Covid-19 cases are on the rise again in the United States. But this time the story is more complicated than in the previous waves.
Since the beginning of January, when the US peaked with an average of 260,000 new cases every day, the number of cases has declined more or less consistently. In the months that followed, tens of millions of people were vaccinated against Covid-19. By the end of June, the country was recording an average of just 11,000 new cases a day, according to the New York Times tracker.
But on July 13, the US was seeing an average of about 25,000 new cases a day, twice as many as a few weeks ago.
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So far, hospital admissions have not increased that much: they have increased only slightly, from a seven-day average of 16,500 two weeks ago to about 19,500. The death toll is also still quite low: a daily average of 330 a day, compared to January when the US lost more than 3,000 people a day. Both measures are still on the rise, if not as quickly as the falls.
Confirmed cases are a leading indicator. Someone tests positive for the disease, but it can be two weeks before they're sick enough to go to the hospital and longer before they die if they don't recover. (One caveat: testing rates have dropped significantly in the past few months, so we may not recognize every new case. But that only makes the surge in confirmed cases more worrying.)
This is still true – as cases accelerate, deaths eventually rise too – and current trends reflect this fundamental reality.
But this time around half of the country is fully vaccinated against Covid-19. Some of these people could still get the virus, but their illness is much more mild after receiving the vaccine. The Biden administration announced last week that almost all of the Covid-19 hospital admissions and deaths reported now have come from unvaccinated people.
"The decoupling between cases and deaths has really happened," Andrew Pavia, who specializes in infectious diseases at the University of Utah, told reporters at a briefing from the Infectious Diseases Society of America this week. "We're seeing an increase in deaths, but not nearly as much as before."
However, as long as the virus is circulating, there are risks, especially for half of the population who are not vaccinated. The Delta variant appears more transmissible and virulent than its predecessors, and while vaccines seem to be doing well, it still accounts for an increasing proportion of cases in the US.
Hospital stays and deaths are also becoming more common among younger people, another difference from previous increases.
All in all, the situation is much more chaotic than it was last year when hospital stays and deaths would increase like clockwork after a surge in cases. Here are three factors to keep in mind for the future.
1) Unvaccinated people are still very susceptible to Covid-19
Those who are not vaccinated have no protection against the coronavirus – and the increasingly common delta variant appears more dangerous than previous virus iterations. Right now, it accounts for almost half of the new cases in the US and is expected to become the dominant strain.
As Vox's Umair Irfan explained, the Delta variant appears to be 60 percent more transmissible than the alpha variant first identified in the UK – which was probably already 60 percent more transmissible than the version of the virus first identified in humans.
Early evidence suggests that the Delta variant is also more virulent: A study conducted in Scotland found that people who contracted the Delta variant were twice as likely to end up in hospital, although the death rate did not appear to be significantly worse seemed.
"As more unvaccinated people get the Delta variant, hospital admissions may actually increase," said David Celentano, an epidemiologist at the John Hopkins School of Public Health.
Different states also have different degrees of susceptibility, with vaccination rates by state ranging from 78 percent of Vermonters who are fully vaccinated to just 42 percent of Alabamians. This has led to an increase in cases: the states with the most new cases (including parts of the South, Midwest, and West) per capita are all in the lower half of the states for vaccination rates.
A health care worker distributes water to people waiting in the observation area after receiving a dose of a COVID-19 vaccine on March 30, 2021 in Apple Valley, California.
Mario Tama / Getty Images
In addition, there is the change in which age groups are affected by Covid-19: According to a survey by the Kaiser Family Foundation, 85 percent of all people over 65 state to be vaccinated. But that percentage drops in the younger cohorts to 66 percent of people between 50 and 64, 59 percent of people between 30 and 49 and 55 percent of people between 18 and 29 years of age.
2) Vaccines protect the people hardest hit by Covid-19
These trends contain both good and bad news. The bad news is obvious: Because younger people and people in certain states are less likely to be vaccinated against Covid-19, they are still more likely to get the disease. Especially with the increasing dominance of the delta variant, a higher proportion of them end up in the hospital. Some will die.
According to CDC data, the proportion of people between the ages of 18 and 49 who were hospitalized with Covid-19 has increased from 20 percent of the January total to more than 40 percent now. Americans 65 and older accounted for more than half of Covid-19 hospital admissions in January; they are now less than 30 percent.
To be clear, overall hospital admissions are still far from their peak, so the raw number of seriously ill young people is not as large as the number of older people hospitalized during the worst winter wave. But, in relative terms, younger people now make up a larger proportion of hospital admissions.
The good news is the downside of this trend: the people most vulnerable to dying from Covid-19 have much tougher protection than they did last year. We have known since the pandemic began that age, like anything else, is the best indicator of a person's risk of succumbing to Covid-19.
This is why nursing home residents and workers were prioritized when mass vaccination began in early 2021. According to an AARP analysis of federal data, almost 80 percent of people in nursing homes were fully vaccinated against Covid-19 at the end of June.
In the course of the pandemic, they accounted for a disproportionately large proportion of Covid-19 deaths – 133,482 of 608,000 total deaths in the United States. But death rates in this population slowed significantly when vaccinations came up. In early January, US nursing homes reported more than 5,000 resident deaths each week, according to federal data.
In the last week of June, nursing homes reported only 147 resident deaths. This is a remarkable advance in protecting the most vulnerable.
3) Vaccinated people can become infected with Covid-19, but the cases are almost always mild
The Covid-19 vaccines are very good, but they're not perfect. Some people who have been fully vaccinated will contract the coronavirus, and they may also be responsible for some of the rising case numbers.
When Pfizer / BioNTech and Moderna vaccines were first approved, the amazing rates of effectiveness caught all the attention as they prevented any disease in 95 percent of people during clinical trials. But even then, 5 percent of those vaccinated became ill.
This proportion will grow as the delta variant becomes more dominant; As Irfan reported, early evidence suggests the Pfizer / BioNTech vaccine is still 80 percent effective at preventing disease. However, this means that more people who are vaccinated may become infected with the virus and experience symptoms if the variant spreads further.
That's still a high success rate. The World Health Organization said this week that most vaccinated people who become infected with the Delta variant have no symptoms. They might also be less likely to spread the virus as they shed less of it, CDC deputy director Jay Butler told reporters at the Infectious Diseases Society of America briefing.
And the vaccines still offer impressive protection against serious illness, which is reflected in the tiny numbers of vaccinated people who are hospitalized or who die of Covid-19.
"Breakthrough infections tend to be milder," said Butler. "Even if an infection occurs, the (vaccination) reduces the risk of hospitalizations and death."
Rising cases are not ideal. Millions of Americans are still vulnerable to Covid-19, and a more dangerous variant of the virus is emerging. The number of deaths that occur every day is still the same as a jetliner crashes every 24 hours.
But this is a different kind of wave than the one before it, with nearly 160 million Americans now fully vaccinated. The solution is the same as in the last six months, as Celentano informed me by email: "The best way to avoid acquiring SARS-CoV-2 is to get vaccinated now!"
Otherwise there are risks as long as the virus is circulating.
"The more viruses circulate, the more mutations appear and the more likely another new variant will appear," said Jen Kates, director of global health at the Kaiser Family Foundation.
A new variant, more lethal, more transmissible or more resistant to vaccines, "would of course have more serious public health effects".