Coronavirus live updates: Lockdowns lead to shocking drop in air pollution; 3D printers make swabs

This is CNBC’s live blog covering all the latest news on the coronavirus outbreak. All times below are in Eastern time. This blog will be updated throughout the day as the news breaks. 

• Global cases: More than 2.5 million
• Global deaths: At least 178,371
• US cases: More than 825,300
• US deaths: At least 45,075

The data above was compiled by Johns Hopkins University.

New York City will need to run “hundreds of thousands” of coronavirus tests a day before officials can to ease social distancing guidelines, Mayor Bill de Blasio said.

“To get to low-level transmission and to hold onto it, you need a huge amount of testing. Not just tens of thousands of tests per day but as many as hundreds of thousands tests per day for a city of 8.6 million people,” de Blasio said at a press conference.

There is still widespread transmission throughout the city, meaning that health officials aren’t able to trace the origin of most Covid-19 cases and residents need to maintain social distancing to contain the outbreak, de Blasio said. To get to the next phase of the outbreak, low-level transmission, the city needs greater testing so that it can isolate individual cases faster and trace and isolate the patient’s contacts, de Blasio said. —Noah Higgins-Dunn, Jasmine Kim

IQAir, a Swiss-based air quality technology company, compared measurements of the world’s deadliest air pollutants before and during the Covid-19 outbreak in 10 major cities across the globe.

The findings, published Wednesday, revealed a “drastic drop” in air pollution for almost all of the cities under lockdown when compared to the same period a year earlier.

India’s New Delhi recorded a 60% drop in air pollution compared to 2019 levels, South Korea’s Seoul registered a 54% decline over the same period, while the drop in China’s Wuhan came in at 44%. See how lockdowns have affected other major cities here. —Sam Meredith

Years of private funding flowing into young and growing space companies has ground to a halt during the coronavirus pandemic, in what one firm describes as a “culling” of space companies backed by venture capital.

Investment in private space companies had seen a golden age in recent years, including a record nearly $6 billion last year. But that’s ended due to the coming “Covid-19-induced recession,” a report by Quilty Analytics on Monday said, in a shakeout the firm expects will last about two years. Quilty Analytics is a boutique research and investment firm focused on the satellite and broader space industry.

“When the dust settles, we believe that a bit less than half of the companies listed on our Top Venture Companies list below will remain healthy and operational (or alternatively, will have completed a decent exit event),” analysts Chris Quilty and Justin Cadman said in the report. —Michael Sheetz

AT&T‘s first-quarter revenue fell short of Wall Street expectations and the company pulled its annual forecast on Wednesday, as the impact of the coronavirus outbreak overshadowed a strong growth in monthly phone subscribers.

The U.S. media and telecommunications giant said the pandemic reduced earnings by 5 cents per share. Advertising sales, which was severely hit due to the postponement of live sports such as March Madness, and lower wireless equipment sales led to a $600 million decline in revenue, AT&T reported.

The company said it had limited visibility for the rest of the year, but added that it had enough free cash flow to pay dividends and make debt payments. —Reuters

Stocks rose for the first time in three days on Wednesday as crude prices tried to stabilize after a record plunge.

The Dow Jones Industrial Average jumped 450 points, or 1.9%. The S&P 500 climbed 2.1% while the Nasdaq Composite advanced 2.2%.

The West Texas Intermediate contract for June was up 12.3%, trading at $12.99 per barrel, after an earlier decline. Brent futures, meanwhile, were up 5.9% at $20.48 per barrel, recovering from a sharp overnight drop. —Fred Imbert, Maggie Fitzgerald 

Some health experts say the U.S. may have to do millions of tests — as many as 20 million to 30 million — per day.

That will take many more nasal swabs — a simple, but critical tool that’s in short supply.

A group of hospitals and companies are turning to 3D printers to ramp up production. Researchers at University of South Florida Health, a Tampa-based medical school, and Northwell Health, New York’s largest health-care provider, teamed up to develop a 3D-printed swab that they can make at hospitals. They tested the design and produced the swabs with Formlabs, a 3D printing company that plans to make hundreds of thousands of them.

The swabs are used for the most common type of Covid-19 test. The stick, which has a bristled end, goes deep into a person’s nasal cavity and collects a sample that’s tested for the coronavirus. 

The thousands of additional swabs could help alleviate some of the supply chain struggles that have slowed efforts for widespread testing. —Melissa Repko

Macy’s is taking extreme measures to avoid dire outcomes like bankruptcy and will try to raise billions in debt to weather the pandemic crisis, according to people familiar with the matter.

The country’s largest department store is looking at raising as much as $5 billion in debt, the people said. It will seek to use its inventory as collateral to raise $3 billion and real estate to raise $1 billion to $2 billion, they said. It is not planning to pledge its prime Herald Square location in New York as part of the deal, one of the people said.

The retailer earlier this year retained investment bank Lazard to help shore up its balance sheet. —Lauren Hirsch 

Delta Air Lines‘ on Wednesday posted a pretax loss of $607 million for the first quarter and issued a bleak forecast for this spring as the coronavirus saps travel demand.

The Atlanta-based carrier’s revenues plunged 18% in the quarter to $8.6 billion. CEO Ed Bastian said second-quarter revenue will likely fall 90% on the year.

The airline spent the quarter shoring up cash and slashing expenses to combat the sharp drop in revenue. It burned through $100 million a day at the end of March, a rate it expects to halve by the end of the second quarter.

Airlines are among the industries hit hardest by coronavirus and harsh measures to stop it from spreading, like stay-at-home orders. Carriers including Delta were granted a portion of $25 billion in government grants and loans dedicated to paying employees through Sept. 30. —Leslie Josephs

Nasdaq CEO Adena Friedman told CNBC on Wednesday that taking employees’ temperatures will probably be part of their coronavirus plan to return workers to company offices around the world.

“We will likely ask them a series of questions, take their temperature and do other things to make sure we can manage our employees successfully,” Friedman said on CNBC’s “Squawk Box.”

Nasdaq has offices in 30 countries. Friedman said that decisions on returning employees to those locations, including in New York City, will be dependent on the curve of the virus in each specific place.

The first criteria in sending workers back will be whether the number of new Covid-19 cases is on the decline, Friedman said, adding Nasdaq will also evaluate whether local hospitals are “able to manage through the case load they have.” —Kevin Stankiewicz 

Oil jumped more than 10% on Wednesday, reversing steep losses after a volatile overnight trading session which saw international benchmark Brent crude fall to its lowest level in more than 20 years.

West Texas Intermediate, the U.S. benchmark, rose $1.73, or 14%, to trade at $13.19 per barrel. Earlier in the session WTI had traded as low as $10.26. Brent crude traded 7%, or $1.37, higher at $20.68, after previously breaking below $16. —Sam Meredith, Pippa Stevens, Eustance Huang 

Serology tests, which can detect the presence of coronavirus antibodies and identify whether someone has already been exposed to Covid-19, have a “very high false positive rate,” former Food and Drug Administration Commissioner Scott Gottlieb told CNBC. 

Earlier this week, University of Southern California professor Neeraj Sood, who led a large antibody study in Los Angeles county, claimed the tests he used were very accurate. However, Gottlieb was cautious about the antibody tests.

“They shouldn’t be using these tests to make individual decisions for individual patients,” Gottlieb said. “They’re good for population-level studies and they’re good maybe in certain professions where there’s a very high exposure to coronavirus, but for the general population an antibody test probably isn’t that helpful.” —Will Feuer

Disclosure: Scott Gottlieb is a CNBC contributor and is a member of the boards of Pfizer and biotech company Illumina.

Its neighbors closed borders, schools, bars and businesses as the coronavirus pandemic swept through Europe, but Sweden went against the grain by keeping public life as unrestricted as possible.

The strategy has been controversial. The country tried to slow the spread of the virus while allowing some exposure to it, aiming to build immunity among the general population while protecting high-risk groups like the elderly. Some health experts likened it to playing Russian roulette with public health.

But now, the country’s chief epidemiologist said the strategy appears to be working and that “herd immunity” could be reached in the capital Stockholm in a matter of weeks.

The number of cases in Sweden is almost double that in neighboring Denmark (it has 8,108 cases and has reported 370 deaths) and Finland (with just over 4,000 cases and 141 deaths) that imposed strict lockdown measures. Since their populations are each about 5 million — half of Sweden’s — the rates are about the same, although the comparison could be skewed by testing numbers in each country. But Sweden’s 1,937 deaths is far higher in number and proportionally to Denmark’s 370 and Finland’s 141. —Holly Ellyatt

The coronavirus pandemic is expected to drive carbon dioxide emissions down 6% this year, the head of the World Meteorological Organization said, in what would be the biggest yearly drop since World War II.

“This crisis has had an impact on the emissions of greenhouse gases,” WMO Secretary-General Petteri Taalas told a virtual briefing in Geneva. “We estimate that there is going to be a 6% drop in carbon emissions this year because of the lack of emissions from transportation and industrial energy production.” —Reuters

The number of confirmed infections has passed 10,000 in Poland. The somber milestone comes as the country prepares for a presidential election on May 10.  Poland was among the first countries in Europe to impose lockdown measures to try to contain the virus.

A deputy health minister said the rise of new infections “had been contained to a degree,” Reuters reported.

 “We are still seeing increases,” ministry spokesman Wojciech Andrusiewicz told reporters. “What we can achieve is to level them off. If it wasn’t for the restrictions, we could be seeing 30,000 to 40,000 people infected.” —Holly Ellyatt

Spain’s death toll from has risen to 21,717 from 21,282 the previous day, a rise of 435 deaths, the country’s health ministry said.

Spain reported 430 deaths on Tuesday, higher than the 399 deaths reported Monday. The total number of cases has reached 208,389, up 4,211 from the day before. —Holly Ellyatt

India has ordered a pause in testing for antibodies because of concerns over the accuracy of the results, health officials said Wednesday, Reuters reported.

Earlier in April, India’s health authorities approved blood tests for coronavirus antibodies as a faster way to bolster the screening effort, and they ordered more than a half-billion testing kits from China.

But the chief of epidemiology at the Indian Council of Medical Research said he has asked health authorities to temporarily stop the tests for antibodies because of conflicting results. India has almost 20,000 confirmed cases of Covid-19. —Holly Ellyatt

Russia and President Vladimir Putin are facing a “very problematic” situation as the coronavirus outbreak accelerates in the country, the Kremlin’s spokesman told CNBC on Tuesday.

“It’s a huge challenge and a huge danger for every nation in the world. It’s not only about Putin or about Russia, every country is facing this challenge and it’s quite unprecedented, we have never faced it before,” Dmitry Peskov, Putin’s spokesman, told CNBC Tuesday.

He noted that it was the first major international pandemic situation that anyone — including Putin — had faced.

Russia confirmed 5,236 new cases on Wednesday, bringing the country’s official tally to 57,999. Nonetheless, the official death toll remains strikingly low — 513 people. —Holly Ellyatt

Read CNBC’s coverage from CNBC’s Asia-Pacific and Europe teams overnight here: India halts antibody tests; Poland’s total cases exceed 10,000