Covid-19 hospitalizations this past week were higher than ever
(CNN) -- More people traveled through US airports on Sunday than any other day this pandemic, setting the stage for waves of new infections across the country.
Over 1.28 million people passed through security checkpoints, the Transportation Security Administration said.
At the same time, more Americans were hospitalized this past week than any other week of the pandemic, according to the Covid Tracking Project.
Six states set records Sunday for the most Covid-19 patients hospitalized: Alabama, California, Georgia, Mississippi, North Carolina and South Carolina.
Doctors say mass holiday travel will lead to even more patients -- a huge problem because many hospitals are already beyond capacity.
"It's really frustrating, because if you look at the data over the last 10 days, it actually started to show some signs of light," said Dr. Jonathan Reiner, professor of medicine at George Washington University.
"Places like the Midwest, with a drop in the number of cases. Even in the Northeast. US positivity rate dropped from about 12% down to about 10%. Those are really tangible signs of a slowing of the crisis. And now there almost certainly will be another spike."
And unlike previous holidays, the Christmas-New Year combo stretches an entire week.
"We know that after every major holiday, that there was a spike in the number of cases," emergency medicine physician Dr. Leana Wen said.
"We saw this after Memorial Day, after Fourth of July, after Labor Day. And those holidays were relatively short in comparison to Christmas and New Year's."
On top of that, the weather is much colder now -- meaning more indoor gatherings and increased risk of aerosolized spread.
Patients are taking up more and more ICU beds
ICUs are often associated with heart attacks and car accidents, but a growing number of ICU beds are occupied by Covid-19 patients.
This past week, about 40% of all ICU patients in the US had Covid-19, according to a CNN analysis of data published Monday by the US Department of Health and Human Services.
That's up from 16% in late September; 22% in late October; and 35% in late November.
And more hospitalizations inevitably precede more deaths.
More than 63,000 Americans have already died so far this month -- the most of any month since the pandemic began, according to Johns Hopkins University.
In just 11 months, more than 333,000 people have died from Covid-19. That means more than 1 in 1,000 Americans have died from coronavirus.
One hospital in California may soon have to ration the limited number of ICU beds and treatment equipment, meaning some people will get treatment and others won't, infectious disease specialist Dr. Kimberly Shriner said.
At this rate, Huntington Memorial Hospital in Pasadena is preparing for the "ultimate triage" she said.
And since most Americans can't get vaccinated until well into next year, the US faces a "surge upon a surge" following holiday travel, said Dr. Anthony Fauci, director of the National Institutes of Health.
"As we get into the next few weeks," he said, "it might actually get worse."
New travel requirements go into effect Monday
As more countries detect the highly contagious strain of coronavirus first spotted in the UK, the US Centers for Disease Control and Prevention announced new testing requirements for travelers arriving from the UK.
The new rules go into effect Monday. Passengers must have had a negative PCR or antigen test within 72 hours of boarding a flight from the UK to the US, along with documentation of their lab results.
Airlines will be required to confirm the test prior to the flight.
All viruses mutate over time, and the novel coronavirus has mutated before. But scientists advising the UK government estimated this strain could be up to 70% more effective at spreading than others.
The companies behind the first two vaccines to gain emergency authorization in the US -- Pfizer/BioNTech and Moderna -- are testing their vaccines to confirm whether they're effective against the new strain.
The vaccine rollout is slower than expected
About 2.1 million Covid-19 vaccine doses have been administered in the US, according to the CDC. More than 11.4 million doses have been distributed.
Those numbers now include both the Pfizer/BioNTech and Moderna Covid-19 vaccines. And while there are lags in data reporting, federal officials had previously said they were working to distribute 20 million doses by the end of the year.
Asked about the apparent slow rollout of vaccines, Fauci said large, comprehensive vaccine programs with a new vaccine start slow before gaining momentum.
"I'm pretty confident that as we gain more and more momentum, as we transition from December to January and then February to March, I believe we will catch up with the projection," he said.
Dr. Esther Choo, a professor of emergency medicine at Oregon Health & Science University, said vaccine distribution is "just a very complicated thing."
"At every step, there's complexity and there's possibility for delay, whether it's individual state planning, allocation, training, supply of vaccine, storage ... there (are) just so many factors at this stage," Choo said.
"We need to be prepared for the fact that it is going to be a slow rollout in many places and that it will not change our behaviors or necessarily the trajectory of the pandemic in this country in the short term," Choo said.
With vaccines likely not widely available until the summer, experts have urged Americans not to let their guard down. That means continuing to wear masks, washing hands frequently, and social distancing.
Why herd immunity is a moving target
For the US to achieve herd immunity through vaccination, 70% to 85% of the population would need to get vaccinated to it, Fauci said.
"The range is going to be somewhere between 70 and 85%," Fauci said Sunday.
He said the reason he initially said 70% to 75% and then increased the high-end to 85% "was really based on calculations and pure extrapolations from measles."
"We have to realize that we have to be humble and realize what we don't know," he said. "These are pure estimates and the calculations that I made, 70 to 75%, it's a range."
The measles vaccine is about 98% effective, Fauci said. When less than 90% of the population is vaccinated against measles, there starts to be a breakthrough against herd immunity, and people start to get infected.
"So I made a calculation that Covid-19, SARS-CoV-2, is not as nearly as transmissible as measles," Fauci said.
"Measles is the most transmissible infection you can imagine. So I would imagine that you would need something a little bit less than the 90%, that's where I got to the 85."
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