United States: Amidst a period of relative tranquility during spring, California and eleven other states are now witnessing a resurgence in COVID-19 metrics, with notable increases in various indicators.
Recent statistics from the Centers for Disease Control and Prevention indicate a consistent rise in the proportion of emergency department cases diagnosed with COVID-19 in California over the last month. Nevertheless, this figure remains notably lower than the peak observed last summer.
The latest data from The Chronicle’s COVID-19 wastewater surveillance tracker confirms a significant escalation in virus levels across the Bay Area, with upticks recorded in ten out of twelve monitored sites. Additionally, California’s current coronavirus test positivity rate has climbed to 3.2% from April’s 2.1%, although it still falls below the 5% threshold deemed indicative of concerning community spread, according to the San Francisco Chronicle.
The emergence of a new cluster of coronavirus variants known as FLiRT is potentially contributing to this recent upswing.
Dr. John Swartzberg, a clinical professor emeritus specializing in infectious diseases and vaccinology at UC Berkeley, has highlighted two primary factors fuelling this resurgence: the heightened transmissibility of the FLiRT variants and the diminishing background immunity among individuals.
“These two factors combined will likely precipitate another surge in infections,” he emphasized. “This trend is evident not only in California but also on a national and international scale.”
According to the CDC’s modeling, an increase in coronavirus infections is not limited to California but is also observed in several other states and regions, including Alaska, Arizona, Florida, Georgia, Hawaii, Minnesota, Nevada, New Jersey, Oregon, Texas, Washington, and Washington DC.
Moreover, this week has seen the United Kingdom, Singapore, and various other global regions report significant spikes in COVID-19 infections, as reported by San Francisco Chronicle.
The FLiRT variants, specifically KP.2 and KP.1.1, have now outpaced their parent strain JN.1 to become the dominant omicron offshoots in the United States, accounting for over one-third of infections nationwide, as per the latest CDC data.
This surge in cases signifies the beginning of an anticipated rise from the historically low levels of COVID-19 hospitalizations and fatalities in California, including a day in April with no reported deaths.
While acknowledging the increase in cases, Swartzberg emphasized the importance of recognizing that this rise is occurring from a comparatively low baseline.
“We are still in a favorable position,” he asserted.
The mutations observed in the FLiRT variants may enhance their infectivity as frontline immunity acquired from prior illness or vaccination wanes over time. However, the CDC has stated that there is no evidence suggesting that KP.2 and KP.1.1 cause more severe illness.
Andy Pekosz, a professor specializing in molecular microbiology and immunology at Johns Hopkins, recently echoed this sentiment.
“In terms of symptoms, there is no discernible difference with these variants,” he stated in a Q&A session regarding the FLiRT variants. “After years of vaccinations and infections, a significant portion of the population is better equipped to combat an infection without significant concern for severe illness.”
While the CDC discontinued its requirement for states to report COVID-19 hospital admissions last month, thereby phasing out one of the most reliable metrics for tracking the pandemic’s trajectory over the past four years, the agency will continue to rely on wastewater surveillance, test positivity rates, and fatalities to monitor the virus as fall approaches, San Francisco Chronicle reported.
“We are no longer hoping for the disappearance of this virus. Instead, we are aiming for it to adopt a seasonal pattern akin to influenza. However, we have not reached that stage yet,” Swartzberg remarked. “The trajectory in the fall will depend on the efficacy of the vaccine chosen to match the prevailing variants at that time.”
FDA advisers are scheduled to convene in early June to determine the formulation of the upcoming fall vaccine, which is expected to target JN.1 and its derivatives, including the FLiRT variants.
Encouraging uptake of the vaccine will pose a significant challenge. Last fall, only 22% of adults received the updated vaccine designed to target the omicron subvariant XBB.1.5, which dominated in early 2023, leaving a growing number of individuals susceptible to infection.
“While these surges are diminishing in magnitude, they continue to disproportionately affect our vulnerable populations: the elderly, immunocompromised individuals, and those with underlying medical conditions,” Pekosz cautioned. “Everyone can contribute to protecting these high-risk populations when new variants lead to an uptick in cases.”