By Nat Ives

Clydesdales gallop and bars display "Open" signs in Budweiser's newest ad, part of marketers' efforts to mark the latest stage in the coronavirus pandemic: the reopening.

The sad piano scores of early-pandemic advertising are gone. Sometimes, so are the safety promises that followed in the next wave of ads -- like Domino's Pizza Inc.'s pledge that nobody touches its pizzas between the oven and the customer, or WeatherTech's reminder that its car floor mats "can be easily wiped with germ-killing disinfectants."

Calls to be responsible or safe often take their place, but not always.

Ads promoting Las Vegas illustrate the shift. A commercial last month from the Las Vegas Convention and Visitors Authority promised a "more intimate" Vegas with "more space" when it was again ready for guests -- nods to social distancing even in a crowded tourist destination.

This month, a new ad from the organization simply shows a darkened Las Vegas Strip lighting up after somebody flips a big switch. "Now Open," it says.

A Macy's Inc. TV ad last week assured shoppers that its stores are reopening responsibly and with precautions; this week, a Macy's commercial promotes discounts.

As governments loosen restrictions related to the virus, marketers are wooing millions of cooped-up consumers who can increasingly venture back to hair salons, restaurants and other venues that were forbidden for months. The new stage of the pandemic means ads don't have to be somber as often as they were in the spring, marketers said.

The question is how carefree they should be.

"The phase we're in now is a phase of euphoria," said Pedro Earp, global chief marketing and ZX Ventures officer at Budweiser parent Anheuser-Busch InBev SA. People who are tired of being locked down see an opportunity to resume elements of normal life, he said.

In another ad that projects optimism, AB InBev calls out ways that it is helping during the pandemic, such as supporting local bars and making hand sanitizer. "Together we're making it happen," a voice says before asking consumers to contribute ideas for more good works, adding, "Let's dream big together."

But brands can't act like the danger is gone, according to Mr. Earp, who predicted that any euphoria now will be followed by anxiety as consumers realize the virus is still here. "We just launched a campaign in Argentina asking people to come out of the lockdown in moderation and to do everything safely," he said.

The new Budweiser ad tries to combine excitement and responsibility. "We can't wait to see our buds," it says on the screen as the energetic Queen song "Don't Stop Me Now" plays. "But when we do, let's do it safely."

"Buds are back," it concludes.

"It's saying this is a moment for us to celebrate," said Monica Rustgi, U.S. vice president of marketing at Budweiser. "It's been four months when everyone has been doing their part appropriately to stabilize the curve."

It was simultaneously imperative for Budweiser to deliver a safety message, Ms. Rustgi said.

Even ads that don't mention responsibility are often part of larger efforts that emphasize social distancing and other measures. In addition to its "Now Open" ad, the Las Vegas Convention and Visitors Authority began a campaign called "#VegasSmart" that urges wearing a mask and other steps.

"The trick now is what classic advertising is about, which is mining how we can be relevant to the times without necessarily being overt about Covid as the condition," said Aki Spicer, chief strategy officer at the Chicago office of ad agency Leo Burnett, part of Publicis Groupe SA. "That's the next layer of evolved advertising right now."

Mr. Spicer said he is encouraging his teams to lean into the optimism some consumers feel -- "not false goofy optimism, but the hope of the times."

Marketers need to listen to consumers more closely than before, said Janet Balis, global media and entertainment advisory leader at Ernst & Young LLP. The unity that largely marked the early stage of the pandemic has given way to divisions around issues such as the pace of reopening, said Ms. Balis, who also leads EY's CMO practice.

"Brands need to be even more careful than at the beginning of the crisis, " she said.

Write to Nat Ives at nat.ives@wsj.com