S. Africa drops AstraZeneca vaccine

LONDON — Developers of the Oxford-AstraZeneca vaccine expect to have a modified jab to cope with the South Africa coronavirus variant by autumn, the vaccine’s lead researcher said Sunday.

South Africa halted use of the vaccine Sunday after evidence emerged that the vaccine did not protect clinical trial volunteers from mild or moderate illness caused by the more contagious virus variant that was first seen there.

The B.1.351 variant has spread to at least 32 countries, including the United States. Pfizer and Moderna have both said that preliminary laboratory studies indicate that their vaccines, while still protective, are less effective against B.1.351.