(Reuters) - AstraZeneca is due to publish up-to-date results from its major U.S. COVID-19 vaccine trial, after health officials publicly criticized it for using “outdated information” to show how well the immunization worked. Here’s a look at the progress of the vaccine development to date since its inception. JANUARY 2020: A team involving Oxford Vaccine Group and Jenner Institute starts work on developing a vaccine to prevent COVID-19. MARCH 2020: Researchers at the Oxford University begin screening healthy volunteers, aged 18-55, for recruitment in the ChAdOx1 nCoV-19 vaccine trial in the Thames Valley Region. APRIL 2020: Human trials begin AstraZeneca and Oxford join forces for development and potential large scale distribution of the vaccine candidate. MAY 2020: AstraZeneca and Oxford start recruiting volunteers for a much larger human trial in the UK. JULY 2020: Initial safety data released showed vaccine was safe and produced an immune response. AUGUST 2020: Vaccine candidate begins late-stage study in the United States. SEPTEMBER 2020: AstraZeneca suspends global trials due to an unexplained illness in a study participant. AstraZeneca resumes UK trials. Oxford/AstraZeneca begin submitting data to the UK regulator under a rolling review process. OCTOBER 2020: EU launches real-time review of the vaccine. United States restarts trial, the last one to do so after other regions began resumption much earlier. NOVEMBER 2020: AstraZeneca confirms that the UK regulator has started an accelerated review of vaccine. Interim late-stage data from UK, South Africa trials released: The vaccine on average prevented 70% of COVID-19 cases in late-stage trials in Britain and Brazil. The success rate rose to 90% in a group of trial participants who accidentally received a half dose followed by a full dose. The efficacy was 62% if the full dose was given twice, as it was for most study participants. DECEMBER 2020: Britain approves shot in first for COVID-19 vaccines in the West. Regulators said that the higher efficacy seen in the half-dose/full-dose cohort was likely a result of a longer gap between doses, rather than the amount of vaccine given. JANUARY 2021: India approves Serum’s vaccine days later in early January. Europe gives vaccine green light in late January. FEBRUARY 2021: The World Health Organisation gives the vaccine a go-ahead. MARCH 2021: AstraZeneca cut its first-quarter supply forecast to the EU due to export constraints. Austria halts use of one batch of vaccine following reports of cases of blood clots in Nordic countries. More than a dozen European countries, including Germany and France, followed suit and halted use of the vaccine. European regulators and WHO back vaccine’s safety in mid-March. In late March, interim data from late-stage trials in U.S., Peru, Chile shows vaccine is 79% effective. The U.S. National Institute of Allergy and Infectious Diseases said the drugmaker may have included outdated information from the trial, providing an incomplete view of the efficacy data.