Pfizer says this season’s COVID shot boosts immune responses fourfold
Positive results come as Americans face confusing access rules that vary by state.
In Pfizer and BioNTech’s latest trial, the companies limited enrollment to these groups. The phase 3 trial included 100 people total, 50 people age 65 or older and 50 people age 18 to 64 with an underlying condition. Those conditions included asthma, diabetes, heart conditions, HIV, mental health conditions, Parkinson’s disease, obesity, or smoking. All participants had gotten last season’s COVID shot at least six months prior to the trial and had not gotten any other COVID-19 vaccines or a COVID-19 infection since then.