The new travel restrictions, which bar entry to any person who has travelled through or from South Africa, will come into effect on Saturday 30 January 2021.
Biden revered an order from President Donald Trump in his final days in office that called for the relaxation of the travel restrictions as of Tuesday.
"Out of an abundance of caution and leveraging the flexibility of our mRNA platform, we are advancing an emerging variant booster candidate against the variant first identified in the Republic of South Africa into the clinic".
On Tuesday, new CDC rules take effect requiring all global air travelers aged 2 and older to present a negative coronavirus test taken within three calendar days of travel or proof of recovery from COVID-19 to enter the United States.
President Joe Biden has issued a travel ban on South Africa, stopping most immigration to the United States from the country, and reinstated bans on Europe and Brazil to slow the spread of the Chinese coronavirus.
The White House on Monday night (South African time) confirmed that new US President Joe Biden had signed the relevant order.
"With the pandemic worsening, and more contagious variants emerging around the world, this is not the time to be lifting restrictions on worldwide travel", White House press secretary Jen Psaki said on Twitter.
Last week, Biden moved to expand on the CDC requirement and direct that federal agencies require worldwide travellers to quarantine upon arrival in the US and obtain another negative test to slow the spread of the virus.
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Although worldwide flights between South Africa and the USA have been severely limited since the start of the global outbreak and, more so, during the coronavirus' second wave, there are a few airlines which will have to suspend active routes due to the most recent restrictions.
Traveller's who have tested positive for he coronavirus within three months of their scheduled departure are not advised to undergo further testing, due to the prevalence of false-positives and are, instead, required to produce "documentation of recovery" as described by the CDC. The ban was extended to European countries on March 14 as the pandemic entered full force.
U.S. biotechnology firm Moderna on Monday said lab studies showed its COVID-19 vaccine would remain protective against variants of the coronavirus first identified in the United Kingdom and South Africa.
"It's clearly good news", said Toronto-based infectious disease specialist Dr. Isaac Bogoch, a member of Ontario's vaccine distribution task force.
The emergence of new variants in Britain, South Africa and Brazil has created some concern that mutations in the virus may make vaccines less effective.
The greater concern for scientists right now isn't the current slate of known variants - which may be both more-transmissible and, in the case of B117, possibly more deadly - but those that could emerge in the future.
The report comes after similar news from Pfizer-BioNTech, which released data last week, also not yet peer-reviewed, showing that antibody-rich blood serum samples from 16 vaccinated people showed that vaccine was equally as effective at blocking the British variant as it was against the original version of the virus that took hold in Wuhan, China, a year ago.