New SARS-CoV-2 variants continue to reshape the pandemic, and the evidence so far paints a mixed picture. The B.1.1.7, B.1.351, and P.1 lineages all show clearly increased transmissibility, but data on whether they cause more severe illness or higher reinfection rates remain uncertain. Vaccine performance is similarly variable: Pfizer and AstraZeneca hold up well against B.1.1.7 for symptomatic disease, although AstraZeneca seems less protective against asymptomatic infection. Findings for B.1.351 are inconsistent, with two adenovirus-vector vaccine trials showing reduced protection for mild cases but preserved protection against severe outcomes. Little is known about P.1 or Moderna, and early signals suggest the B.1.617 “double mutant” may reduce Pfizer’s effectiveness. Overall, the evidence base is growing but key gaps remain as these variants continue to spread.