Just when pandemic risks seemed to be declining, thanks mainly to vaccinations for nearly all ages, we're slapped in the face by a Covid variant (new type) called omicron. Signs suggest it may be more contagious than an earlier mutant called Delta and more likely to cause "breakthrough" infections among vaccinated people. The World Health Organization last week said Omicron poses a very high risk to public health. (The variant, named after a Greek letter, is pronounced OH-muh-kraan.) After the first American case was confirmed in California last Wednesday, the latest variant was diagnosed in at least four other states (Minnesota, Colorado, New York and Hawaii).

The United States and some other countries bar foreign travelers from eight countries in southern Africa, where the new strain began. Even though scientists have much to learn about Omicron, "waiting until all the facts are in will leave us hopelessly far behind," warns the health school dean at Brown University in Providence, R.I. "The global community must take each variant seriously. Acting early is far superior to waiting until all the facts are in."

Dr. Anthony Fauci, the president's chief medical adviser, said at the White House: "It might be more transmissible and it might elude some of the protection of vaccines. But we don't know that now." The chief executives of drugmakers Pfizer and Moderna say it will take about two weeks to know what impact Omicron's mutations have on the effectiveness of current vaccines. It would take until early 2022 to develop a shot targeting the variant, they add.

U.S. expert says: "It is extremely unlikely that Omicron will render the Covid-19 vaccines completely ineffective." -- Dr. Ashish Jha, dean of Brown University's School of Public Health

Governor says: "There's no reason to panic -- but we should remain vigilant. That means get vaccinated. Get boosted. Wear a mask indoors." – Gov. Gavin Newsom of California

Health reporter says: "Assuming the worst about each worrisome new variant is not a science-based, rational response. And alarmism has its own costs, especially to mental health." – David Leonhardt, The New York Times