Markets rose last Wednesday on fresh hopes of the development of a coronavirus vaccine. Investors may be getting ahead of themselves, cautioned OANDA analyst Jeffrey Halley, who warned the "v-shaped recovery gnomes are, once again, reaching for the sky" based on a vaccine trial from Pfizer and BioNTech containing only 45 people. Of course, there are many other vaccine candidates. The World Health Organisation (WHO) is tracking 147 of them, 18 of which are being evaluated in clinical trials.

Last month, the chief investment officer of Pictet Wealth Management, one of Europe's largest asset managers, said there is an 80 per cent chance of a vaccine by the end of 2020. Jared Holz of Jefferies is also optimistic. Based on conversations with several vaccine developers, he recently predicted American regulators would likely approve "at least one vaccine" prior to November and that "multiple vaccines could get the go-ahead at some point early in the fourth quarter". If markets are pricing in such a scenario, investors may end up being disappointed, according to the so-called super-forecasters tracked by the Good Judgement Inc. Only 26 per cent of the super-forecasters, popularised by predictions expert Prof Philip Tetlock and famous for their probabilistic approach, expect a vaccine to be widely available before April 2021.

Four in 10 say we will have to wait until at least October 2021. Investors should hope for a 2020 vaccine, but it may be unwise to bet on it.