NEW YORK, Sept 11: Pfizer and BioNTech said their updated mRNA COVID-19 vaccine for the 2025–2026 season generated strong immune responses, increasing neutralizing antibody levels by at least fourfold in older adults and people with underlying medical conditions.

The companies reported the phase 3 trial results on Tuesday, noting the positive findings come as Americans face a confusing patchwork of access rules that vary by state. Under Health Secretary Robert F. Kennedy Jr., a vocal vaccine opponent, federal approvals were narrowed. Unlike during the previous Trump administration, when vaccines were available to all Americans aged six months and older, the Food and Drug Administration (FDA) has now restricted eligibility to people 65 and older and those under 64 with specific health conditions.

The trial enrolled 100 participants, including 50 people aged 65 and older and 50 people aged 18 to 64 with conditions such as asthma, diabetes, heart disease, HIV, obesity, smoking, Parkinson’s disease, or mental health disorders. All had received last season’s vaccine at least six months earlier and had not been infected with COVID-19 since.

This year’s shot targets the LP.8.1 strain, part of the JN.1 variant family. In both trial groups, antibody levels rose at least fourfold, with no new safety concerns reported compared to earlier vaccine versions. Although LP.8.1 was the dominant strain when regulators made their decision, the leading variant is now XFG, another JN.1 relative. Pfizer said earlier mouse studies indicate the LP.8.1 vaccine remains effective against XFG and other emerging variants, offering stronger protection than last year’s shot.

Despite the encouraging trial data, vaccine access remains uneven. According to the Common Health Coalition, funded by Kaiser Permanente, as of September 8 eligible people in 10 states still require a prescription to receive the vaccine. Off-label use for healthy children and adults is restricted nationwide. Several states have taken steps to clarify or ease access, but rules continue to vary.