Shanghai mother Julia Wei has been closely following Covid-19 vaccine development updates. As a frequent business traveller, she believes an effective vaccine will be the key to a return to social and economic normalcy.Yet as progress is made – four out of seven candidates developed in China are being tested for broader safety and efficacy before they can get regulatory approval – Wei said she and her six-year-old daughter would be unlikely to voluntarily get a Covid-19 jab. The public has been…