The emergence of new variants of SARS-CoV-2, the virus responsible for COVID-19, remains a significant aspect of the ongoing pandemic. One such variant, BA.2.86, has drawn attention since its initial detection. Understanding its characteristics, from its genetic makeup to its potential impact on health, is important for informed public health responses and individual precautions.
Understanding BA.2.86
BA.2.86 is an Omicron sub-lineage, first identified in a sample on July 24, 2023. It gained attention due to over 30 mutations on its spike protein compared to BA.2. This significant genetic divergence prompted the World Health Organization (WHO) to designate it as a “variant under monitoring” on August 17, 2023. The variant was also informally nicknamed “Pirola” by media outlets, a name created by combining the Greek letters pi and rho.
The number of mutations in BA.2.86 is comparable to the shift seen between the original Omicron variant and the earlier Wuhan-Hu-1 reference strain. Spike protein mutations in BA.2.86 include an ins_16MPLF insertion and a Δ69-70 deletion. Other notable mutations include R403K, which enhances ACE2 receptor affinity, and L452W and A484K mutations. Despite these changes, its descendant, JN.1, became the dominant lineage in late 2023 and early 2024.
Symptoms and Clinical Presentation
Symptoms associated with BA.2.86 are similar to those experienced with earlier Omicron variants and other strains of COVID-19. Common symptoms include headache, body aches, cough, fever, generalized muscle pain, and severe fatigue. Sore throat has also become a more prevalent symptom with Omicron subvariants, including BA.2.86, while the loss of taste and smell, a hallmark of earlier COVID-19 variants, is less common.
While BA.2.86 has spread rapidly, there have been no reported deaths directly attributed to it, suggesting it may not cause more severe illness than its predecessors. Symptoms typically appear between 2 to 14 days after exposure to the virus, ranging from mild to severe. The severity of symptoms often depends more on an individual’s immunity rather than the specific variant causing the infection.
Transmissibility and Public Health Implications
BA.2.86 has demonstrated a degree of transmissibility, with detections across multiple continents indicating international spread. It has spread swiftly and been reported in numerous countries, including the United Kingdom, United States, and various European nations. The detection of cases without known links to other infected individuals or recent travel history suggests community transmission is occurring.
Despite its ability to spread, BA.2.86 did not appear to be rapidly increasing or driving significant surges in infections or hospitalizations in the United States as of late 2023. The World Health Organization and the CDC have assessed the public health risk posed by BA.2.86 as low compared to other circulating variants. However, the emergence of variants with numerous mutations, like BA.2.86, highlights the need for ongoing genomic surveillance to detect and manage new variants.
Current Protection and Prevention
Existing COVID-19 vaccines and updated booster shots are expected to offer protection against BA.2.86, particularly in reducing severe disease and hospitalizations. Laboratory studies suggest that bivalent mRNA vaccine-induced antibodies can neutralize BA.2.86, explaining why it did not cause a widespread surge as initially feared. Updated monovalent XBB.1.5 vaccines also provided protection against symptomatic SARS-CoV-2 infection caused by JN.1 and other XBB-related lineages, including BA.2.86.
While BA.2.86 may be capable of causing infection in individuals with prior COVID-19 or vaccination, most people likely retain some protection against severe outcomes. Standard COVID-19 tests, including molecular and antigen-based tests, are expected to remain effective in detecting BA.2.86. General preventative measures, such as maintaining good ventilation, wearing masks in crowded indoor settings, and staying home when feeling unwell, continue to be important strategies for reducing transmission.