By Karishma Singh

Here's what you need to know about the coronavirus right now:

Sydney locked down for third week

The leader of Australia's New South Wales (NSW) state on Wednesday ordered a week-long extension of Sydney's COVID-19 lockdown, warning new cases are bound to rise as the country's biggest city grapples with the highly infectious Delta variant. Total infections have topped 350 since the first case, a limousine driver who transported overseas airline crew, was detected three weeks ago in the beachside suburb of Bondi.

While other developed nations have pressed ahead with vaccinating a large portion of their population, fewer than 10% of Australians have been fully vaccinated so far.

South Korea considers reimposing restrictions as cases surge

South Korea reported its second highest number of daily new COVID-19 cases ever on Wednesday, just days after it began easing social distancing restrictions in some parts of the country, buoyed by an accelerated vaccine rollout.

With the majority of the 1,212 new cases coming from densely populated Seoul, officials extended movement curbs in the capital and surrounding regions for at least another week and are considering pushing restrictions back up to the highest level. Prime Minister Kim Boo-kyum said the country's fourth wave of the virus, fuelled by the highly contagious Delta variant, was spreading rapidly, especially among unvaccinated people in their 20s and 30s.

Singapore not counting Sinovac shots in vaccination tally

Singapore has excluded those who received Sinovac Biotech's shots from its national COVID-19 vaccination count, according to the city-state's health ministry. Just over 17,000 people in Singapore have received one dose of CoronaVac as of July 3. These records will be captured in a national immunisation registry.

Sinovac's CoronaVac shot is not part of Singapore's national vaccination programme and the city-state has said it is still awaiting critical data from the company. "COVID-19 vaccines that are not part of our national vaccination programme may not have documented sufficient data on their protection against COVID-19 infection, especially against the Delta variant that is currently circulating," the health ministry said last week.

Mass-testing reduced Liverpool cases by a fifth, study finds

A mass rapid-testing scheme reduced COVID-19 cases in the English city of Liverpool by more than a fifth, researchers said on Wednesday, arguing it was an effective public health intervention despite concerns over accuracy of the devices. The community testing pilot scheme launched in November, and offered everyone in the city tests whether or not they had symptoms, in an attempt to find a new way to use testing to limit the spread of the coronavirus.

The study, led by the University of Liverpool with government backing, concluded that community testing led to an 18% increase in case detection and a 21% reduction in cases compared with other areas up to mid-December.

Biden zeroes in on Delta variant

U.S. President Joe Biden on Tuesday encouraged Americans who have not yet been vaccinated against COVID-19 to get their shots to protect themselves from the widely-spreading, highly contagious Delta variant of the coronavirus.

The Delta variant, which is becoming dominant in many countries, is more easily transmitted than earlier versions of the coronavirus and may cause more severe disease, especially among younger people. It has now been found in every U.S. state, health officials have said.