(Reuters) - From Rupert Murdoch’s News UK to McClatchy’s chain of local newspapers across the United States, news publishers are attracting record numbers of readers as people in lockdown seek information about the coronavirus pandemic.

FILE PHOTO: An uncollected Wall Street Journal newspaper sits on a stoop along a nearly deserted Wall Street in lower Manhattan during the outbreak of the coronavirus disease (COVID-19) in New York City, New York, U.S., April 3, 2020. REUTERS/Mike Segar/File Photo

Yet advertising revenue has plummeted for many publishers as companies slash marketing budgets and prove reluctant to buy ads against coronavirus coverage for fear of tarnishing their brand.

Forecasts for global advertising growth this year have been revised down by $20 billion since March 12, according to market research firm eMarketer. It estimates ad spending growth of just 8.4% in China, where the outbreak began, the slowest since 2011.

Total local advertising in the United States could decline by up to 30% this year, or $38 billion, according to media research firm Borrell Associates.

Publishers, advertising agencies and tech firms that help place ads have been trying to persuade brands to rethink, arguing that by eschewing coronavirus coverage, advertisers are losing access to engaged readers.

So far, they appear to have had limited success.

“I can’t say we’ve yet noticed a change,” said Ben Walmsley, commercial director for publishing at News UK, a division of News Corp. “I think change will be relatively slow.”

ViacomCBS-owned VIACA.O CBS News Digital has made some headway with marketers and agencies, said Christy Tanner, its executive vice president and general manager. "But it’s been more slow-going than most of us would like."

The Washington Post and the Atlantic said they also had not seen a shift in behaviour from advertisers who are avoiding pandemic content.

The industry was already suffering from declining advertising revenue. Gannett GCI.N, BuzzFeed, Britain's MailOnline and News Corp Australia have all announced furloughs, pay cuts or other cost-cutting measures.

Damon Reeve, CEO of the Ozone Project, which sells the online ad inventory of a majority of British national titles, said he had heard that advertising was being kept away from up to 60% of editorial content.

A representative for Reuters news organization said the company has also experienced an impact and cited an Internet Advertising Bureau study that showed 70% of advertisers have scaled back ad spending across the industry during this period.

"Factual news coverage on the global pandemic is essential and must be supported," Reuters CEO Michael Friedenberg said on Twitter here on April 2. "It is incumbent upon the ad tech and verification industry to ensure that trusted news from reputable sources about Covid-19 is not blocked by safety filters."

Five of the top U.S. advertising spenders last year - Comcast CMCSA.O, AT&T T.N, Amazon AMZN.O, P&G PG.N and General Motors GM.N - either declined to comment or did not respond to questions about their advertising policies.

“BLACKLIST” BACKLASH

For years, ad tech firms such as DoubleVerify have offered tools for brands to stop ads from appearing on web pages or URLs that include keywords like “shooting” or “murder.” These advertising “blacklists” exploded in usage after the 2016 U.S. election, when brands sought to avoid polarizing news coverage.

“Trump” was the most popular blacklist keyword until “coronavirus” overtook it earlier this year, with more than 3,100 advertisers blocking it as of March, according to ad tech firm Integral Ad Science.

Ad agencies GroupM and Universal McCann have advised clients against blacklisting all coronavirus articles.

“There are stories about death tolls in Italy or the UK which would not be very appropriate to be monetised, but there are stories about communities coming together and we wouldn’t want to block that kind of content,” said Stevan Randjelovic, GroupM’s director of brand safety and digital risk.

Some ad tech companies have urged brands to use tools that help stop ads from appearing on some but not all articles pertaining to coronavirus. Trade groups representing news publishers have also called on the ad community to stop using keyword blocking practices.

“The leaders that need to be speaking out are the advertising brands and the CMOs and I’m starting to see some of that,” said Jason Kint, CEO of trade group Digital Content Next.

The Washington Post sales team is working directly with some advertisers who were previously purchasing ads through automated tools, which might avoid the Post if keyword blocking were applied, said Joy Robins, the newspaper’s chief revenue officer.

“If we’re not able to hand-hold and work directly with brands, there are a lot of unintended consequences with a blanket block,” Robins said.