In just 36 hours, researchers analysed samples from 100 infected patients, collated the data and, as Americans were enjoying Thanksgiving, alerted the world, setting off new rounds of travel restrictions and adding uncertainty about the trajectory of a pandemic that has upended the world for almost two years.
Omicron has reached more than 40 countries, although most of the cases so far have been found in arriving travellers. According to scientists in South Africa, omicron appears to spread faster than any other variant, thanks to a combination of contagiousness and an ability to dodge the body’s immune defences. But the contribution of each factor is not yet certain.
International concern has not waited for a fuller picture to take shape. The World Health Organization acted with alacrity. In an emergency meeting the day after South Africa flagged the variant, WHO labelled omicron a “variant of concern,” its most serious category, a distinction it shares with the delta variant.
Even before the WHO meeting was over, more than 10 countries, including the United States, had announced they would close their borders to travellers from southern Africa. Japan, Israel and Morocco went a step furthering, sealing themselves off completely to foreign travellers.
The discovery of omicron prompted a swift reconsideration of the need for booster shots. On Monday, the Centers for Disease Control and Prevention strengthened its guidance by urging all eligible adults to get their third shot.
Vaccine makers said they were confident they could tailor existing formulas to defend against the variant, but the process was expected to take months. Scientists in South Africa reported an increase in reinfections in people who already had a bout of COVID, suggesting that the variant could overcome natural immunity.
Omicron was soon found in several European countries, including the United Kingdom, as well as in Australia, Israel and Hong Kong. By Tuesday, with cases documented in at least 20 countries, health officials said the variant had been in Europe several days earlier than previously known.
The first US case of the omicron variant of the coronavirus was reported in California on Wednesday in a San Francisco resident who had recently traveled to South Africa. Since then, it has been identified in at least 11 other states, from Hawaii to New York. Officials are bracing for more community spread, having identified at least one case stemming from domestic travel and another with no recent travel history.
On Thursday, President Joe Biden announced a broader strategy to fight the pandemic that goes beyond vaccines to underscore frequent testing as an essential mitigation tool. The new plan includes reimbursing the 150 million Americans with private insurance for at-home tests starting early next year.
To ensure access for those who lack insurance, or who are covered by Medicaid, the administration intends to distribute an additional 25 million tests to community health centers and rural clinics.
The president also rolled out stricter testing requirements for international flyers to the United States, requiring a negative result from a test taken within 24 hours of departure. Mask mandates for travellers were extended until mid-March.
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