Here’s a sign the stock market rally hasn’t fully factored in a successful vaccine rollout

Progress toward a COVID-19 vaccine has unleashed the stock-market bulls, helping to push benchmark U.S. stock indexes to all-time highs recently even as the pandemic stages a deadly resurgence heading into year-end.

But investors do have some reservations, according to a monthly survey of clients by Deutsche Bank. Specifically, the biggest risks for next year revolve around scenarios that could see vaccines fail to control the virus.

See: U.S. suffers its worst week of cases, deaths and hospitalizations since the start of the pandemic

Deutsche Bank asked investors to select from a number of risks to global financial markets in 2021. The top worry, cited by nearly 40% of the survey’s 984 respondents, was that mutations would allow the virus to “dodge” the vaccines (see chart below).

Deutsche Bank

The second-biggest concern was emergence of serious side effects.

Fears that a sufficiently large number of people would refuse to take the vaccines, hampering economic recovery, rounded out the top three concerns.

Related: The U.S. is getting closer to COVID-19 vaccine distribution, but only about half of Americans say they’re ready to get the shots

“Interestingly, all the vaccine-related concerns filled out the top three which may suggest that although consensus is for a good 2021, a successful vaccine roll out could still bring upside surprise relative to expectations,” said Deutsche Bank strategist Jim Reid, in a Friday note.

What else were investors worried about?

Number four was a bursting of a technology stocks bubble, followed by policy makers pulling back too quickly on the extraordinary levels of fiscal and monetary stimulus they have provided in response to the pandemic.

Stocks were modestly lower Friday, with the S&P 500 SPX, -0.41%, Dow Jones Industrial Average DJIA, +0.01% and Nasdaq Composite COMP, -0.60% on track for weekly losses as talks toward another round of coronavirus aid by the U.S. government stalled.

U.S. stock indexes remain positive for December, building on vaccine-inspired gains that saw the Dow score its largest monthly rise since January 1987 in November as the benchmarks stretched to all-time highs.

Check out: Stock-market sentiment hitting ‘ludicrous’ territory, but when will bulls ‘pay the piper’?

The U.K. earlier this week began the rollout of the vaccine developed by Pfizer Inc. PFE, -1.48% and BioNTech SE BNTX, -1.70%. In the U.S., the Food and Drug Administration was expected to give emergency authorization of the vaccine as early as Friday.

Also read: What you need to know about an emergency use authorization for a COVID-19 vaccine.