Overview: Summary of international COVID-19 related developments

Factbox: Latest on the worldwide spread of the coronavirus Nations from Australia to Vietnam announced more drastic curbs and longer lockdowns on Friday, as authorities struggle to rein in outbreaks of the highly infectious Delta variant. Reuters Reuters

* The mass rollout of booster vaccines in Britain to people over 50 this autumn could be shelved, with government scientists considering limiting third doses only to the most vulnerable, the Telegraph reported. read more

* The European Commission said it had reached a temporary agreement with South Africa to use a plant there to bottle Johnson & Johnson (JNJ.N) vaccines that are being imported into the EU, after criticism of the arrangement.

* Two million residents of Sydney will be under nightly curfew from next week to slow the Delta variant that is spreading across New South Wales state, authorities said as they extended lockdown orders.

* Prime Minister Jacinda Ardern urged New Zealanders to stick to her strategy to eliminate the Delta variant as she extended a strict lockdown amid a surge in infections. read more

* Vietnam will deploy troops in Ho Chi Minh City and prohibit residents from leaving their homes, authorities said, as its biggest city turns to drastic measures to slow a spiralling rate of coronavirus deaths. read more

* Japan plans to dramatically ramp up daily tests, borrowing from anti-contagion measures used in the recent Tokyo Olympics, as it battles its worst wave of infections, driven by the Delta variant. read more

* AstraZeneca (AZN.L) said its antibody therapy met the main goal of preventing COVID-19 in a late-stage study, putting the British drugmaker on track to potentially offer an alternative to vaccines for people with weakened immune systems. ...