Science's COVID-19 reporting is supported by the Pulitzer Center and the Heising-Simons Foundation Last-minute vaccine dosing changes that could gamble away proven COVID-19 protection and undermine public trust. Controversial approvals without any efficacy data. Vaccinemakers at odds with countries hosting their clinical trials. The COVID-19 vaccine landscape keeps changing almost daily, simultaneously raising hopes and triggering confusion and scientific debates. “It's crazy,” says vaccine researcher John Moore of Weill Cornell Medicine. “Every morning, it's just, ‘What's going on?’” Over the past few weeks, COVID-19 vaccines developed in the United Kingdom, China, and India moved toward widespread rollout, offering new weapons in the face of fast-spreading viral variants that threaten to deepen the crisis (see p. 108). But many came with controversies, and U.K. regulators sparked a debate when they endorsed a sharp departure from the expected dosing schedule for a newly authorized vaccine from AstraZeneca and the University of Oxford and one from Pfizer and BioNTech. The pandemic has driven most COVID-19 vaccinemakers to aim for a short 3 or 4 weeks between prime and booster shots, but the U.K. Medicines and Healthcare products Regulatory Agency (MHRA) said second shots can be given up to 12 weeks later.