The virus that causes COVID-19 is constantly changing, and new variants of the virus are expected to occur. The Omicron variant spreads more easily than the original virus and can infect people who have been vaccinated or have previously had COVID-19. Omicron has multiple sub lineages that are classified as variants of concern. CDC publishes information about the proportion of variants in the U.S. every week on its website. COVID-19 vaccines remain the best public health measure to protect people from COVID-19 and reduce the likelihood of new variants emerging.
The CDC recommends eligible people 6 months and older receive an updated, bivalent Pfizer or Moderna vaccine that offers better protection against variants. Some people, like those who are immunocompromised or over 65, are eligible for a second bivalent dose.
The CDC has guidance for everyone 6 months and older based on age and medical condition. People who are up to date with their COVID-19 vaccines and get COVID-19 are less likely to develop serious illness than those who are unvaccinated and get COVID-19.