Title: Preliminary Studies Suggest Immunity Levels High Against Omicron Subvariant BA.2.86 Despite Surge in COVID-19 Cases
Subtitle: Hospitalizations, Deaths, and Test Positivity Rates Rising Amidst Concerns Over Waning Surveillance and Testing
Date: [INSERT DATE]
In recent days, preliminary studies on the highly evolved omicron subvariant BA.2.86 have provided some relief, suggesting that it may not be as immune evasive or dangerous as initially feared. However, this positive news is overshadowed by the latest COVID-19 data, which shows a surge in hospitalizations, emergency department visits, and deaths. The current wave of infections is primarily driven by circulating omicron subvariants such as EG.5, FL.1.5.1, and XBB.1.16.6, with EG.5 showing an upward trend in dominance.
According to the Centers for Disease Control and Prevention (CDC), hospitalizations in the US have increased by nearly 16 percent in the past week, while deaths have risen by almost 18 percent. Test positivity rates also indicate a steep incline, painting a concerning picture of the current situation. It is worth noting that these numbers, although relatively low compared to previous waves, might be underestimated due to plummeting surveillance systems and testing capabilities. The timing of this surge, preceding the availability of fall booster doses, raises concerns for the most vulnerable populations.
The World Health Organization (WHO) has expressed worry about the low vaccination rates among at-risk individuals. WHO Director-General Tedros Adhanom Ghebreyesus emphasized the importance of not delaying the administration of additional vaccine doses if recommended. The US Food and Drug Administration (FDA) is expected to approve fall booster doses as early as this Friday, with the CDC likely to follow suit promptly. The fall boosters, specifically designed to target XBB.1.5, have shown effectiveness against the leading variants, including EG.5 and FL.1.5.1. Additionally, Moderna announced that its booster is also effective against BA.2.86, generating a substantial increase in neutralizing antibodies in preliminary clinical trial data.
The future implications of BA.2.86 remain unclear. While initial concerns were raised due to its numerous mutations and rapid international spread, the mutated omicron subvariant has remained relatively uncommon. As of now, researchers from only 12 countries have reported a total of 64 BA.2.86 genome sequences out of the thousands of SARS-CoV-2 sequences submitted weekly. In contrast, approximately 30 percent of the recently submitted sequences are EG.5, according to Maria Van Kerkhove, WHO’s COVID-19 technical lead.
Recent pre-print studies shed light on why BA.2.86 has not become more prevalent. Chinese researchers found that BA.2.86 was less efficient at infecting cells in lab settings compared to other circulating omicron subvariants. They concluded that BA.2.86 may have traded infectivity for higher immune evasion during long-term host-viral evolution. Nevertheless, close monitoring of additional mutations that could enhance BA.2.86’s infectivity is warranted.
A Swedish study examined how serum from blood donors neutralized BA.2.86 relative to other variants. Although there were dips in neutralizing levels against BA.2.86, they were not as severe as initially feared. The study found that neutralizing antibody levels against BA.2.86, even during the circulation of XBB variants, remained relatively strong compared to levels seen against XBB.1.5. Similarly, a US-based study observed that neutralizing antibody responses against BA.2.86 were significantly lower than those against BA.2 but still comparable or slightly higher than those against other circulating omicron subvariants.
In light of these findings, researchers caution that although BA.2.86 may not pose an immediate threat, it could continue to evolve, especially given the current limitations in COVID-19 monitoring systems. The importance of maintaining robust genomic surveillance infrastructure remains paramount.
As the FDA prepares to approve fall booster doses, monitoring the evolving COVID-19 landscape is crucial. While the initial studies offer some reassurance, experts emphasize the need for continued vigilance and adherence to public health measures to combat the pandemic effectively.