A study published in JAMA Internal Medicine evaluated the effectiveness of the BNT162b2 XBB vaccine against COVID-19 in US adults. The study, conducted between October 10 and December 10, 2023, involved 2854 cases of COVID-19 and 15,345 controls. The BNT162b2 XBB vaccine showed a 62% effectiveness against hospitalization and 58% against emergency department (ED) or urgent care (UC) visits. These results were based on adjusted odds ratios from multivariable logistic regression models. The study also found that older versions of the vaccine provided little to no additional protection compared to unvaccinated individuals. The findings support the recommendation for broad age-based use of annually updated COVID-19 vaccines. The study highlights the importance of updating vaccines to address new variants like XBB, which were dominant in the US during 2023. Despite the vaccine's effectiveness, uptake remains low, with only 19% of adults 18 and older and 37% of those 65 and older receiving the XBB vaccine by December 2023. The study also notes that vaccine effectiveness may decrease over time, emphasizing the need for regular updates. The results reaffirm the importance of annual vaccine updates to maintain protection against COVID-19.A study published in JAMA Internal Medicine evaluated the effectiveness of the BNT162b2 XBB vaccine against COVID-19 in US adults. The study, conducted between October 10 and December 10, 2023, involved 2854 cases of COVID-19 and 15,345 controls. The BNT162b2 XBB vaccine showed a 62% effectiveness against hospitalization and 58% against emergency department (ED) or urgent care (UC) visits. These results were based on adjusted odds ratios from multivariable logistic regression models. The study also found that older versions of the vaccine provided little to no additional protection compared to unvaccinated individuals. The findings support the recommendation for broad age-based use of annually updated COVID-19 vaccines. The study highlights the importance of updating vaccines to address new variants like XBB, which were dominant in the US during 2023. Despite the vaccine's effectiveness, uptake remains low, with only 19% of adults 18 and older and 37% of those 65 and older receiving the XBB vaccine by December 2023. The study also notes that vaccine effectiveness may decrease over time, emphasizing the need for regular updates. The results reaffirm the importance of annual vaccine updates to maintain protection against COVID-19.