Here's what you need to know about the coronavirus right now: Sinovac vaccine appears safe, slightly weaker in elderly Chinese firm Sinovac Biotech Ltd said on Monday its coronavirus vaccine candidate appeared to be safe for older people, according to preliminary results from an early to mid-stage trial, while the immune responses triggered by the vaccine were slightly weaker than in younger adults. Sinovac's candidate CoronaVac did not cause severe side effects in a combined Phase 1 and Phase 2 trials launched in May involving 421 participants aged at least 60, Liu Peicheng, Sinovac's media representative, told Reuters. The complete results have not been published and were not made available to Reuters. CoronaVac is being tested in Brazil and Indonesia in final-stage human trials to evaluate whether it is effective and safe enough to obtain regulatory approvals for mass use. It has already been given to tens of thousands of people, including about 90% of Sinovac employees and their families, as part of China's emergency inoculation scheme to protect people facing high infection risk. The World Health Organization is working with China on requirements for international approval of any Chinese COVID-19 vaccine, a senior official said on Monday. Australian states' contact-tracing system Australia's Victoria state, which is at the centre of the country's second wave coronavirus outbreak, is deepening its contact tracing programme to try to maintain a steady decline in daily new cases, amid criticism of its handling of the crisis. Federal Health Minister Greg Hunt told radio station 3AW on Tuesday that Victoria might have avoided a second wave and been able to ease restrictions sooner if its virus tracing system was more than like that of New South Wales (NSW). Prime Minister Scott Morrison has warned of the cost of the Melbourne lockdown to the national economy. State Premier Daniel Andrews, while not directly accepting criticism, said on Monday he would set up five 'suburban' contact tracing teams specialising in geographic parts of the state, which would make it easier to target specific locations where people had been infected. South Korea weighs extension of curbs Authorities in South Korea are weighing whether to extend its social distancing curbs ahead of the Chuseok holiday this month, one of the country's biggest holidays, which would see tens of millions of people travel nationwide. Though the country has continued to post three-digit rises in new daily coronavirus infections, the daily tally has steadily dropped since it reached a peak of 441 last month after the government imposed unprecedented social distancing rules to blunt a second wave of outbreaks from churches and political rallies. President Moon Jae-in said the daily numbers are expected to drop below 100 by the holiday, though health officials have urged against visits and gatherings. Travel bubble plans suspended A spike in coronavirus infections in Indonesia's holiday island of Bali and Thailand's first locally transmitted case in 100 days have dealt further blows to Southeast Asian hopes of reviving vital tourism industries. As well as trying to encourage domestic tourism industries, some Southeast Asian countries have been considering 'travel bubbles' with others as a way to get businesses restarted. But Thailand, for example, suspended those plans in August as new daily coronavirus cases rose in parts of Asia. Yuthasak Supasorn, governor of the official Tourism Authority of Thailand (TAT), told Reuters he hoped it would still start during Europe's winter - Thailand's tourist high season.