Background

All viruses, including SARS-CoV-2, evolve over time. When genetic changes occur, these new forms are referred to as variants. Mutations can influence how easily a virus spreads, its response to treatment, and the severity of illness it causes. Recently, BA.2.86 was identified in Denmark and Israel, with at least two cases confirmed in the United States. This variant stands out due to significant genetic differences compared to earlier SARS-CoV-2 versions.

Current Risk Assessment

Existing COVID-19 tests and treatments appear to remain effective against BA.2.86. However, this variant may have an increased ability to infect individuals who have previously contracted COVID-19 or received vaccinations. Researchers are evaluating the effectiveness of upcoming updated COVID-19 vaccines, with current assessments indicating they will help reduce the risk of severe illness and hospitalization. As of now, there is no evidence suggesting that BA.2.86 causes more severe disease than previous variants. Further studies will provide additional insights, and updates will be shared as new information becomes available.

Recommended Prevention Measures

If approved by the FDA and recommended by the CDC, updated vaccines could be available at pharmacies and healthcare facilities by mid-September.

Until more is known, the following steps are advised to reduce risk:

• Stay up to date on COVID-19 vaccinations
• Avoid contact with others when sick
• Get tested if symptoms appear
• Seek treatment if at high risk for severe illness
• Use a high-quality, well-fitted mask if wearing one is preferred
• Ensure good ventilation in indoor spaces
• Wash hands frequently

Scientific Findings on BA.2.86 (As of August 23, 2023)

Human Cases

As of August 23, 2023, a total of nine BA.2.86 sequences have been identified worldwide:

• Denmark (3)
• South Africa (2)
• Israel (1)
• United States (2)
• United Kingdom (1)

One of the U.S. cases was identified through the CDC’s Traveler-Based Genomic Surveillance program. The presence of the variant in multiple countries suggests global transmission. However, genomic sequencing of SARS-CoV-2 has significantly decreased compared to previous years, meaning additional variants could be circulating undetected.

Current hospitalization increases in the U.S. are not linked to BA.2.86. This assessment may change as more data becomes available.

Severity

It is too early to determine whether BA.2.86 causes more severe illness than earlier variants. CDC is monitoring hospitalization trends to detect potential signs of increased severity. At this time, areas where the variant has been detected have not experienced unusual spikes in cases or hospitalizations compared to nearby locations. However, more data is needed to fully understand its impact.

Transmission

With only a small number of cases identified, the transmissibility of BA.2.86 remains uncertain. Its presence in multiple countries suggests some level of spread, which is notable since similar highly mutated lineages have not been widely transmitted.

Detection in Wastewater

A U.S. wastewater sample collected through the National Wastewater Surveillance System (NWSS) has indicated the presence of BA.2.86. Further analysis is ongoing, and wastewater monitoring remains an essential tool for detecting the spread of variants.

Genetic Characteristics of BA.2.86

BA.2.86 has been designated as a new SARS-CoV-2 variant due to the significant number of mutations observed.

• It has over 30 amino acid differences compared to BA.2, which was the dominant Omicron lineage in early 2022.
• It also has more than 35 amino acid changes compared to XBB.1.5, the most prevalent variant during most of 2023.
• The level of genetic variation is comparable to differences seen between the original Omicron variant (BA.1) and previous variants like Delta (B.1.617.2).

Potential Immune Impact

Due to its high number of mutations, BA.2.86 may be better at evading immunity from vaccinations and prior infections than recent variants. Some initial genetic analyses suggest that the difference between BA.2.86 and other circulating variants is as large as or greater than that between BA.2 and XBB.1.5, which emerged almost a year apart.

However, virus samples are still limited, and more research is needed to determine the real-world impact on immunity. Most of the U.S. population has antibodies from vaccination, previous infection, or both, which should provide some level of protection against severe illness from this variant. This remains an active area of investigation.

Effectiveness of Treatments and Tests

Therapeutics

The mutation profile of BA.2.86 suggests that current antiviral treatments, including Paxlovid, Veklury, and Lagevrio, remain effective. Research is ongoing, and further data will be analyzed to assess the impact of this variant on available treatments.

Diagnostics

Current molecular and antigen-based COVID-19 tests are expected to reliably detect BA.2.86, based on its mutation profile.

Clarification on BA.2.86 Risk Assessment (September 20, 2023)

An earlier CDC risk assessment (August 23, 2023) included the statement: "BA.2.86 may be more capable of causing infection in people who have previously had COVID-19 or who have received COVID-19 vaccines." Some misinterpreted this to suggest that vaccines were ineffective. The intent was to highlight that BA.2.86 could have an increased ability to infect individuals compared to other circulating variants, not that vaccination provides no protection.

Laboratory data now indicate that existing immunity from previous infections and COVID-19 vaccines provides similar protection against BA.2.86 as it does against other variants. Updated vaccines are expected to maintain effectiveness in preventing severe illness.

Respiratory Virus Guidance

Each year, respiratory viruses contribute to millions of illnesses, hospitalizations, and deaths in the United States. In addition to the virus responsible for COVID-19, other common respiratory viruses include influenza (flu) and respiratory syncytial virus (RSV). However, various preventative measures can help reduce health risks associated with these infections.

CDC’s Respiratory Virus Guidance

The Centers for Disease Control and Prevention (CDC) provides guidance aimed at lowering the risk of illness from respiratory viruses, including COVID-19, flu, and RSV. The recommendations focus on several key prevention strategies:

• Immunizations
• Hygiene practices
• Improving air quality
• Reducing transmission when sick
• Use of masks
• Physical distancing
• Testing for infections

Special Considerations for High-Risk Groups

Some individuals face a higher risk of severe illness from respiratory viruses. These groups include:

• Older adults
• Young children
• Individuals with weakened immune systems
• People with disabilities
• Pregnant individuals

Taking extra precautions is especially important for those who fall into these categories.

Using Treatment as a Prevention Strategy

Early treatment is a key strategy to reduce the severity of respiratory virus infections. Seeking medical care promptly for testing and treatment can help individuals at risk for severe illness. Treatment for flu and COVID-19 can:

• Lessen symptom severity
• Shorten the duration of illness
• Reduce complications that may lead to hospitalization

Steps to Take for Effective Treatment

To ensure access to appropriate treatment, individuals should:

• Learn about available treatment options for flu and COVID-19 before getting sick.
• Consult a healthcare provider about preparing for potential illness.
• Discuss antiviral treatments with friends and family, emphasizing their role in preventing severe outcomes.
• Follow prescribed treatment plans exactly as directed.
• Ask a healthcare provider any questions regarding available treatments.

Vaccination Trends

The National Immunization Survey (NIS) estimates presented are based on survey responses rather than official vaccine records or administration data.

During the COVID-19 Public Health Emergency (PHE), the CDC monitored nearly all administered COVID-19 vaccines. However, with the end of the PHE, the availability of complete vaccine administration data has been reduced.

As a result, survey data now serve as the primary method for tracking COVID-19, influenza, and RSV vaccinations among adults.

CDC Vaccination Recommendations

The CDC advises that everyone aged 6 months and older should stay up to date with COVID-19 vaccines and receive a seasonal flu shot.

For individuals 60 years of age and older, consulting a healthcare provider to determine whether the RSV vaccine is appropriate is recommended.

Additionally, the CDC recommends nirsevimab, a monoclonal antibody, for:

• Infants younger than 8 months who are born during or entering their first RSV season.
• Certain older infants are at higher risk for severe RSV infection.