mRNA COVID vaccines protect against severe Omicron for at least half a year

COVID-19 mRNA booster vaccines offered protection against severe COVID-19 caused by the Omicron variant for at least 6 months, and three doses of China’s inactivated vaccines were more protective than two doses but not as protective as three doses of mRNA vaccines, finds a study from Singapore published today in JAMA Network Open. Researchers at the National Centre for Infectious Diseases in Singapore studied the effectiveness against infection and severe illness of two or more doses of the Pfizer/BioNTech or Moderna mRNA COVID-19 vaccines or the inactivated Sinovac, CoronaVac, or Sinopharm Chinese COVID-19 vaccines in 2,441,581 residents aged 30 years or older from Dec 27, 2021, to Mar 10, 2022, during Omicron predominance. Of all participants, 52.4% were women, and 34.7% were 60 years or older. A total of 90.2% of all participants received three doses of COVID-19 vaccine by the end of the study period, 97.8% of them with an mRNA...