Covering COVID-19 is a daily Poynter briefing of story ideas about the coronavirus and other timely topics for journalists, written by senior faculty Al Tompkins. Sign up here to have it delivered to your inbox every weekday morning.

Lawyers worked through the weekend mounting their newest challenge to the Biden administration’s COVID-19 vaccine mandate for employers with 100 or more employees. The 6th U.S. Circuit Court of Appeals ruled late Friday that the mandate to be enforced by Occupational Safety and Health Administration is valid, but other Biden mandates are on the legal ropes.

A mandate that all federal contractors require employees to be vaccinated or tested and a mandate requiring all health care and nursing home workers employed by companies that get federal dollars (which accounts for nearly all of them) to be vaccinated were both blocked by courts.

You would be forgiven if all of this is confusing since the 6th Circuit Court’s ruling overturned a ruling from the 5th U.S. Circuit Court of Appeals, which said the emergency rule was outside of OSHA’s authority.

The lawsuits involved states, including Kentucky, Florida and Indiana, plus groups like the National Homebuilders Association as well as labor unions and businesses.

The court reasoned that in years past, OSHA set safety standards to protect against HIV and hepatitis. And OSHA’s concerns do not stop with the workplace; it also looks for workplace hazards that could go home with the worker, such as hazardous substances that get on their clothes. So, the court said there is no doubt OSHA has the authority to regulate infectious diseases, too.

The ruling concluded:

The responsibility the Act imposes on OSHA to protect the safety and health of employees, moreover, is hardly limited to “hard hats and safety goggles.” OSHA has wide discretion to form and implement the best possible solution to ensure the health and safety of all workers and has historically exercised that discretion.

Having been charged by the Act with creating such health-based standards, it makes sense that OSHA’s authority contemplates the use of medical exams and vaccinations as tools in its arsenal.

The next stop will almost certainly be the U.S. Supreme Court.

How to wrap your head around exponential growth of new COVID-19 cases

In the United Kingdom and Denmark — and undoubtedly soon in the United States — new COVID-19 cases are doubling every four days. At this rate, your holiday plans may be in peril. The omicron variant is spreading fast, but so is the delta variant that has been in the U.S. since spring.

Former Biden administration COVID-19 adviser Michael Osterholm said, “I think in the next three to eight weeks, we’re going to see millions of Americans are going to be infected with this virus, and that will be overlaid on top of delta, and we’re not yet sure exactly how that’s going to work out.” Dr. Anthony Fauci said the omicron variant will be the dominant coronavirus variant in the U.S. within a few weeks.

And while two doses of the Pfizer or Moderna vaccines protect against severe illness caused by omicron, they are not proving to stop infection. However, researchers believe that two shots plus a booster shot are about 70% effective against symptomatic infection. The current monoclonal antibodies available have not proven that they can prevent omicron infection, either. They have proven somewhat but not always effective against the delta variant.

Some good news might be on the way within weeks in the form of Paxlovid, a Pfizer pill that has proven to be effective in keeping people out of the hospital. But, again, it does not prevent infection.

Exponential growth is way different from steady growth. It is an explosive growth. Let’s be sure we understand what that means. We turn to Gary Cornell at Slate:

Exponential growth means that the amount of growth during the next time period depends on the amount of stuff there is now (by “stuff” we might mean virus, or maybe miles, if you have a very special kind of car). This is a little hard to wrap one’s head around, so let’s consider an (apocryphal, if classic) story about a chess board, recounted in a blog post on NPR.

It starts with a craftsman presenting a chessboard to a king, and then:

He told the king: “Your Highness, I don’t want money for this. Or jewels. All I want is a little rice.”

“Hmm,” thought the king, who was a con man himself.

“I’ve got rice. How much rice?”

“All I want,” said the craftsman, “is for you to put a single grain of rice on the first square, two grains on the second, four on the third, eight on the fourth, and so on and so on and so on, for the full 64 squares.

“I can do that,” said the king, not thinking. And he ordered his granary to pay the man for the chessboard

How much rice would the craftsman get with this deal?

Well, it is 1+ 2 + 4 +8 + 16 + 32 + 64 … doing this out for 64 times in order to fill all 64 squares of the chessboard. Which (trust me) works out to 18,446,744,073,709,551,615 grains of rice.

That’s more than 18 quintillion grains of rice, which would roughly cover the planet and would be the world’s output of rice for about 1,000 years. (In this telling, the king comes out ahead by telling the craftsman he needs to count the rice himself — a task that would take many times the age of the universe.)

As Cornell points out, if it was just a linear increase (three grains in the first square, six grains in the second square and so on) you would end up with less than five ounces of rice at the end.

Put it on a chart and it looks like this, with the red line being the linear growth and the green chart representing exponential growth:

(Wikimedia Commons)

The British chart does not look like that yet, but the straight-up nature of the new cases line is stunning similar to the exponential line I just showed you.

(Johns Hopkins)

And in New York City, a similar graphic from Mayor Bill de Blasio’s top medical adviser Dr. Jay Varma:

Um, we’ve never seen this before in #NYC.

Test positivity doubling in three days

12/9 – 3.9%
12/10 – 4.2%
12/11 – 6.4%
12/12 – 7.8%

Note: Test % is only for PCR & NYC does more per capita daily than most places ~67K PCR/day + 19K [reported] antigen over past few days (1/2) pic.twitter.com/PhxsZq55jn

— Jay Varma (@DrJayVarma) December 16, 2021

Should you cancel holiday travel?

Travelers wear masks as they wait in a line for a TSA security check, Friday, Dec. 10, 2021, at Seattle-Tacoma International Airport in Seattle. (AP Photo/Ted S. Warren)

Jeff Zients, the White House coronavirus coordinator, said, “For the unvaccinated, you’re looking at a winter of severe illness and death for yourselves, your families and the hospitals you may soon overwhelm.”

The Washington Post asked a half dozen public health officials for their advice about whether you should cancel travel plans this week. Daniel Rhoads, section head of microbiology at the Cleveland Clinic, advises:

• Before traveling internationally-be mindful that each country’s rules are subject to change at a moment’s notice.
• “Things like travel insurance and changeable tickets — all of those matter,” he says.
• If you’re concerned about the financial toll of getting stuck abroad longer than planned because of a coronavirus infection, “you should probably stick to domestic travel.”

Anthony J. Santella, professor of health administration and policy at the University of New Haven, says:

• For vaccinated travelers who are following precautions and are not at high risk for severe coronavirus infection, getting on a plane or train isn’t a huge concern.
• What’s more important is what happens on your trip.
• As you assess your risk tolerance, Santella says travelers can consider questions like: “What are you doing on the other side? Where are you going? Who are you interacting with?”

Ohio State University chief quality and patient safety officer Iahn Gonsenhauser warns, “Just about everyone should be prepared to get infected during this wave.”

Explaining ‘test to stay’

Until now, the Centers for Disease Control and Prevention’s advice has been that if a child is exposed to COVID-19, they should quarantine. That changed and now the CDC is saying unvaccinated children no longer have to quarantine and can stay in class if they test negative repeatedly.

The concept is called “test to stay” and until now, the CDC had not endorsed the idea, even though some school systems have.

The recommendation is based on these studies of Los Angeles schools where the California Department of Health put test to stay into place in July.

The strategy enabled unvaccinated students, exposed in school to a person infected with the virus that causes COVID-19, to remain in school while under quarantine:

if both the infected person and the exposed person wore masks correctly and consistently throughout the exposure. To stay in school during the quarantine period, the exposed student must remain asymptomatic, wear a mask at school, and undergo twice weekly testing for SARS-CoV-2.

From mid-September to the end of October, researchers evaluated the concept across 78 schools, some of which used it and some which insisted on quarantines. The result, researchers say, is no significant difference in the spread of the virus. But schools that required quarantining lost 92,455 in-person school days while the test to stay schools lost none. The researchers said:

Preliminary data from LAC suggest that a school-based TTS strategy does not increase school transmission of SARS-CoV-2, and might greatly reduce loss of in-person school days; however, TTS might have barriers to implementation and require resources that are not available for some schools.

A second newly released CDC study, this one from Lake County, Illinois, found similar results to the Los Angeles study. The researchers there concluded:

Assuming a maximum of 8 missed school days for every 10-day quarantine period, up to 8,152 in-person learning days were saved among TTS participants. Implementation of TTS with other concurrent prevention strategies, including masking and physical distancing, limited further spread of SARS-CoV-2 within K–12 schools and allowed students to safely sustain in-person learning. Although vaccination remains the leading public health recommendation to protect against COVID-19 for those aged ≥5 years, schools might consider TTS as an option for allowing close contacts who are not fully vaccinated to remain in the classroom as an alternative to home quarantine.

While test to stay is now the recommended policy for schools, there are issues that school systems will have to resolve about who will administer the tests and whether there are enough tests available.

New Orleans schools require vaccines for all 5+

Feb. 1 is the deadline for all New Orleans school children to be vaccinated against COVID-19. Mayor LaToya Cantrell said that beginning Jan. 3, children ages 5 to 11 will have to show proof of vaccination or a negative test to enter restaurants and other businesses. Families can apply to opt out of the new rules for medical and/or religious or personal reasons.

Anybody over 12 years old must show proof of vaccination to get into public places. New cases, which had been flat in New Orleans, have nearly doubled recently.

How does ‘test to stay’ apply beyond schools?

CDC director Dr. Rochelle Walensky was not ready to say that test to stay had any application outside of school … yet. If more research found it to be applicable in other settings, for example at work, it could change how businesses insist on quarantine for employees who have been exposed. It could also dramatically increase workplace testing.

Small setback for Pfizer vaccine for young children

Pfizer says the low dose two-shot vaccine it has been testing for children aged 6 months to 5 years didn’t produce enough antibodies to be effective, so the company says it will see if a third low-dose shot produces the protection the researchers are shooting for. The good news is that the drug trials did not turn up safety concerns in the young children who got the shots. Pfizer says the drug trials for young children involved “4,500 children ages 6 months to under 12 years of age in the United States, Finland, Poland, and Spain from more than 90 clinical trial sites.”

Covering COVID-19 is on a limited schedule until Jan. 3. We’ll be back next Monday with a new edition. Are you subscribed? Sign up here to get it delivered right to your inbox.