Since Covid-19 vaccines became widely available, there has been a wide gap in deaths between the vaccinated and unvaccinated. But recent Covid deaths are much more evenly split as highly transmissible variants take hold, vaccine protection wanes and booster uptake stagnates. In the second half of September - the height of the Delta wave - less than a quarter of all Covid-19 deaths were among vaccinated people, federal data shows. But in January and February, amid the Omicron surge, more than 40% of Covid-19 deaths were among vaccinated people. The unvaccinated are still far more likely to be hospitalized or die than people who are vaccinated with at least two doses of the Moderna or Pfizer/BioNTech mRNA vaccines or a single dose of the Johnson & Johnson vaccine. Of those vaccinated people who died from a breakthrough case of Covid-19 in January and February, less than a third had gotten a booster shot, according to a CNN analysis of data from the US Centers for Disease Control and Prevention. The remaining two-thirds had only received their primary series. Overall, the risk of dying from Covid-19 is still about five times higher for unvaccinated people than it is for those vaccinated with at least their primary series, CDC data shows.