Read the full article on The Conversation here.

From the article: 

Generally, good vaccines have three essential features. First, they must be safe to administer. Second, they must produce the appropriate type of immunity (antibody and/or cell-mediated) for the disease in question. Third, they must be inexpensive for the target population and they must take into account geographical, gender and age differences.

References: Ganiyu, A.O. 2020. "Pressure is on to develop a COVID-19 vaccine, but corners can’t be cut". The Conversation.