• Biden officials try to assure a vexed public that vaccination snarls will be ironed out.

• Mexico’s president is the latest world leader to become infected with the coronavirus.

• Vaccines alone will not haltthe raging U.S. pandemic, modeling shows. 

• Travel from South Africa to the U.S. will be banned to curb spread of variant.

• Vaccinations are lagging in South Carolina, a hot spot for the virus.

• Variants threaten to undo progress in fighting the virus, health experts warn.

• Israel stops air travel in and out of the country, in effort to block virus variants from entry.

• Egypt begins its vaccination campaign with 50,000 doses from China’s Sinopharm.