Not long before the end of the school year, my husband and I received an e-mail from our fifth-grader’s principal that may now be all-too-familiar to many parents. The subject line included the words, “MULTIPLE COVID CASES.”

Several students in my daughter’s class had tested positive for COVID-19. Her school acted fast. It reinstated a mask mandate for 10 days and required students not up-to-date on their COVID-19 vaccinations to quarantine.

These precautions may have helped — my daughter didn’t end up bringing the virus home. But for kids who do, COVID-19 can hopscotch through households, knocking down relatives one by one. And it’s not clear how long one infection protects you from a second round with the virus.
Recent high-profile cases have put reinfections in the spotlight. Health and Human Services Secretary Xavier Becerra has had two bouts of COVID-19 in less than a month. So has The Late Show host Stephen Colbert. Back at his desk in May, he joked, “You know what they say. ‘Give me COVID once, shame on you. Give me COVID twice, please stop giving me COVID.’”

Just a few months ago, scientists thought reinfections were relatively rare, occurring most often in unvaccinated people (SN: 2/24/22). But there are signs the number may be ticking up.

An ABC News investigation that contacted health departments in every state reported June 8 that more people seem to be getting the virus again. And omicron, the variant that sparked last winter’s surge, is still spawning sneaky subvariants. Some can evade antibodies produced after infection with the original omicron strain, scientists report June 17 in Nature. That means a prior COVID-19 infection might not be as helpful against future infections as it once was (SN:8/19/21). What’s more, reinfection could even add to a person’s risk of hospitalization or other adverse outcomes, a preliminary study suggests.

Scientists are still working to pin down the rate of reinfection. Like most questions involving COVID-19 case numbers, the answer is more than a little murky. “You really need to have a cohort of people who are well followed and tested every time they have symptoms,” says Caroline Quach-Thanh, an infectious diseases specialist at CHU Sainte-Justine, a pediatric hospital at the University of Montreal.

A recent look at hundreds of thousands of COVID-19 cases among people in the province of Quebec found that roughly 4 percent were reinfections, scientists report in a preliminary study posted May 3 at medRxiv.org (SN:5/27/22). Quach-Thanh has seen an even smaller rate in her own study of health care workers first infected between March and September of 2020. Those data are still unpublished, but she points out that most of the people in her study were vaccinated. “A natural infection with three doses of vaccines protects better than just a natural infection,” she says.

As many families, mine included, gear up for summer camps and vacations, I wanted to learn more about our current COVID-19 risks. I chatted with Quach-Thanh and Anna Durbin, an infectious diseases physician at Johns Hopkins Bloomberg School of Public Health who has studied COVID-19 vaccines. Our conversations have been edited for length and clarity.

What’s the latest on reinfections? Is the picture changing?
Durbin: We have to remember that the virus strain that’s circulating now is very different from the earlier strains. Whether you’ve been infected with COVID-19 or vaccinated, your body makes an immune response to fight future infections. It recognizes [the strain] your body originally saw. But as the virus changes, as it did with omicron, it becomes sort of a fuzzier picture for the immune system. It’s not recognizing the virus as well, and that’s why we’re seeing reinfections.

I’ll also say that reinfections — particularly with respiratory viruses — are very common.

How can scientists distinguish a true reinfection from a relapse of an original infection?
Quach-Thanh: There are multiple ways of looking at this. The first is looking at the time elapsed between the first infection and a new positive PCR test. If it has been more than three months, it is unlikely to be just a remnant of a previous infection. We can also look at viral load. A really high viral load usually means it’s a new infection. But the best way to tell is to sequence the virus [to determine its genetic makeup] to see if it is actually a new strain.

What do we know about the health risks of reinfection?
Quach-Thanh: The good thing is that most of the people who got reinfected [in the Quebec study] got a mild disease, and the risk of hospitalization and death was much lower.

When you get reinfected, you might [have symptoms] like a cold, or even sometimes a cough, and a little bit of a fever, but you usually don’t progress to complications as much as you would with your first infection — if you’re vaccinated.

Does reinfection increase your chance of developing long COVID?
Durbin: I think that’s unknown, but it’s being studied.

As we look back at the omicron wave in the U.S. that happened in January and February, now is about the time we would start to see symptoms of long COVID. So far it looks promising. We seem to be seeing a lower incidence of long COVID [after reinfection with omicron] than we did with primary infection, but those data are going to continue to be collected over the next few months.

At this point in the pandemic, how cautious do we need to be?
Quach-Thanh: It depends on your baseline risk of complications. If you’re healthy, if you’re doing most activities outdoors, if you’re vaccinated, life can proceed. But if you’re immune suppressed or elderly, the situation might be different.
If you have symptoms, it would be advisable to not mingle in indoor settings without a mask so that you don’t contaminate other people. There are immunocompromised people who might be at risk of serious infection. We still need to keep them in mind. I think we have to be responsible, and if we’re sick, we should get tested.

Durbin: This is what I tell my friends, family and patients: This virus is here to stay. Any time you’re in a crowded place with poor ventilation and lots of people, there’s a chance there’s going to be transmission. The risk is never going to be zero. It’s a message people don’t want to hear. But as long as there are people to infect, this virus is not going away.

We have to move to acceptance, and we have to be better members of society. If we can, we should stay home when we’re sick. If we can’t stay home, we should wear a mask. We should wash our hands regularly. These are things that work to reduce transmission.

They reduce your risk of getting not just COVID-19, but also a cold or the flu.

A flexible sensor applied to the back of the neck could help researchers detect whiplash-induced concussions in athletes.

The sensor, described June 23 in Scientific Reports, is about the size of a bandage and is sleeker and more accurate than some instruments currently in use, says electrical engineer Nelson Sepúlveda of Michigan State University in East Lansing. “My hope is that it will lead to earlier diagnosis of concussions.”

Bulky accelerometers in helmets are sometimes used to monitor for concussion in football players. But since the devices are not attached directly to athletes’ bodies, the sensors are prone to false readings from sliding helmets.
Sepúlveda and colleagues’ patch adheres to the nape. It is made of two electrodes on an almost paper-thin piece of piezoelectric film, which generates an electric charge when stretched or compressed. When the head and neck move, the patch transmits electrical pulses to a computer. Researchers can analyze those signals to assess sudden movements that can cause concussion.

The team tried out the patch on the neck of a human test dummy, dropping the figure from a height of about 60 centimeters. Researchers also packed the dummy’s head with different sensors to provide a baseline level of neck strain. Data from the patch aligned with data gathered by the internal sensors more than 90 percent of the time, Sepúlveda and colleagues found.

The researchers are now working on incorporating a wireless transmitter into the patch for an even more streamlined design.

There’s a lot more to the story of the Higgs boson than just one man named Higgs.

Despite the appeal of the “lone genius” narrative, it’s rare that a discovery can be attributed solely to the work of one scientist. At first, Elusive, a biography of Peter Higgs written by physicist and author Frank Close, seems to play into that misleading narrative: The book is subtitled “How Peter Higgs solved the mystery of mass.”

But the book quickly — and rightfully — veers from that path as it delves into the theoretical twists and turns that kicked off a decades-long quest for the particle known as the Higgs boson, culminating with its discovery in 2012 (SN: 7/28/12, p. 5). That detection verified the mechanism by which particles gain mass. Higgs, of the University of Edinburgh, played a crucial role in establishing mass’s origins, but he was one of many contributors.

The habitually modest and attention-averse Higgs makes the case against himself as the one whiz behind the discovery, the book notes: According to Higgs, “my actual contribution was only a key insight right at the end of the story.”

The Higgs boson itself doesn’t bestow fundamental particles with mass. Instead, its discovery confirmed the correctness of a theory cooked up by Higgs and others. According to that theory, elementary particles gain mass by interacting with a field, now known as the Higgs field, that pervades all of space.

A paper from Higgs in 1964 was not the first to propose this process. Physicists Robert Brout and François Englert just barely beat him to it. And another team of researchers published the same idea just after Higgs (SN: 11/2/13, p. 4). Crucial groundwork had already been laid by yet other scientists, and still others followed up on Higgs’ work. Higgs, however, was the one to make the pivotal point that the mass mechanism implied the existence of a new, massive particle, which could confirm the theory.
Despite this complicated history, scientists slapped his name on not just the particle, the Higgs boson, but also the process behind it, traditionally called the Higgs mechanism, but more recently and accurately termed the Brout-Englert-Higgs mechanism. (Higgs has reportedly proposed calling it the “ABEGHHK’tH mechanism,” using the first letter of the last names of the parade of physicists who contributed to it, Anderson, Brout, Englert, Guralnik, Hagen, Higgs, Kibble and ’t Hooft.) The postmortem of how Higgs’ name attained outsize importance is one of the most interesting sections of Elusive, revealing much about the scientific sausage-making process and how it sometimes goes awry. Equally fascinating is the account of how the media embraced Higgs as a titan of physics based on his association with the boson, lofting him to a level of fame that, for Higgs, felt unwelcome and unwarranted.

The book admirably tackles the complexities of the Brout-Englert-Higgs mechanism and how particles gain mass, covering details that are usually glossed over in most popular explanations. Close doesn’t shy away from nitty-gritty physics terms like “perturbation theory,” “renormalization” and “gauge invariance.” The thorniest bits are most appropriate for amateur physics aficionados who desire a deeper understanding, and those bits may require a reread before sinking in.

Higgs is famously not a fan of the limelight — he disappeared for several hours on the day he won a Nobel Prize for his work on mass. The physicist sometimes seems to fade into the background of this biography as well, with multiple pages passing with no appearance or contribution from Higgs. Once the scientific community got wind of the possibility of a new particle, the idea took on a life of its own, with experimental physicists leading the charge. Higgs didn’t make many contributions to the subject beyond his initial insight, which he calls “the only really original idea I’ve ever had.”

Thus, the book sometimes feels like a biography of a particle named Higgs, with the person playing a backup role. Higgs is so reserved and so private that you get the sense that Close still hasn’t quite cracked him. While interesting details of Higgs’ life and passions are revealed — for example, his fervent objection to nuclear weapons — deeper insights are missing. In the end, Higgs is, just like the particle named after him, elusive.

You might want to bring your dumbbells on that next spaceflight.

During space missions lasting six months or longer, astronauts can experience bone loss equivalent to two decades of aging. A year of recovery in Earth’s gravity rebuilds about half of that lost bone strength, researchers report June 30 in Scientific Reports.

Bones “are a living organ,” says Leigh Gabel, an exercise scientist at the University of Calgary in Canada. “They’re alive and active, and they’re constantly remodeling.” But without gravity, bones lose strength.
Gabel and her colleagues tracked 17 astronauts, 14 men and three women with the average age of 47, who spent from four to seven months in space. The team used high-resolution peripheral quantitative computed tomography, or HR-pQCT, which can measure 3-D bone microarchitecture on scales of 61 microns, finer than the thickness of human hair, to image the bone structure of the tibia in the lower leg and the radius in the lower arm. The team took these images at four points in time — before spaceflight, when the astronauts returned from space, and then six months and one year later — and used them to calculate bone strength and density.

Astronauts in space for less than six months were able to regain their preflight bone strength after a year back in Earth’s gravity. But those in space longer had permanent bone loss in their shinbones, or tibias, equivalent to a decade of aging. Their lower-arm bones, or radii, showed almost no loss, likely because these aren’t weight-bearing bones, says Gabel.

Increasing weight lifting exercises in space could help alleviate bone loss, says Steven Boyd, also a Calgary exercise scientist. “A whole bunch of struts and beams all held together give your bone its overall strength,” says Boyd. “Those struts or beams are what we lose in spaceflight.” Once these microscopic tissues called trabeculae are gone, you can’t rebuild them, but you can strengthen the remaining ones, he says. The researchers found the remaining bone thickened upon return to Earth’s gravity.
“With longer spaceflight, we can expect bigger bone loss and probably a bigger problem with recovery,” says physiologist Laurence Vico of the University of Saint-Étienne in France, who was not part of the study. That’s especially concerning given that a crewed future mission to, say, Mars would last at least two years (SN: 7/15/20). She adds that space agencies should also consider other bone health measures, such as nutrition, to reduce bone absorption and increase bone formation (SN: 3/8/05). “It’s probably a cocktail of countermeasure that we will have to find,” Vico says.

Gabel, Boyd and their colleagues hope to gain insight on how spending more than seven months in space affects bones. They are part of a planned NASA project to study the effects of a year in space on more than a dozen body systems. “We really hope that people hit a plateau, that they stop losing bone after a while,” says Boyd.