While drug companies are making progress in the quest to find a cure for a disease that triggered the worst recession since the Great Depression, questions remain about how effective the first wave of vaccines would be, how easy they will be to distribute to more than 7 billion people and then how many will agree to take them.

The future for global growth relies on the answers to those questions as a new wave of the pandemic means health fears and government restrictions continue to inhibit daily life and commerce. Even when a successful immunization system does come along, it won’t be an instant economic panacea, says Chris Chapman, a portfolio manager at Manulife Investment, which manages more than $660 billion.

“In terms of actually getting back to pre-Covid or trend growth, it could take more than a year,” said Chapman. “The timing of the recovery will be delayed, but there is still expectation of a vaccine at some point next year.”

For decades, the world economy relied on central bankers and finance ministers to pull it out of crisis, on the basis that if you pump the right amount of money into an economy, a recovery will eventually follow.

This time is different, as investors look to scientists and data from vaccine and treatment trials for signs of hope just as much as they pore over stimulus plans coming out of Washington, Beijing or European capitals. The longer the hunt for an effective vaccine lasts, the weaker economic expansions will be.

To be sure, science could yet make major breakthroughs in the near term. If even only a small proportion of the population such as healthcare workers and the most vulnerable are immunized, that could make a big difference to the resumption of everyday life. Savings built up by households and businesses in 2020 could be unleashed in 2021.

Pfizer Inc. said this month it could seek emergency-use authorization in the U.S. by late November for its vaccine with German partner BioNTech SE. Moderna, another frontrunner in the race, is also looking at the possibility of an emergency approval this year if it has positive interim results next month.

Balancing Act

“There is a fair prospect that by the late spring, vaccines will be available in quantities sufficient to protect the most vulnerable groups,” said Neil Ferguson, an epidemiologist at Imperial College London, and former Covid-19 adviser to the U.K. government. “But at least until then, life will unfortunately remain a balancing act between reopening society and keeping the virus in check.”

Scientific hiccups may slow things down too. Johnson & Johnson paused clinical trials of its Covid-19 shot this month after a participant fell ill, weeks after AstraZeneca Plc and the University of Oxford stopped studies for the same reason. On Friday, both companies announced plans to resume their U.S. trials.

Effective treatments that would also help the economic recovery are also a mixed picture. Disappointing trial results this month for the much-hailed drug remdesivir from Gilead Sciences Inc. showed the antiviral treatment doesn’t save the lives of Covid-19 patients, despite U.S. President Donald Trump extolling its benefits. Still, U.S. regulators cleared the drug for use this week and Gilead has challenged the recent findings citing other positive results.

While there are hopeful signs from some antibody treatments being tested, the steroid dexamethasone is one of the only other therapeutics showing a meaningful benefit, and is aimed at people with very severe symptoms.

Even if an effective vaccine is discovered, the logistics of distribution will still mean disruption to work, travel and leisure will remain, with only a small subset of the population expected to receive a shot in the first instance anyway.

That all spells trouble for global growth, even as data in the U.S. and euro-area are likely to show this week that it rebounded smartly in the third quarter and didn’t collapse as much as once feared.

Long gone though is talk of a V-shaped recovery, as winter nears in the northern hemisphere -- and with it the risk the virus spreads more easily. Bloomberg Economics’s gauges of high-frequency data already point to a weakening of activity in many industrial nations in October, particularly those in Europe.

‘Very Precarious’

“The virus is creating a major element of uncertainty,” former Federal Reserve Chairman Alan Greenspan told Bloomberg Television last week. “Forecasting it is very precarious.”

Underscoring the pressure for an end to the pandemic is the knowledge economic scars are already forming. Among them: lost jobs, record debts, corporate bankruptcies, atrophying skills, missed investment, deglobalization, frayed mental health and rising inequality.

A recent study declared the U.S. economy alone will witness “large, persistent adverse effects” in the long term that outweigh the short-term hit in part because the virus means greater unease among the public.

“This did not start as a financial crisis but it is morphing into a major economic crisis, with very serious financial consequences,” World Bank Chief Economist Carmen Reinhart told Bloomberg Television. “There’s a long road ahead.”

Even in those parts of the world where the virus has been largely contained, consumers remain cautious. Chinese retail sales have only just begun to accelerate even though the most severe limits on movement were lifted months ago.

There is also the question of re-infection. Scientists have found it’s possible to get Covid-19 more than once, with a handful of confirmed cases globally. That presents another obstacle, which a vaccine may only partially solve.

There’s a high chance the coronavirus, like flu, could require regular shots to keep it at bay, meaning the virus could cast an even longer arc than already expected, cautioned Graham Medley, a professor of infectious disease modeling at the London School of Hygiene & Tropical Medicine, and member of the U.K. government’s Covid-19 advisory panel.

“If second and third infections are as infectious as the first infection, and the first generation of vaccines is not very efficacious, then it’s possible that Covid-19 will continue to be a major aspect of life into 2022,” he said.