LP.8.1 fall booster
Limited eligibility? Keeping pace with emerging NB.1.8.1?
COVID and flu infections are below the season’s start, but deaths persist. After 5 weeks with all regions showing low COVID virus levels in wastewater, the Midwest and Northeast are now very low (CDC). Flu virus in wastewater is very low for the 4th week nationally (Table 1 based on CDC data).
Although the COVID mortality rate at 0.4% of all causes of death continues to drop, it’s the 8th week with more people dying of COVID than flu, 2455 v. 1463 in the 2-month stretch, which averages 307 a week. For flu, the 0.15% rate sounds low, but it's still above the season’s start in November. There are also at least 231 pediatric flu deaths, the highest since the swine flu pandemic in 2009.
Measles continues to creep up. CDC’s confirmed count on Thursday was 1046. Iowa became the 31st state by adding 1 case of an unvaccinated child on Friday, their first since 2019 (IA HHS). Texas reported 750 cases on Friday with 22 of them outside of West Texas (TX DSHS). The original outbreak appears to be waning with less than 10 cases still infectious and only 7 of the 34 counties previously involved still active.
Vaccines
• FDA endorses its VRBPAC advisors’ recommendation to stick with the JN.1 branch of Omicron as targets for this fall’s jabs (Update May 22). FDA instructed manufacturers to proceed accordingly with a preference for LP.8.1, the dominant virus in the US accounting for 70% of new infections two weekends ago (FDA, CDC).
However, it’s still unclear if and how the agency’s new policy for COVID vaccines will be applied to the proposed fall shots (Update May 20).
✓ Does a new LP.8.1 vaccine require clinical trials to demonstrate safety and efficacy?
✓ Will the current JN.1 and KP.2 formulations or an LP.8.1 update be unavailable for healthy people under 65?
• Emerging virus from Asia Even as VRBPAC deliberated to pick a target for the fall, a new virus had emerged to cause surges in Asia and had already come ashore in the US. NB.1.8.1 is also in the JN.1 line and has been spreading in China, Taiwan, and Hong Kong (CBS). There’s a manuscript from a Chinese lab suggesting the virus binds cells better and could be more transmissible (bioRxiv). Taiwan had more than 19,000 outpatient visits for COVID in a week (Taiwan CDC). More than 90% of cases in the surge didn’t have the JN.1 jab. In Hong Kong the last 4 weeks, there have been 81 severe cases with a 37% mortality rate (Hong Kong DH). Only 1 case had a JN.1 booster in the past 6 months.
The US cases have been detected by CDC monitoring major airports here for arrivals from more than 25 countries. The Traveler-Based Genomic Surveillance Program tests swabs from passengers to identify the virus variants. NB.1.8.1 cases arrived as early as March in CA, NY, VA, and WA from China, Japan, South Korea, Taiwan, Thailand, Vietnam, France, Netherlands, and Spain (GISAID). Cases have also popped up in HI, OH, and RI that were not from airport arrivals.
• Current KP.2 and new LP.8.1 vaccines cover LP.8.1 and NB.1.8.1 Moderna presented data at VRBPAC from a Phase 3/4 clinical trial showing this season’s formulation boosts neutralizing antibodies against LP.8.1 14-fold, as well as it does with other JN.1 viruses (Table 2 derived from Moderna data).
Moderna also conducted studies with mice that suggest its LP.8.1 vaccine candidate could do well in producing neutralizing antibodies against LP.8.1 and NB.1.8.1 for people (Table 3 derived from Moderna data). The results also suggest staying with the KP.2 vaccine in 2025-2026 to protect against an NB.1.8.1 surge remains a good option.
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