WASHINGTON — Nearly 1,000 infection cases of coronavirus variants have been reported in a total of 44 US states, according to the latest data of the US Centers for Disease Control and Prevention (CDC).

The vast majority of these cases, 981, were caused by the variant known as B.1.1.7, which was originally detected in Britain.

There were 13 cases of a new strain initially discovered in South Africa, called B.1.351, and three cases of the P.1 strain first discovered in Brazil.

These are the three dominant coronavirus variants currently spreading in the United States, according to the CDC.

Numerous SARS-CoV-2 variants have emerged over the last several months, attracting the attention of health and science experts worldwide.

The B.1.1.7 and B.1.351 concern scientists because of emerging data suggesting their increased transmissibility, according to an article published Friday in the Journal of the American Medical Association (JAMA).

Variants can carry several different mutations, but changes in the spike protein of the virus, used to enter cells and infect them, are especially concerning. Changes to this protein may cause a vaccine to be less effective against a particular variant, according to the study written by Anthony Fauci, the nation's top infectious disease expert, and other researchers.

The authors note that the B.1.351 variant may be partially or fully resistant to certain SARS-CoV-2 monoclonal antibodies currently authorized for use as therapeutics in the United States.

A new SARS-CoV-2 variant, CAL.20C, has been detected in southern California amid a surge in local infections and is spreading through and beyond the United States, according to another research letter published in JAMA.

By Jan 22, the variant had grown to account for 35 percent of all coronavirus strains in California and 44 percent of all samples in the southern part of the state and had been detected in 26 states as well as other countries, according to the study by researchers at Cedars-Sinai Medical Center in Los Angeles.

The recognition of all new variants, including the novel emergent strain in California, requires systematic evaluation, according to the researchers. The rise of these variants is a reminder that as long as SARS-CoV-2 continues to spread, it has the potential to evolve into new variants.

The fight against SARS-CoV-2 and COVID-19 will require robust surveillance, tracking, and vaccine deployment worldwide, said the studies.

Researchers also note the need for a pan-coronavirus vaccine. Once researchers know more about how the virus changes as it spreads, it may be possible to develop a vaccine that protects against most or all variants.

The United States has recorded over 27.5 million cases with more than 481,600 related deaths as of Saturday afternoon, according to the real-time count kept by Johns Hopkins University.