China's COVID-19 vaccine trial is showing promise. The result was published by the world's leading medical journal The Lancet. It comes after 28 days of observation in more than 100 healthy adults, who showed a notable immune response. The final results will be evaluated in six months. The lead researcher said the results represent an important milestone, but should be interpreted with caution. He also warned that there is still a long way to go before this vaccine becomes available.