On August 31, the U.S. Food and Drug Administration revised the emergency use authorization for Modena and Pfizer covid-19 vaccines, and approved specific age groups to vaccinate the upgraded versions of these two vaccines as booster injections to provide better protection against Omicron variants. The FDA said in a statement that the upgraded version of the vaccine is a bivalent vaccine that can target the original strain of novel coronavirus and the new subtypes ba. 4 and Ba of the Omicron variant of novel coronavirus 5 spike proteins play a role. According to the authorization of the U.S. drug administration, the public can receive the upgraded Modena or Pfizer vaccine as a single dose booster at least two months after completing the initial vaccination or booster vaccination. The upgraded Modena vaccine is applicable to people aged 18 and above, and the upgraded Pfizer vaccine is applicable to people aged 12 and above. According to the FDA, BA. 4 and ba The new subtype 5 is the dominant strain in the United States. It is expected that these two new subtypes will continue to spread in the autumn and winter of this year. Robert kalif, director of the US drug administration, said in a statement that the time for public indoor activities will be increased after the fall, and it is strongly recommended that eligible members of the public should be vaccinated with an upgraded version of the vaccine to better resist the currently prevalent variant strains. (news agency)