Existing vaccines and booster shots against COVID are sufficient to prevent Omicron infections, said top infectious disease expert Dr Anthony Fauci, as he advised against changing the vaccines to fight the new, highly contagious strain of the virus at this time.

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It has been known that Omicron evades efficacy from the current two-dose shots. A study from South Africa showed that protection from the two-dose vaccine against infection dropped to 33 per cent compared with 80 per cent before the emergence of Omicron.

However, two doses are still 70 per cent effective at preventing hospitalisation in Omicron patients in South Africa, Fauci told the public during a White House COVID update on 15 December, the CNBC reported. "Our booster vaccine regimens work against Omicron. At this point, there is no need for a variant-specific booster. "Obviously, this is significantly down but there is the maintaining of a degree of protection against hospitalisation," Fauci said.

As a result, a booster dose has been advised by several countries. A booster dose increases protection against symptomatic disease to 75 per cent, Fauci said, citing data from the UK Health Security Agency, the report said. "And so the message remains clear. If you are unvaccinated, get vaccinated, and particularly in the arena of Omicron if you are fully vaccinated, get your booster shot," he said.