Viruses constantly change through mutation and sometimes these mutations result in a new variant of the virus.
Some variants emerge and disappear while others persist as in the case of coronavirus strains known as Delta and Omicron.
New variants will continue to emerge. CDC and other public health organizations monitor all variants of the virus that causes COVID-19 in the United States and globally.
The Delta variant causes more infections and spreads faster than the original SARS-CoV-2 strain of the virus that cause COVID-19.
Omicron is spreading like wildfire.
The Centers for Disease Control and Prevention says omicron is now the dominant variant nationwide — making up an estimated 59 percent of infections for the week ending Dec. 25.
However, it also revised down the estimated proportion of omicron cases for the week before that — a change that suggests the delta variant was in fact responsible for many more recent infections than previouslyexpected.
The latest CDC data suggests omicron was responsible for 23 percent of cases in the week ending Dec. 18, a significant drop from its earlier estimate of 73 percent.
Also on Tuesday, the CDC released the findings of an investigation into one of the earliest omicron clusters in the United States that indicates the variant could have a shorter incubation period, of about three days, than previous versions of the virus.
Vaccines and booster doses are recommended for adults ages 18 and older.
Teens 16–17 years old who received Pfizer-BioNTech COVID-19 vaccines can get a booster dose if they are at least 6 months post their initial Pfizer-BioNTech vaccination series.
Vaccines remain the best way to reduce your risk of severe illness, hospitalization, and death but wearing a mask is an effective way to reduce the spread of earlier forms of the virus, the Delta variant and other known variants.
People who are not fully vaccinated should take steps to protect themselves, including wearing a mask indoors in public at all levels of community transmission.
People who are fully vaccinated should wear a mask indoors in areas of substantial or high transmission.
While advances have been made in the treatment of people infected with coronavirus, the disease has killed two percent of those who contract it.
Areas with low percentages of vaccinated population are likely to suffer greater death tolls and nurture new variants that may break through with even more deadly consequences.