Nearly half the US population is fully vaccinated, but rates still vary widely from state to state – and even more widely county by county.
Around 1,000 US counties currently have vaccination rates below 30%, Rochelle Walensky, director of the Centers for Disease Control and Prevention, said at a White House press briefing on Thursday.
“These communities, primarily in the Southeast and Midwest, are our most vulnerable,” Walensky said. “In some of these areas, we are already seeing increasing rates of disease. As the Delta variant continues to spread across the country, we expect to see increased transmissions in these communities unless we can vaccinate more people now.”
Delta is the most transmissible coronavirus variant to date, and may be deadlier than its predecessors, so disease experts are particularly concerned about its spread among unvaccinated communities.
An analysis from Public Health England found that Delta was associated with a 60% increased risk of household transmission compared with the Alpha variant discovered in the UK, though more recent estimates suggest the difference is closer to 40%. The Alpha variant is already about 50% more transmissible than the original strain, according to the Centers for Disease Control and Prevention.
Researchers in Scotland also found that getting infected with the Delta variant doubled the risk of hospital admission relative to Alpha. (Previous studies have suggested that the Alpha variant may be 30 to 70% deadlier than the original strain.)
Vaccines, of course, significantly lower that risk for both variants. The Associated Press recently reported that around 99% of COVID-19 deaths in May were among unvaccinated people, based on government data.
But the US has struggled recently to convince more Americans to get vaccinated, even with incentives like cash prizes, gift cards, and tickets to sports games. Vaccination rates have fallen 85% in the last three months. As of Wednesday, the US was administering less than 430,000 daily doses, on average, compared to a peak of more than 3 million daily doses in April. The nation will likely fall shy of its goal to vaccinate 70% of adults with at least one dose by July 4 – 67% of adults have gotten at least one shot so far.
Meanwhile, Delta is expected to become the dominant strain in the US in a matter of weeks. It currently represents around 25% of the country’s reported cases, Walensky said. In some regions, she added, Delta already represents nearly half of new cases.
The spread of Delta has corresponded to a roughly 10% increase in weekly average of new coronavirus cases in the US. In the last two weeks, 19 states have seen their average daily cases rise. Missouri – where roughly four dozen counties have vaccination rates below 30% – has seen cases increase 55% during that time. In Arkansas – where more than 20 counties have vaccination rates below 30% – cases have risen 63%.
The pandemic has made the world keenly aware that the biggest threats to public health often come in small packages. Individual virus particles, called virions, are too small to be seen without a high-power microscope, but they’re responsible for hijacking our cells and replicating inside our bodies.
In the case of the coronavirus, scientists estimate that each infected person carries between 1 billion and 10 billion virions during the peak of their infection. That means that at the current moment, quadrillions of virions are likely circulating in humans. (The world is recording around 323,000 new COVID-19 cases each day.)
But if you were add up all those virions around the globe, they’d weigh no more than 22 pounds (10 kilograms). And it’s possible that their total weight is as low as 100 grams – less than a pound. That’s according to a new study from researchers at the Weizmann Institute of Science in Israel and the California Institute of Technology.
The results were striking even to scientists, according to Avi Flamholz, a research associate at Caltech.
“For the whole world to be basically brought to its knees by 10 kilograms, that’s still surprising,” Flamholz told Insider.
He added, “If you would’ve thought about it intuitively, you would have chosen a much bigger number, because our intuition is like, ‘This is a big deal.'”
Flamholz and his fellow researchers estimate that a single infected cell contains about 100,000 virions – around 10 to 100 of which are actually infectious. But it only takes a few infectious virions to make someone severely ill, he said.
“You’re going to get potentially hundreds of individual virions out of that single infection event, and each of them is going to have some low probability of infection,” Flamholz said. “But they will also, if they infect, give rise to hundreds more.”
All the virions in an infected person weigh less than a poppy seed
To estimate the number of virions inside an infected person, the researchers used measurements of the virus’ genetic material – in this case, RNA – from the tissues of rhesus monkeys. Since it’s unethical to perform these studies on people, monkeys give us the closest sense of how the virus replicates in humans. For this research, the monkeys had been injected with the virus two to four days prior to the measurements.
To determine how much viral RNA was present in the monkey samples, scientists ran them through a machine called a thermocycler, which gives off a fluorescent signal when genetic material is present. The less time it takes for the machine to complete a cycle, the more RNA genomes a sample contains. The researchers assumed that the amount of RNA genomes corresponded to the number of virions inside the body.
Overall, the researchers found the highest concentration of RNA copies in the lungs. So they relied on that number to estimate the total weight of the virions in one infected person. That weight, they found, ranges from 1 to 100 micrograms – up to 100 times lighter than a poppy seed.
Still, Flamholz said, “there are good reasons to approach this number with scientific skepticism because you’re testing the RNA, but you’re not testing the number of particles or the number of infectious particles.”
That’s why the researchers’ estimate ranges from 1 billion to 10 billion virions per person. That also accounts for the fact that the virus affects everyone differently, so some people have more virions than others.
“You see this crazy variation among even your friends, let’s say, who might’ve had COVID in terms of their degree of severity,” Flamholz said.
A single infection might produce up to 100 million mutations
Over the course of the study, the researchers stumbled on another finding: By determining the number of virions produced during a single infection, they could also determine how many mutations occur, based on previous estimates of the virus’ mutation rate.
They calculated that a given strain likely develops around three mutations per month. Although most mutations are harmless, scientists still worry that the virus could develop even more dangerous combinations of mutations that help it spread quickly or evade vaccines.
“The rate of emergence of new mutants and the odds of them being more infectious or having longer residence times in the body – that’s work that we should all collectively be concerned with now,” Flamholz said.
The researchers estimate, for instance, that 1 out of every 200,000 infections might have a particular mutation known as E484K – which is present in the most concerning variants so far.
Flamholz said the study findings are primarily another reminder that tiny particles can have a deadly global impact.
“We live in a macroscopic world where things weigh 100 kilograms. Gravity is a force that matters. When we jump, we fall and we sink to the bottom of the pool unless we’re swimming,” he said. “Those things are not true for the microscopic scale.”
By the time coronavirus vaccines were rolled out to the public, tens of thousands of people had already received their shots in clinical trials.
The results of those studies gave us a good sense of how well the vaccines worked: Pfizer’s was found to reduce the risk of getting COVID-19 by 95%, while Moderna’s had an efficacy of 94.5%. Johnson & Johnson’s single-dose shot, meanwhile, was found to cut the risk of infection by 66% globally – and by 72% among US trial participants.
But the three trials were difficult to compare side by side, since they happened at different stages in the pandemic and in different geographic regions.
Now, real-world studies are beginning to offer a clearer picture of how well the vaccines perform outside trials and in the face of emerging variants.
For the most part, it’s great news: Pfizer and Moderna’s vaccines seem to be just as effective in real life as in their trials. Recent studies have also found that both shots prevent asymptomatic infections, a result that wasn’t yet known when the trial data came out.
A March report from the Centers for Disease Control and Prevention found that Pfizer and Moderna’s shots were, as a whole, 80% effective at preventing coronavirus infections – with or without symptoms – after just one dose, and 90% effective after two doses.
Similarly, an Israeli study found that Pfizer’s vaccine was 94% effective against asymptomatic infections. That’s likely a sign that the shots reduce transmission.
J&J’s shot also seems to be matching its trial results in real life.
A recent study, which is still awaiting peer review, found that J&J’s shot was about 76% effective at preventing all coronavirus infections. (Clinical trials suggested it was 74% effective at preventing asymptomatic infections.)
But the study’s sample size was small: around 1,800 patients observed at The Mayo Clinic from February to April. Just three of those individuals tested positive for the coronavirus 15 days or more after getting vaccinated.
Vaccines are holding up well against variants
As coronavirus variants began to circulate widely in December, some scientists worried that Pfizer’s or Moderna’s shots would stop performing as well as they did in the summer and fall. That’s because the companies’ late-stage trials took place from July to November, when new coronavirus variants weren’t as prevalent.
By contrast, J&J’s late-stage trial took place slightly later in the pandemic, from September to January. The trial also included participants who got infected with B.1.351, a variant first identified in South Africa. The variant has been shown to partially evade antibodies generated in response to vaccines or prior natural infections.
But a large study of Pfizer recipients in Israel suggests that new variants haven’t diminished the vaccine’s effectiveness. From January to March, the Israel Ministry of Health collected data from millions of people who were vaccinated with Pfizer’s shot. By that time, B.1.1.7, a more contagious variant first discovered in the UK, was the dominant strain in Israel.
Pfizer’s vaccine was still found to be at least 97% effective against symptomatic COVID-19 cases, hospitalizations, and deaths.
Pfizer’s shot has also performed well against variants in Qatar: New research found that people in Qatar who were fully vaccinated with Pfizer’s shot were 75% less likely to get a COVID-19 case caused by the B.1.351 variant than unvaccinated people were. They were also around 90% less likely to develop COVID-19 caused by the B.1.1.7 variant discovered in the UK.
“The vaccines that we have so far seem to be effective against most of the variants, if not all the variants, they’ve really been tested against,” David Dowdy, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, told Insider.
Pfizer’s side effects may be less common in real life
Coronavirus vaccines have generally produced mild, short-lived side effects both in and out of clinical trials. But emerging evidence suggests that Pfizer’s side effects may be less common in real life.
Around 63% of participants in Pfizer’s clinical trial reported fatigue, while 55% reported headaches and 38% reported muscle pain. But after 28,000 Pfizer recipients recorded their side effects in an app, UK researchers analyzed the data and found that less than 15% of people reported fatigue after either their first or second dose. Similarly, less than 14% of the people self-reported headaches and 5% or less reported muscle pain after either their first or second dose.
In J&J’s case, however, rolling out the vaccine to the public revealed a very rare side effect that wasn’t spotted in clinical trials. As of Wednesday, the CDC had identified 28 cases of thrombocytopenia syndrome – a rare combination of blood clots and low platelet counts – among 8.7 million recipients of J&J’s vaccine.
“When you start vaccinating people, you have a much, much, much larger sample size – in the millions,” Dr. Vivek Cherian, an internal-medicine physician in Baltimore, previously told Insider. “So when you have these exceedingly rare complications, sometimes you don’t see that until you actually start.”
Since the clotting cases are around 3 in 1 million so far, the CDC has said the benefits of J&J’s shot far outweigh the risks. But the vaccine’s label now warns that the shot may pose an increased risk of clotting, particularly among women under 50.
The practice of contact tracing – or identifying, assessing, and managing people who have been exposed to a disease – is an essential tool for controlling outbreaks by interrupting a disease’s transmission chains. And indeed, combined with lockdowns and mask ordinances, some countries have had great success using contact tracing to reduce outbreaks.
So why have attempts to institute it failed in so many other countries, most notably the US? And given that COVID is likely to be with us in some form for quite a while, are there ways to make contact tracing more effective here?
Sarit Markovich, a clinical professor of strategy at the Kellogg School, says that contact tracing, at its core, hinges on trust. This means that trust will need to be at the foundation of any successful efforts moving forward. This includes building trust in the technology, specifically in terms of false positives, trust that information will be kept private, and trust that people will not suffer consequences for self-reporting.
Here, she offers her thoughts on where contact tracing can fail, and how to do it better.
Consider your social makeup
Contact tracing requires individuals to share private information in service to the public good. In considering how to solicit this information, it helps to understand the difference between centralized and decentralized societies, Markovich said.
In countries with centralized governments, like China or Singapore, contact tracing is mandated and compliance is universal. Governments track people’s movement through a national phone app or wearable tokens, which people scan as they move between locations. Noncompliance is heavily fined. In general, these societies prioritize collective welfare over individual freedoms, like privacy.
“If the government makes you do it, you do it,” Markovich summarized. “And now in many of those places, people are back to their offices and normal life.”
But in democratic societies where government is decentralized, individual rights can be in tension with public health, Markovich said. Strategies that are effective in centralized societies are less likely to work in decentralized ones.
In Israel, for example, the government-mandated digital contact tracing and levied hefty fines for noncompliance. Given the country’s population size and relative homogeneity, it seemed as if national contact tracing would work much like it did in Singapore, Markovich said. But people objected to being tracked. They turned off or left their phones at home, and the initiatives have been unsuccessful.
“In decentralized societies, people do not completely trust the technology and do not completely trust authorities knowing where they are,” Markovich said. “They want privacy.”
Lower-tech approaches, where public health workers individually interview exposed individuals about their contacts, are unfortunately no more promising.
In Israel, for example, a volunteer-led startup tried to launch in-person contact tracing as an alternative to the government’s digital model. The initiative stalled when it turned out residents did not want to share personal information with strangers. That same skepticism exists in the US, where 41% of people in a recent Pew survey said that they wouldn’t speak to a public health official who contacted them by phone or text.
“The goal is to make people get used to contact tracing in a context that’s not scary and in a way where its effect on others is not negative but positive,” she said.
Keep it local
For now, Markovich believes that in decentralized societies, national contact tracing initiatives won’t work. A better option: hand the lead over to local governments and organizations.
At this smaller scale, Markovich says contact tracing becomes easier to centralize. Initiatives can be heavily encouraged or even mandated, and enforcement is also easier when it is tied to the social pressures of local communities or the requests of employers.
“Organizations and municipalities have an advantage because there’s more trust involved,” Markovich said. “They can centralize and mandate it, because if you want to be part of an organization – an employee at your company, for example – there are rules you will have to comply with.”
Over time, Markovich believes that the number of organizations and communities that mandate contact tracing will grow, especially as more local models – a church, a factory, or a city whose leaders have established trust – start to show success.
Reward disclosure without punishing exposure
She also advises that local communities and organizations think carefully about how to encourage people to disclose their contacts. This means, first and foremost, minimizing the negative consequences on all parties: those who have tested positive and are disclosing their contacts, as well as the individuals whom they have exposed.
Here, technology has a powerful role to play. Markovich observes that in some communities, COVID-positive people are blamed for spreading the virus. This practice of “COVID-shaming” could make them less likely to self-report their contacts.
“This is where technology helps,” Markovich said. “You want to use technology rather than rely on people to tell you who they’ve been in contact with or that they’re sick. It’s not about self-reporting. The technology tells you.”
But despite the benefits of technology that can automatically notify people of exposure (see sidebar), Markovich also notes that the human element shouldn’t be ignored. Follow up calls from trained professionals will provide an opportunity for people to ask questions about next steps, express concerns, and learn how to self-isolate, if required.
“The human part is important,” Markovich said. “Technology is great in terms of detection speed, but human contact creates trust.”
And whatever the technology used, if people do have to quarantine because they’ve been exposed to COVID, employers should assure their employees that they will be compensated for the time they self-isolate. Markovich cites incidents in which employees who have been exposed to the virus went to work because they lacked paid sick leave or feared losing their job. Since some sectors are at higher risk for infection, like grocery stores, the government should share these costs with organizations.
“We need incentives to encourage people to tell the truth and feel comfortable staying home,” Markovich said. “If you know that you’re going to be compensated even if you’re home, then you’re definitely going to feel more comfortable self-reporting and self-isolating.”
I’m a physician in Boston, and I’ve been obsessed with the coronavirus pandemic since the first stories trickled out of China into my consciousness. Every day I listen to podcasts and medical lectures by a long line of virologists, epidemiologists, and infectious disease doctors. Every week, I write an essay for my friends and family in my area about what we’ve learned about COVID-19 and how to protect ourselves.
My sons – Mackenzie, 24, and Cooper, 21 – live nearby and have been what I call “COVID-conscious” since the start. Both kids work and study from their apartments, have small friend pods, have excellent COVID hygiene, particularly with me and anyone who falls into a high-risk group, and both had stayed mostly bubbled at home the previous two weeks.
Because of this, we agreed to have a science-based “as-safe-as-we-can-make-it” Thanksgiving following all the techniques I had researched.
We kept it small (just the three of us), we kept it short (two hours), and we kept the kitchen-cooking time to a minimum. We ate with the windows and doors open and the fans on, and the boys sat far apart in the dining room while I ate in the adjacent kitchen. We gathered together only once, for a couple of two-second photos, smiling behind our masks and instinctively inhaling.
In fact, we masked except when actively putting food in our mouths, pulling our masks back up into place between servings and when chatting during the meal.
It all went perfectly.
But then, on Saturday morning while I was walking with a friend, Kenzie texted me saying, “Sooooo, I have bad news.” Half a minute later he sent a second text that read, “I feel horrible.”
I knew instantly what it was – he was sick with COVID-19. Which meant he had been contagious on Thanksgiving.
Every parent has their lowest parenting moment. This was mine. I bent over on the walkway and I just could not stand up.
All I could think was, “Why, why, why didn’t we just skip Thanksgiving this year? And now it’s too late to stop whatever tsunami is coming our way.”
The rest of Kenzie’s texts confirmed my fears: He was sick with a fever, body aches, headache. He had lost his sense of smell and taste. He tested positive for COVID later that day.
This is exactly how COVID-19 spreads: A person, like my beloved son, can have it, be contagious, but have no symptoms at all, not a single clue, for several days before getting sick.
This is exactly why we were so meticulously careful about our Thanksgiving. We knew it was possible one of us could be that asymptomatic contagious person. Not likely, not even probable. Kenzie has five friends in his bubble. All had been tested the week before for travel and were negative. All have been tested since and stayed negative, and all were asymptomatic. He had only shopped, carefully, at a couple of large stores.
We had no reason at all to think any of us had COVID-19 that Thanksgiving Day, but we couldn’t be sure. So we followed the science and opened the windows, turned on the fans, sat far from each other, and masked up nearly every moment we didn’t have a fork in our mouths.
But a “small friend pod,” it turns out, is an oxymoron. And “mostly bubbled” isn’t good enough. There are no shortcuts, no bending of the coronavirus rules.
And as it turned out, the precautions we did have in place worked. Cooper and I are COVID-19 negative. And Kenzie had a rough week but is getting better. We’re all getting better.
But was gathering my little family together for some pumpkin pie worth it?
Was it worth it to have Kenzie feel immense guilt about potentially exposing us? Was it worth the discomfort of having to tell his contacts they needed to be tested and then go into 10 days of quarantine?
Was it worth all the 4 a.m. wake-ups, the test-result anxiety, the constant texting each other to check on symptoms while living through that first week of absolute uncertainty about how things would turn out?
Am I ever going to hold another Thanksgiving in the middle of a pandemic? Absolutely not.
And Christmas in 2020?
No possible way. Not a bit. Not a chance.
Dr. Robin Schoenthaler has been a long-time radiation oncologist at Massachusetts General Hospital. She’s also a writer, story-teller, and an obsessed student of epidemics.
This story originally appeared on Schoenthaler’s Facebook page and on The Boston Globe website. It has been republished with permission.