A 90-year-old British grandmother became the first person in the West to receive an approved COVID-19 vaccine on Tuesday. It was a seminal moment in the coronavirus pandemic, which has claimed more than 1.5 million lives and forced the shutdown of large swaths of the global economy.

The distribution of vaccines throughout the next year is expected to trigger an economic boom, allowing businesses that were closed to slow the spread of the virus to reopen, while unleashing a wave of pent-up demand.

But economists are already warning that the rebound may not play out as dramatically as some expect.

“The recovery will be strong by historical standards, for many it won’t feel that way and there may be bumps and volatility ahead,” Ben May, director of global macro research at Oxford Economics, said in a research note published this week.

May expects global GDP growth next year to be the strongest since the late 1970s — a big enough upswing to return output to pre-crisis levels by the summer. But given that the surge would just restore the status quo, it’s “unlikely to feel like the best year in over four decades.”

Some industries will feel the effects more than others. Industrial production has been resilient and is likely to ramp up quickly, while the services sector — particularly long-haul travel — is poised to accelerate more slowly, May said.

Neil Shearing of Capital Economics believes global GDP can be back at pre-virus levels by the middle of next year. But in a recent note to clients, he observed that the world economy won’t return to its previous trajectory until 2024.

He also pointed out that countries won’t recover in unison given the uneven impact of the virus. Spain, India, France and the United Kingdom, for example, have been hit particularly hard and “remain depressed,” while China is bounding ahead.

“The virus has produced a wide variation in economic outcomes,” Shearing said. “These divergences won’t disappear in 2021, but they are likely to narrow as vaccines are rolled out and the hardest hit economies start to find their feet.”

Watch this space: Long-term scarring will depend in part on what happens in the coming months, as restrictions are reimposed during a tough winter. Hong Kong is tightening social distancing measures to counter a fourth virus wave, while the United States is adding to its case numbers at its fastest rate ever after the Thanksgiving holiday.

“Despite the more encouraging near-term outlook, we nevertheless see significant downside risks if colder temperatures in coming months and the limited policy and consumer policy response so far mean that virus spread rises to much higher levels,” Goldman Sachs’ US economists said Sunday.