Posted on 08/05/2025 3:00:34 PM PDT by nickcarraway
JN.1 mRNA boosters in Europe showed high protection against hospitalization and death
Key Takeaways:
-In Danes over age 65, the vaccine effectiveness of the JN.1-based mRNA boosters reached 70-85% against COVID-related hospitalization and 76-96% against COVID-associated death.
-Effectiveness didn't wane in the 4 months after vaccination.
-Despite the shift away from the JN.1 variant, effectiveness against death with Pfizer's vaccine was 91% against the KP.3.1.1 variant and 76% against the XEC variant.
JN.1-targeted mRNA boosters developed for the 2024-2025 COVID-19 season were effective and safe in Danish seniors, according to two register-based cohort studies that suggested Europe may have selected the better vaccine strain.
Among the 728,768 adults over 65 who received the BNT162b2 JN.1 booster, vaccine effectiveness against hospitalization was 70.2% and effectiveness against death was 76.2%. The 91,461 people given the mRNA-1273 JN.1 booster saw 84.9% effectiveness against hospitalization and 95.8% effectiveness against death. There was no evidence that protection waned in the 4 months after vaccination, reported researchers led by Christian Holm Hansen, PhD, of the Statens Serum Institut in Copenhagen, Denmark, in Lancet Infectious Diseasesopens in a new tab or window.
A separate Danish study showed that the two mRNA vaccines were also safe, with no increase in adverse events of special interest, according to a report in JAMA Network Openopens in a new tab or window from Niklas Worm Andersson, MD, PhD, also of the Statens Serum Institut, and colleagues.
The U.S. and Europe took different approaches to COVID vaccination last season, with the U.S. authorizing or approving KP.2-targeted mRNA vaccines from Pfizer/BioNTech and Moderna and a JN.1-targeted vaccine from Novavax for the 2024-2025 campaign. A CDC analysis published earlier this yearopens in a new tab or window of the FDA-approved shots showed a 45-46% vaccine effectiveness against hospitalization in adults 65 years and older. Critical illness events, including death, were too rare for analysis of effectiveness.
"Our estimates suggest higher vaccine effectiveness than reported in the U.S. study but are broadly consistent with earlier estimates of vaccine effectiveness against hospitalization and death, both from Denmark and internationally," noted Hansen and colleagues, who suggested the differences in efficacy were "probably" a result of study design and the included patient populations. "Despite the lower vaccine effectiveness in the CDC study, both analyses showed sustained protection over 4 months, with little evidence of waning."
Efficacy Data
JN.1 -- a sublineage of the SARS-CoV-2 Omicron variant -- rapidly became the predominant COVID strain in many countries by early 2024.
Hansen's group noted that the BNT162b2 JN.1 booster still packed a protective punch even as the circulating variants fundamentally shifted. By mid-2024, two new variants, KP.3.1.1 and XEC, had largely replaced JN.1. Despite the shift, the BNT162b2 booster delivered 71.7% effectiveness against KP.3.1.1-related hospitalization and 76.8% against XEC-related hospitalization. BNT162b2's effectiveness against death for the two variants was 90.9% and 76.3%, respectively.
"Despite a potential mismatch between the monovalent vaccines (targeting JN.1) and the predominant circulating variants (KP.3.1.1 and XEC), both vaccines were effective in preventing severe COVID-19 disease," Hansen and colleagues wrote. "The JN.1 mRNA vaccine ... effectively boosts low-to-absent pre-vaccination cross-reactive antibodies by 15.3 times against KP.3.1.1 and 11.2 times against XEC."
A close family resemblance among spike proteins may explain the JN.1 boosters' effectiveness against the variant newcomers. The variants' spikes are only four (KP.3.1.1) and five (XEC) amino acid residues off from their JN.1 parent. In contrast, JN.1's own debut during the 2023-2024 season featured more than 30 amino acid differences from the XBB.1.5 variant in that season's monovalent booster vaccine.
Earlier this year, an FDA panel unanimously recommended that COVID vaccines for the 2025-2026 seasonopens in a new tab or window should be a monovalent one in the JN.1 lineage, although members disagreed slightly about which specific strain should be included.
Hansen and colleagues analyzed vaccination data from Denmark's National Vaccination Registry and hospitalization and death data from the National Patient Registry. All had completed a primary vaccination course in 2021 and received the 2023-2024 XBB.1.5 vaccine to minimize differences between groups.
The researchers followed participants from October 2024 to January 2025. Median age was 76 years, and 54.2% were women. By the end of January 2025, 820,229 people had received a JN.1 booster. Those receiving the mRNA-1273 vaccine were generally younger, more often male, and had fewer comorbidities than those receiving the BNT162b2 booster.
Study limitations included the potential for selection bias. Most people were vaccinated within the study period's first month, leaving little unvaccinated time for analysis. Those vaccinated early may be more health-conscious with better health outcomes than those who wait to be vaccinated. In addition, the study's focus on people 65 years or older leaves questions about vaccine effectiveness in younger people.
Safety Analysis
The analysis of registry data included 1,012,400 Danes 65 years or older who received a JN.1 booster vaccine from May 2024 to March 2025, and found no significant increases in the rates of 29 adverse events of special interest to COVID-19 vaccines.
For example, the rate of ischemic cardiac events was 16% lower in the immediate post-vaccination period than in a later reference period, at 44.9 events per 100,000 person-years versus 49.2 events, respectively. Rates of deep venous thrombosis and Guillain-Barre syndrome were 20% (15.3 vs 16.9) and 43% (0.2 vs 0.3) lower, respectively. The rate of myocarditis was numerically higher, however, at 0.5 events per 100,000 person-years in the post-vaccination period, compared with 0.4 events per 100,000 person-years in the later reference period.
Researchers used individual-level data from nationwide healthcare registers in Denmark and compared adverse event rates during the 28 days after booster vaccination with rates during a reference period that began 43 days after vaccination. Adverse events were identified as the first hospital contact that had an adverse-event diagnosis. Mean age of the cohort was 66.8 years and 54.4% were women.
Study limitations include the rarity of some adverse events during follow-up, which could lead to lower statistical precision.
Obviously they did.........
Because ALL of them are WRONG.
The evidence is out there if you care to evaluate it. My vaccinated and boosted wife has had covid three times since getting the shots. I never took the needle and had a mild case of covid once and never had it again thanks to my natural immunity. Lots of people I know, including my wife, are sorry they ever fell for the covid vaccine scam. This was nothing more than collusion between politicians and Big Pharma.
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