With younger people increasingly coming in for treatment with more serious cases of COVID, doctors fear health systems could become overwhelmed

The ECD notes 'considerable uncertainty related to transmissibility, vaccine effectiveness, risk for reinfections and other properties'

Pharmaceutical company says it is also examining using a higher dose of its existing vaccine against new strain

US, Canada, Russia, Israel and a host of other countries join European Union in restricting travel for visitors from southern Africa; 'It seems to spread rapidly,' says Biden

African nation, which has much lower infection rates than much of Europe, says countries must not be punished for scientific research into mutations; WHO also rejects travel bans

Starting Monday, America will limit travel from South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi; Fauci says more info on variant still needed

Jewish virologist Barry Schoub, who advises the government, says data so far indicates vaccines protect against severe illness from new COVID variant

Firm that developed vaccine with Pfizer says it will have more data available next month, but has plans in motion to be able to mass-manufacture adapted inoculation

Officials say it will take weeks to understand implications of newly discovered strain, call for measured action

Airlines, travel stocks and major indexes plunge amid investor uncertainty over potential reversal of progress at getting pandemic under control