It has never been possible to know for sure how many people in the United States are sick with COVID-19 at any given time. Instead, we combined all the metrics – the percentage of tests performed that came back positive, the number of new cases reported each day, people who come to the ER with COVID-19 symptoms – to get an estimate. It is like the story of the blind and the elephant: experts can grasp the different information to get a sense of what an outbreak looks like, even when they cannot see it directly.
We saw the same elephant emerge repeatedly in the past year. First, the percentage of tests that give positive results increases. After a slight delay, hospitalizations start to increase and then deaths. But this time, there is a new wrinkle: vaccines. This will change the pattern and make COVID-19 trends in the coming weeks and months more difficult to interpret.
One of the most important data points for tracking the spread of the virus has been the number of people hospitalized with a COVID-19-like disease at any given time. It is a concrete metric. If someone is so sick that he needs to be hospitalized, he is usually in the hospital. Other measures, such as the case rate and the test positivity rate, are meticulous; they vary based on how many people decide to take the test.
“Hospitalizations are our difficult result. Everything else depends a lot on tests, ”says Melissa McPheeters, co-director of the Center for the Improvement of Public Health through Informatics at Vanderbilt University. That’s why we look at hospitalization trends to get a sense of the direction of the pandemic, even when case rates fluctuate.
Now, COVID-19 cases are starting to rise again in the United States. But this time, more than 70 percent of people over 65 in the United States received their first dose of the COVID-19 vaccine. This is the group that, if it catches the virus, is more likely to be hospitalized or die. Now they are vaccinated – and the risk of hospitalization and death is incredibly small.
This could unbalance our normal data patterns. Cases may increase because many states are easing restrictions while most people are not yet vaccinated. But unvaccinated people who get sick may be younger and less likely to be hospitalized.
Our normal method of viewing the elephant would no longer work. It is a good problem to have – less people in the hospital is a wonderful victory. But when case numbers fluctuate and tests increase and decrease, hospitalizations will no longer be a reliable means of protection to clarify what is happening with the pandemic. “I don’t know if we can get such a good sample of what’s going on in the community,” says McPheeters.
This may mean that we need to recalibrate the way we monitor the pandemic. There may be fewer people in the hospital, but we could take a closer look at that group, for example. If many people in an area of the city are hospitalized, or people working in a similar sector, this could be a sign that there is more virus in that particular community – which can help people determine their risk and show employees to where to direct resources. “It’s not just about how many people, it’s Who it’s ending at the hospital, ”says McPheeters.
Last year, people examined COVID-19 metrics to guide decisions about how they should behave – whether to send their children to school, meet with some friends or deliver groceries. Eventually, as more people are vaccinated, new patterns may begin to emerge to guide this analysis. And when the pandemic starts to disappear, we won’t have to look at the COVID-19 numbers so closely. But for now, everything is changing, and we cannot assume that a number means the same thing today as it did in January.
Here’s what else happened this week.
To look for
Unlocking the Covid Code
Take a deep dive into the world of genetic sequencing – and explore how this tool can change public health in a post-pandemic world. (Jon Gertner / The New York Times)
Nobody can find the animal that gave people COVID-19
Groups are looking for the animal that first transmitted the virus that causes COVID-19 to humans, starting the pandemic. It is not an easy task, and international politics is making it that much more difficult. (Anthony Regalado / Technical review of MIT)
Development
The wild ride of AstraZeneca
On Monday, AstraZeneca announced that its vaccine was 79 percent effective. The next day, the government issued an incredibly unusual public rebuke to the company, saying that these figures were out of date. AstraZeneca released new figures later this week, finding that it was actually 76% effective. Wow. In the end, it is a very good vaccine with a bad communication problem. The hearings of the FDA committee for this will be interesting. (Nicole Wetsman / The Verge)
Pfizer starts testing its vaccine in young children
Children under 12 are starting to participate in clinical trials for COVID-19 vaccines. Pfizer and Moderna are starting their own trials to test how well vaccines work in younger patients – and whether they are safe. (Apoorva Mandavilli / The New York Times)
Here is a great video from our colleagues at Vox explaining the differences between the vaccine’s effectiveness numbers.
Perspectives
There were two weeks in the summer when all she smelled was the smell of phantom smoke. The smell was so strong that she woke up one morning frightened, convinced that something in her house was on fire. Some time later, she was able to smell her boyfriend’s cologne again – but instead of the familiar smell she always loved, it was a nauseating chemical odor. There is also the hand soap in action, which used to smell generously fruity for her, but now it smells exactly, and frighteningly, like Burger King’s Whoppers.
– Sarah Zhang writes about the experience of Ruby Martinez recovering her sense of smell after COVID-19 in The Atlantic.
On December 10, my health plan charged me $ 536,000. My plan paid off most, but I still owe about $ 150,000. This does not include my implant account. Medical bills are overdue; it takes months for things to happen. At first, it was stressful for me to look at them, but now it’s a joke. I look at them and think, I don’t know how to pay for it. My prize is $ 750 a month, and my co-workers have been helping to cover that.
– Liza Fisher tells journalist Wudan Yan about the costs of COVID-19 in a report for Intelligencer.
More than numbers
To the more than 505 million people who have been vaccinated – thank you.
For the more than 125,864,307 people worldwide with a positive test, may their path to recovery be smooth.
To the family and friends of the 2,761,409 people who died worldwide – 547,756 in the United States – their loved ones will not be forgotten.
Be safe, everyone.