New data from clinical trials of the AstraZeneca-Oxford University COVID-19 vaccine suggest it provides strong protection after the first of two doses and could slow the spread of the virus, according to a new preprint study.The development comes amid a flurry of other vaccine developments today and as health officials look more toward spacing out the two-dose vaccines as a way to protect more people, especially as the threat of more transmissible variants and ones that can escape immunity darken the horizon.Data affirm UK prime-boost timingIn a preprint in The Lancet, researchers published another month's worth of data and combined findings from four trials that took place in the United Kingdom, South Africa, and Brazil.