STUDY: "A fourth vaccine dose was associated with a decreased risk of being diagnosed with post #COVID19 condition, with a vaccine effectiveness of 31%." A fourth vaccine dose in those with risk factors for severe acute COVID-19 had a "vaccine effectiveness of 38% for the fourth dose against post COVID-19 condition." https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(26)00468-2/fulltext