Pirola, or BA.2.86, has emerged as the third most prevalent COVID-19 strain in the U.S. Recent data from the Centers for Disease Control and Prevention (CDC) indicates a significant increase in Pirola cases, raising questions about vaccine efficacy (1).

Exploring Pirola’s Surge

Pirola has rapidly gained prominence, constituting 8.8% of COVID-19 cases as of November 25, 2023. This marks a substantial surge compared to the previous two-week period, highlighting the dynamic nature of COVID-19 variants. The Northeastern region, particularly, is experiencing a higher prevalence, making Pirola the second most common variant in the area after HV.1.

Pirola’s Classification and Variants

Recently designated as a “variant of interest” by the World Health Organization (WHO), Pirola belongs to the Omicron family. It originated as a highly mutated offshoot of its parent variant, BA.2.86, which dominated in 2022. Notably, one of Pirola’s mutations, JN.1, has spread rapidly globally, raising concerns about its impact on vaccine protection.

Vaccine Defense Against Pirola

While concerns persist regarding the efficacy of monovalent vaccines against Pirola, leading pharmaceutical companies, including Pfizer-BioNTech and Novavax, assert that their latest vaccines provide protection. Moderna’s September clinical trial reported an 8.7-fold increase in protection against Pirola. The CDC also emphasizes that the “public health risk posed by this variant is low,” and updated vaccines are anticipated to enhance defense.

Controversies Surrounding Vaccine Efficacy

Despite assurances from drugmakers and health authorities, some experts express reservations about the effectiveness of current vaccines against Pirola. A bioRxiv study suggests that the newer vaccines may inadvertently contribute to the spread of Pirola viruses, raising important considerations for ongoing research and vaccine development.

Understanding Pirola’s Impact

It remains unknown whether Pirola induces different symptoms compared to other variants. As part of the Omicron family, Pirola’s complexity poses challenges in predicting its behavior and implications for public health. JN.1, a significant mutation within Pirola, has been detected in multiple countries, emphasizing the need for a comprehensive understanding of its global impact.

Alarming Trends in Hospitalizations and Deaths

As the U.S. witnesses a surge in Pirola cases, the week of November 18 saw a concerning increase in hospitalizations, reaching 18,119, up almost 9% from the previous week. Deaths also rose by 8.3%, totaling 506. These statistics underscore the urgency of addressing the evolving landscape of COVID-19 variants and their potential consequences.

Dominance of HV.1 and Eris Variant

Amidst the Pirola surge, HV.1 remains the most prevalent Covid strain in the U.S., constituting 31.7% of cases as of November 25. This strain surpassed EG.5, or the “Eris” variant, in late October. Both HV.1 and Eris belong to the XBB lineage, ensuring protection from the new COVID-19 vaccines.