Early Surge of COVID-19 Infections Driven by New Variant LB.1

A summertime surge of COVID-19 infections is occurring earlier than last year across much of the country, according to federal data, with the new variant LB.1 poised to become the dominant strain.

For the first time in months, the CBS News reports no states or territories experienced a slowdown in COVID-19 infections this past week. Indicators show the virus is spreading rapidly in western states, where infection levels began to rise this month.

Wastewater data from the western region, often an early indicator of rising cases, are nearing “high” infection risk levels as defined by the CDC. Nursing home COVID-19 cases in this region have also increased significantly. In HHS Region 9, which includes states from Arizona to Hawaii, 1.23% of emergency room visits are now COVID-19-related—the highest average since early February.

Historically, COVID-19 surges follow a spring lull, but the timing varies each year. Last year, nationwide increases began in late July, peaking in late August and early September, just as new vaccine shots were being prepared.

“For flu and RSV, we have years of data with consistent trends. For COVID, that’s not true at all,” noted Ruth Link-Gelles, head of the CDC’s COVID-19 vaccine effectiveness research, at a recent FDA meeting.

The emergence of LB.1 and KP.3 Variants

COVID-19 cases are rising alongside the emergence of two new variants, KP.3 and LB.1. As of the latest CDC projections, KP.3 constitutes roughly a third of cases nationwide, up from 25% two weeks ago, while LB.1 makes up 17.5% of cases. LB.1 is currently growing faster than KP.3 and may soon become the dominant variant.

Both variants, along with KP.2—a “FLiRT” variant that was dominant last month—descend from the JN.1 strain that caused a wave of cases last winter. as reported by Times Now.

“These new variants emerged relatively quickly. We had to react,” said Dr. Peter Marks of the FDA, during a webinar by Champions for Vaccine Education, Equity, and Progress. Marks defended the FDA’s recent decision to select KP.2 for Moderna and Pfizer’s updated shots this fall, reversing an earlier recommendation for JN.1. Although not based on “iron-clad evidence,” the decision aims to offer marginally better protection against current strains.

Since the FDA’s decision, the CDC has observed the rise of KP.3 and LB.1 over KP.2. It’s still unclear whether these new variants show increased severity. The CDC has not yet commented on this.

Early lab data from Japan, released as a preprint, suggest that one of LB.1’s mutations—S