What the Delta variant could mean for Covid-19 in the United States

(CNN)A coronavirus variant first spotted in India is poised to become the dominant one in the United States, where infectious disease modelers say it could cause a “resurgence” of Covid-19 later this year.

And it may already account for 1 in every 5 infections nationwide, experts say.
The Delta variant, as it’s now called, has swept across the UK, all but replacing the Alpha variant first identified there late last year.
“This is the most transmissible of all the variants that we’ve seen,” Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, told CNN’s Ana Cabrera Monday.
“We saw what happened in the UK, where it overtook the entire nation. So I’m worried that’s going to happen in the US,” he said.
Dr. Rochelle Walensky, director of the US Centers for Disease Control and Prevention, told CNN last week she anticipates Delta will become “the predominant variant in the months ahead.”
And that could be a few weeks — not months — away, according to William Lee, vice president of science at Helix, a company whose Covid-19 tests have helped track a number of variants.
In the two weeks leading up to June 5, CDC estimates that Delta was responsible for nearly 10% of US infections. And now, Hotez, Lee, and the nation’s top infectious disease physician, Dr. Anthony Fauci, say it accounts for roughly a fifth of cases.
“As of a couple of days ago, 20.6% of the isolates are Delta,” Fauci said at a White House briefing Tuesday, referring to the two weeks leading up to June 19. This number has roughly doubled every two weeks, he added.
“It’s so transmissible that, unless your vaccination rates are high enough, you will still have outbreaks,” said Lee.
A more transmissible variant like Delta also raises the bar for what percent of a population has to be vaccinated “to reach this mythical herd immunity,” he explained.
“More worrisome is that we know that there are pockets of unvaccinated people,” he added. “And so I would be worried about Delta spreading very quickly in those pockets.”

Predicting the future

Infectious disease modelers are showing how a variant like Delta could make a Covid-19 comeback later this year.
Faced with a more transmissible variant, “it looks like we do see a resurgence late in the summer, or in the early fall,” said Justin Lessler, an epidemiologist with the Johns Hopkins Bloomberg School of Public Health.
Lessler has been working with contributors from a dozen other institutions on the Covid-19 Scenario Modeling Hub to forecast the pandemic.

The most recent model finds that a Delta-like variant that’s assumed to be 60% more transmissible than Alpha, coupled with 75% of eligible Americans getting vaccinated, can result in Covid-19 bouncing back from summer lows to cause more than 3,000 deaths per week at various points during the fall and winter — coinciding with children returning to school and weather that pushes people back indoors.
That’s about 1,000 more Covid-19 deaths than the US has seen over the past week, though still far below the peak of 24,000 deaths during the second week of January.
But according to the model, getting 86% of eligible Americans vaccinated — meaning, those 12 and up — could avert more than 10,000 cumulative deaths by late November.
Currently, 62.5% of Americans 12 and up have gotten at least one dose of a vaccine, according to CDC. At the current pace, the country would hit 75% in September and 86% in November. However, the pace of vaccination has slowed in recent weeks.
Lessler said that Covid-19 resurgences wouldn’t be experienced uniformly all over the country: “It’s the states that have lower vaccination rates, and a lower projected vaccination rate, that are really driving those resurgences.”
At the White House briefing Tuesday, Fauci called Delta the country’s “greatest threat” in its fight against the coronavirus.
But it’s a preventable threat, he added, and one that’s unlikely to reach the level of earlier peaks. Instead, “you could see localized surges,” he said. “All of that is totally and completely avoidable by getting vaccinated.”
Research on Delta in the UK has shown high levels of protection from two doses of the vaccines used there, with effectiveness against hospitalization exceeding 90% for both Delta and Alpha, according to Public Health England.
Dr. David Rubin, director of PolicyLab at Children’s Hospital of Philadelphia, has also seen trends of increasing cases, hospitalizations and deaths in areas of lower vaccination.
Rubin said his team is increasingly focused on hospitalizations and emergency room data to see how the pandemic plays out because, as fewer people get tested, the number of cases is becoming a less reliable marker.
In areas with lower vaccination rates, they noted a slower rate of decline in hospitalizations. Rubin pointed to the state of New York, where about 52% of the population is fully vaccinated, and where the rate of new hospital admissions has been steadily declining. Meanwhile, in a state like Missouri, where just 38% are fully vaccinated, the hospitalization rate is not only higher but has shown an increasing trend since mid-May, according to CDC data.
While it may feel like the country has turned a corner, Rubin warned “the pandemic hasn’t ended.”
Polls such as the Kaiser Family Foundation’s have shown that about 1 in 5 adults say they won’t get vaccinated, or will only do so if required. But that number is higher among certain groups — like Republicans, White evangelical Christians, younger age groups and people who live in rural areas.

Delta’s trajectory in the US

While experts agree that Delta poses a greater threat to unvaccinated populations, it’s not a foregone conclusion it will follow the exact same trajectory in the US as it did in the UK, Helix’s Lee said.
In a preprint that has not yet been peer-reviewed, Lee and his colleagues describe how the US outbreak has unfolded somewhat differently:
In the US, Covid-19 cases caused by the Alpha variant (also known as B.1.1.7) grew to 70% in April but plateaued there — at a much lower level than it did in the UK.
It’s hard to know exactly why, Lee said. It may have something to do with the diverse set of policies that could impact the spread of the virus — including public health measures and the vaccine rollout in the US.
Even so, from late April to mid-June, the Alpha variant fell from 70% to 42% of Covid-19 cases. And it’s not just Delta that appears to be responsible, but also another variant of concern found in Brazil  — known as P.1 or Gamma.

Great Barrier Reef world heritage site should be listed as ‘in danger’

Australian government ‘stunned’ by recommendation and will strongly oppose draft decision, environment minister Sussan Ley says

The Great Barrier Reef should be placed on to a list of world heritage sites that are “in danger”, according to a recommendation from UN officials that urges Australia to take “accelerated action at all possible levels” on climate change.

The United Nations Educational, Scientific and Cultural Organization says the world’s biggest coral reef system should be placed on the list at the world heritage committee meeting next month.

The recommendation has sparked a flurry of activity from the Australian government, with the environment minister, Sussan Ley, saying she had already joined the foreign affairs minister, Marise Payne, in a call to Unesco’s director general, Audrey Azoulay.

If the committee followed the recommendation, experts said it would be the first time a natural world heritage site has been placed on the “in danger” list mainly because of impacts from the climate crisis.

Global heating caused by fossil fuel burning has driven ocean temperatures higher, leading to three mass bleaching events on the 2,300km reef since the last time it was assessed by the committee in 2015.

Ley said the government would “strongly oppose” the recommendation, claiming officials had been “stunned” by what she described as a “backflip on previous assurances” by UN officials the step would not be taken this year.

World heritage sites are global icons and “in danger” listings are usually recommended after effects from armed conflict and war, pollution, poaching and uncontrolled urbanisation.

The Unesco report says a revision of Australia’s key reef policy – the reef 2050 plan – should “fully incorporate” conclusions from a major government review that “accelerated action at all possible levels is required to address the threat from climate change”.

The report said despite efforts and achievements by the state and federal governments, key targets on improving water quality had not been met.

“The plan requires stronger and clearer commitments, in particular towards urgently countering the effects of climate change, but also towards accelerating water quality improvement and land management measures,” it said.

Ley said the recommendation followed “a complete subversion of normal process”. She said officials had been reassured a week ago that Unesco would not be recommending the reef be placed on the “in danger” list.

The government suspects China may have played a role in the latest recommendation. It chairs the World Heritage Committee and will host a meeting on 16 July at which the draft recommendation will be considered.

Ley said climate change was the biggest threat to the reef but the world heritage committee was “not the forum” to “make a point” about climate change.

“This decision was flawed and clearly there was politics behind it, and that has subverted the proper process. For the World Heritage committee not to foreshadow this listing is appalling,” she told reporters on Tuesday.

She said there were more than 80 world heritage properties that Unesco had identified as under threat from climate change. The government may have understood if the body decided to list all of them as “in danger”, but it had singled out the reef, she said.

“When procedures are not followed and the process is turned on its head and the assurances my officials received have all been upended at the last minute, what else can you conclude … that this is politics.”

Ley had called Azoulay overnight, saying: “I made it clear that we will contest this flawed approach, one that has been taken without adequate consultation.

“This sends a poor signal to those nations who are not making the investments in reef protection that we are making.”

It is the second time the reef has faced the threat of an in danger listing. The last time, in 2015, the government embarked on a successful lobbying effort to pressure the 21-country committee.

Unesco is also recommending that a monitoring mission be launched to develop “corrective measures”, asking the Queensland and federal governments to submit a report by February 2022 outlining new steps to protect the reef.

The conservation groups WWF-Australia and the Australian Marine Conservation Society have lobbied members of the committee before the reef decision, asking them to pressure Australia to take stronger action on cutting greenhouse gas emissions.

A consultant to the AMCS, Imogen Zethoven, said Australia’s climate policies were “more consistent with a 2.5-3.0C rise in global average temperature – a level that would destroy the Great Barrier Reef and all the world’s coral reefs.”

She said the Australian government’s inaction had led the reef to the brink of the “in danger” listing.

Richard Leck, head of oceans at WWF-Australia, said Australians would be shocked by the Unesco recommendation but it was “a powerful message” that the government needed to “lift its game” on climate change.

Australia’s greenhouse gas emissions targets have not changed since 2015 and the prime minister, Scott Morrison, has resisted international pressure to adopt a firm net zero target by 2050.

Assoc Prof Scott Heron, of James Cook University, has led a study on the effects of climate change on world heritage reef sites. He said the recommendation was a “surprise” but “also not completely unexpected.”

“These cards have been stacking up over the past years,” he said.

The Labor leader, Anthony Albanese, said the threat of an “in danger” listing for the reef came as the return of Barnaby Joyce as Nationals’ leader made the government less likely to commit to a target of net zero greenhouse gas emissions by 2050.

“The whole of the G7, every state and territory government, every major business in Australia, the Business Council of Australia, the National Farmers’ Federation have all committed to it,” he said. “The election of Barnaby Joyce just sends the wrong message.”

The Greens leader, Adam Bandt, said the government had to choose between coal or the reef.

“You can’t have both,” he said. “If the world heats up over 1.5C [compared with pre-industrial levels], the reef will die. The only party in Australia with climate targets in line with 1.5C is the Greens.”