ReportWire

Tag: grade school

  • How Much Less to Worry About Long COVID Now

    How Much Less to Worry About Long COVID Now

    [ad_1]

    Compared with the worst days of the pandemic—when vaccines and antivirals were nonexistent or scarce, when more than 10,000 people around the world were dying each day, when long COVID largely went unacknowledged even as countless people fell chronically ill—the prognosis for the average infection with this coronavirus has clearly improved.

    In the past four years, the likelihood of severe COVID has massively dropped. Even now, as the United States barrels through what may be its second-largest wave of SARS-CoV-2 infections, rates of death remain near their all-time low. And although tens of thousands of Americans are still being hospitalized with COVID each week, emergency rooms and intensive-care units are no longer routinely being forced into crisis mode. Long COVID, too, appears to be a less common outcome of new infections than it once was.

    Read: The future of long COVID

    But where the drop in severe-COVID incidence is clear and prominent, the drop in long-COVID cases is neither as certain nor as significant. Plenty of new cases of the chronic condition are still appearing with each passing wave—even as millions of people who developed it in years past continue to suffer its long-term effects.

    In a way, the shrinking of severe disease has made long COVID’s dangers more stark: Nowadays, “long COVID to me still feels like the biggest risk for most people,” Matt Durstenfeld, a cardiologist at UC San Francisco, told me—in part because it does not spare the young and healthy as readily as severe disease does. Acute disease, by definition, eventually comes to a close; as a chronic condition, long COVID means debilitation that, for many people, may never fully end. And that lingering burden, more than any other, may come to define what living with this virus long term will cost.

    Most of the experts I spoke with for this story do think that the average SARS-CoV-2 infection is less likely to unfurl into long COVID than it once was. Several studies and data sets support this idea; physicians running clinics told me that, anecdotally, they’re seeing that pattern play out among their patient rosters too. The number of referrals coming into Alexandra Yonts’s long-COVID clinic at Children’s National, in Washington, D.C., for instance, has been steadily dropping in the past year, and the waitlist to be seen has shortened. The situation is similar, other experts told me, among adult patients at Yale and UCSF. Lisa Sanders, an internal-medicine physician who runs a clinic at Yale, told me that more recent cases of long COVID appear to be less debilitating than ones that manifested in 2020. “People who got the earliest versions definitely got whacked the worst,” she said.

    That’s reflective of how our relationship to COVID has changed overall. In the same way that immunity can guard a body against COVID’s most severe, acute forms, it may also protect against certain kinds of long COVID. (Most experts consider long COVID to be an umbrella term for many related but separate syndromes.) Once wised up to a virus, our defenses become strong and fast-acting, more able to keep infection from spreading and lingering, as it might in some long-COVID cases. Courses of illness also tend to end more quickly, with less viral buildup, giving the immune system less time or reason to launch a campaign of friendly fire on other tissues, another potential trigger of chronic disease.

    In line with that logic, a glut of studies has shown that vaccination—especially recent and repeated vaccination—can reduce a person’s chances of developing long COVID. “There is near universal agreement on that,” Ziyad Al-Aly, an epidemiologist and a clinician at Washington University in St. Louis, told me. Some experts think that antiviral use may be making a dent as well, by decreasing the proportion of COVID cases that progress to severe disease, a risk factor for certain types of long COVID. Others have pointed to the possibility that more recent variants of the virus—some of them maybe less likely to penetrate deeply into the lungs or affect certain especially susceptible organs—may be less apt to trigger chronic illness too.

    But consensus on any of these points is lacking—especially on just how much, if at all, these interventions help. Experts are divided even on the effect of vaccines, which have the most evidence to back their protective punch: Some studies find that they trim risk by 15 percent, others up to about 70 percent. Paxlovid, too, has become a point of contention: While some analyses have shown that taking the antiviral early in infection helps prevent long COVID, others have found no effect at all. Any implication that we’ve tamed long COVID exaggerates how positive the overall picture is. Hannah Davis, one of the leaders of the Patient-Led Research Collaborative, who developed long COVID during the pandemic’s first months, told me that she’s seen how the most optimistic studies get the most attention from the media and the public. With a topic as unwieldy and challenging to understand as this, Davis said, “we still see overreactions to good news, and underreactions to bad news.”

    That findings are all over the place on long COVID isn’t a shock. The condition still lacks a universal definition or a standard method of diagnosis; when recruiting patients into their studies, research groups can rely on distinct sets of criteria, inevitably yielding disparate and seemingly contradictory sets of results. With vaccines, for instance, the more wide-ranging the set of potential long-COVID symptoms a study looks at, the less effective shots may appear—simply because “vaccines don’t work on everything,” Al-Aly told me.

    Studying long COVID has also gotten tougher. The less attention there is on COVID, “the less likely people are to associate long-term symptoms with it,” Priya Duggal, an infectious-disease epidemiologist at Johns Hopkins University, told me. Fewer people are testing for the virus. And some physicians still “don’t believe in long COVID—that’s what I hear a lot,” Sanders told me. The fact that fewer new long-COVID cases are appearing before researchers and clinicians could be in part driven by fewer diagnoses being made. Al-Aly worries that the situation could deteriorate further: Although long-COVID research is still chugging along, “momentum has stalled.” Others share his concern. Continued public disinterest, Duggal told me, could dissuade journals from publishing high-profile papers on the subject—or deter politicians from setting aside funds for future research.

    Even if new cases of long COVID are less likely nowadays, the incidence rates haven’t dropped to zero. And rates of recovery are slow, low, and still murky. At this point, “people are entering this category at a greater rate than people are exiting this category,” Michael Peluso, a long-COVID researcher at UCSF, told me. The CDC’s Household Pulse Survey, for instance, shows that the proportion of American adults reporting that they’re currently dealing with long COVID has held steady—about 5 to 6 percent—for more than a year (though the numbers have dropped since 2021). Long COVID remains one of the most debilitating chronic conditions in today’s world—and full recovery remains uncommon, especially, it seems, for those who have been dealing with the disease for the longest.

    Exact numbers on recovery are tricky to come by, for the same reasons that it’s difficult to pin down how effective preventives are. Some studies report rates far more optimistic than others. David Putrino, a physical therapist who runs a long-COVID clinic at Mount Sinai Health System, where he and his colleagues have seen more than 3,000 long-haulers since the pandemic’s start, told me his best estimates err on the side of the prognosis being poor. About 20 percent of Putrino’s patients fully recover within the first few months, he told me. Beyond that, though, he routinely encounters people who experience only partial symptom relief—as well as a cohort that, “no matter what we think to try,” Putrino told me, “we can’t even seem to stop them from deteriorating.” Reports of higher recovery rates, Putrino and other experts said, might be conflating improvement with a return to baseline, or mistakenly assuming that people who stop responding to follow-ups are better, rather than just done participating.

    Read: Long COVID is being erased—again

    Davis also worries that recovery rates could drop. Some researchers and clinicians have noticed that today’s new long-COVID patients are more likely than earlier patients to come in with certain neurological symptoms—among them, brain fog and dizziness—that have been linked to slower recovery trajectories, Lekshmi Santhosh, a pulmonary specialist at UCSF, told me.

    In any case, recovery rates are still modest enough that long-COVID clinics across the country—even ones that have noted a dip in demand—remain very full. Currently, Putrino’s clinic has a waitlist of three to six months. The same is true for clinical trials investigating potential treatments. One, run by Peluso, that is investigating monoclonal-antibody therapy has a waitlist that is “hundreds of people deep,” Peluso told me: “We do not have the problem of not being able to find people who want to participate.”

    Any decrease in long-COVID incidence may not last, either. Viral evolution could always produce a new variant or subvariant with higher risks of chronic issues. The protective effects of vaccination may also be quite temporary, and the fewer people who keep up to date with their shots, the more porous immunity’s safety net may become. In this way, kids—though seemingly less likely to develop long COVID overall—may remain worryingly vulnerable, Yonts told me, because they’re born entirely susceptible, and immunization rates in the youngest age groups remain extremely low. And yet, little kids who get long COVID may need to live with it the longest. Some of Yonts’s patients have barely started grade school and have already been sick for three-plus years—half of their lives so far, or more.

    Long COVID can also manifest after repeat infections of SARS-CoV-2—and although several experts told me they think that each subsequent exposure poses less incremental risk, any additional exposure is worrisome. People all over the world are being exposed, over and over again, as the pathogen spreads with blistering speed, more or less year-round, in populations that have mostly dropped mitigations and are mostly behind on annual shots (where they’re available). Additional infections can worsen the symptoms of people living with long COVID, or yank them out of remission. Long COVID’s inequities may also widen as marginalized populations, less likely to receive vaccines or antivirals and more likely to be exposed to the virus, continue to develop the condition at higher rates.

    There’s no question that COVID-19 has changed. The disease is more familiar; the threat of severe disease, although certainly not vanished, is quantitatively less now. But dismissing the dangers of the virus would be a mistake. Even if rates of new long-COVID cases continue to drop for some time, Yonts pointed out, they will likely stabilize somewhere. These risks will continue to haunt us and incur costs that will keep adding up. Long COVID may not kill as directly as severe, acute COVID has. But people’s lives still depend on avoiding it, Putrino told me—“at least, their life as they know it right now.”

    [ad_2]

    Katherine J. Wu

    Source link

  • The COVID Question That Will Take Decades to Answer

    The COVID Question That Will Take Decades to Answer

    [ad_1]

    To be a newborn in the year 2023—and, almost certainly, every year that follows—means emerging into a world where the coronavirus is ubiquitous. Babies might not meet the virus in the first week or month of life, but soon enough, SARS-CoV-2 will find them. “For anyone born into this world, it’s not going to take a lot of time for them to become infected,” maybe a year, maybe two, says Katia Koelle, a virologist and infectious-disease modeler at Emory University. Beyond a shadow of a doubt, this virus will be one of the very first serious pathogens that today’s infants—and all future infants—meet.

    Three years into the coronavirus pandemic, these babies are on the leading edge of a generational turnover that will define the rest of our relationship with SARS-CoV-2. They and their slightly older peers are slated to be the first humans who may still be alive when COVID-19 truly hits a new turning point: when almost everyone on Earth has acquired a degree of immunity to the virus as a very young child.

    Read: Is COVID a common cold yet?

    That future crossroads might not sound all that different from where the world is currently. With vaccines now common in most countries and the virus so transmissible, a significant majority of people have some degree of immunity. And in recent months, the world has begun to witness the consequences of that shift. The flux of COVID cases and hospitalizations in most countries seems to be stabilizing into a seasonal-ish sine wave; disease has gotten, on average, less severe, and long COVID seems to be somewhat less likely among those who have recently gotten shots. Even the virus’s evolution seems to be plodding, making minor tweaks to its genetic code, rather than major changes that require another Greek-letter name.

    But today’s status quo may be more of a layover than a final destination in our journey toward COVID’s final form. Against SARS-CoV-2, most little kids have fared reasonably well. And as more babies have been born into a SARS-CoV-2-ridden world, the average age of first exposure to this coronavirus has been steadily dropping—a trend that could continue to massage COVID-19 into a milder disease. Eventually, the expectation is that the illness will reach a stable nadir, at which point it may truly be “another common cold,” says Rustom Antia, an infectious-disease modeler at Emory.

    The full outcome of this living experiment, though, won’t be clear for decades—well after the billions of people who encountered the coronavirus for the first time in adulthood are long gone. The experiences that today’s youngest children have with the virus are only just beginning to shape what it will mean to have COVID throughout a lifetime, when we all coexist with it from birth to death as a matter of course.

    At the beginning of SARS-CoV-2’s global tear, the coronavirus was eager to infect all of us, and we had no immunity to rebuff its attempts. But vulnerability wasn’t just about immune defenses: Age, too, has turned out to be key to resilience. Much of the horror of the disease could be traced to having not only a large population that lacked protection against the virus—but a large adult population that lacked protection against the virus. Had the entire world been made up of grade-schoolers when the pandemic arrived, “I don’t think it would have been nearly as severe,” says Juliet Pulliam, an infectious-disease modeler at Stellenbosch University, in South Africa.

    Across several viral diseases—polio, chicken pox, mumps, SARS, measles, and more—getting sick as an adult is notably more dangerous than as a kid, a trend that’s typically exacerbated when people don’t have any vaccinations or infections to those pathogens in their rearview. The manageable infections that strike toddlers and grade-schoolers may turn serious when they first manifest at older ages, landing people in the hospital with pneumonia, brain swelling, even blindness, and eventually killing some. When scientists plot mortality data by age, many curves bend into “a pretty striking J shape,” says Dylan Morris, an infectious-disease modeler at UCLA.

    The reason for that age differential isn’t always clear. Some of kids’ resilience probably comes from having a young, spry body, far less likely to be burdened with chronic medical conditions that raise severe disease risk. But the quick-wittedness of the young immune system is also likely playing a role. Several studies have found that children are much better at marshaling hordes of interferon—an immune molecule that armors cells against viruses—and may harbor larger, more efficient cavalries of infected-cell-annihilating T cells. That performance peaks sometime around grade school or middle school, says Janet Chou, a pediatrician at Boston Children’s Hospital. After that, our molecular defenses begin a rapid tumble, growing progressively creakier, clumsier, sluggish, and likelier to launch misguided attacks against the tissues that house them. By the time we’re deep into adulthood, our immune systems are no longer sprightly, or terribly well calibrated. When we get sick, our bodies end up rife with inflammation. And our immune cells, weary and depleted, are far less unable to fight off the pathogens they once so easily trounced.

    Whatever the explanations, children are far less likely to experience serious symptoms, or to end up in the hospital or the ICU after being infected with SARS-CoV-2. Long COVID, too, seems to be less prevalent in younger cohorts, says Alexandra Yonts, a pediatrician at Children’s National Hospital. And although some children still develop MIS-C, a rare and dangerous inflammatory condition that can appear weeks after they catch the virus, the condition “seems to have dissipated” as the pandemic has worn on, says Betsy Herold, the chief of pediatric infectious disease at the Children’s Hospital at Montefiore, in the Bronx.

    Should those patterns hold, and as the age of first exposure continues to fall, COVID is likely to become less intense. The relative mildness of childhood encounters with the virus could mean that almost everyone’s first infection—which tends, on average, to be more severe than the ones that immediately follow—could rank low in intensity, setting a sort of ceiling for subsequent bouts. That might make concentrating first encounters “in the younger age group actually a good thing,” says Ruian Ke, an infectious-disease modeler at Los Alamos National Laboratory.

    COVID will likely remain capable of killing, hospitalizing, and chronically debilitating a subset of adults and kids alike. But the hope, experts told me, is that the proportion of individuals who face the worst outcomes will continue to drop. That may be what happened in the aftermath of the 1918 flu pandemic, Antia, of Emory, told me: That strain of the virus stuck around, but never caused the same devastation again. Some researchers suspect that something similar may have even played out with another human coronavirus, OC43: After sparking a devastating pandemic in the 19th century, it’s possible that the virus no longer managed to wreak much more havoc than a common cold in a population that had almost universally encountered it early in life.

    Such a fate for COVID, though, isn’t a guarantee. The virus’s propensity to linger in the body’s nooks and crannies, sometimes causing symptoms that last many months or years, could make it an outlier among its coronaviral kin, says Melody Zeng, an immunologist at Cornell University. And even if the disease is likely to get better than what it is now, that is not a very high bar to clear.

    Some small subset of the population will always be naive to the virus—and it’s not exactly a comfort that in the future, that cohort will almost exclusively be composed of our kids. Pediatric immune systems are robust, UCLA’s Morris told me. But “robust is not the same as infallible.” Since the start of the pandemic, more than 2,000 Americans under the age of 18 have died from COVID—a small fraction of total deaths, but enough to make the disease a leading cause of death for children in the U.S. MIS-C and long COVID may not be common, but their consequences are no less devastating for the children who experience them. Some risks are especially concentrated among our youngest kids, under the age 5, whose immune defenses are still revving up, making them more vulnerable than their slightly older peers. There’s especially little to safeguard newborns just under six months, who aren’t yet eligible for most vaccines—including COVID shots—and who are rapidly losing the antibody-based protection passed down from their mothers while they were in the womb.

    A younger average age of first infection will also probably increase the total number of exposures people have to SARS-CoV-2 in a typical lifetime—each instance carrying some risk of severe or chronic disease. Ke worries the cumulative toll that this repetition could exact: Studies have shown that each subsequent tussle with the virus has the potential to further erode the functioning or structural integrity of organs throughout the body, raising the chances of chronic damage. There’s no telling how many encounters might push an individual past a healthy tipping point.

    Racking up exposures also won’t always bode well for the later chapters of these children’s lives. Decades from now, nearly everyone will have banked plenty of encounters with SARS-CoV-2 by the time they reach advanced age, Chou, from Boston Children’s Hospital, told me. But the virus will also continue to change its appearance, and occasionally escape the immunity that some people built up as kids. Even absent those evasions, as their immune systems wither, many older people may not be able to leverage past experiences with the disease to much benefit. The American experience with influenza is telling. Despite a lifetime of infections and available vaccines, tens of thousands of people typically die annually of the disease in the United States alone, says Ofer Levy, the director of the Precision Vaccines Program at Boston Children’s Hospital. So even with the expected COVID softening, “I don’t think we’re going to reach a point where it’s, Oh well, tra-la-la,” Levy told me. And the protection that immunity offers can have caveats: Decades of research with influenza suggest that immune systems can get a bit hung up on the first versions of a virus that they see, biasing them against mounting strong attacks against other strains; SARS-CoV-2 now seems to be following that pattern. Depending on the coronavirus variants that kids encounter first, their responses and vulnerability to future bouts of illness may vary, says Scott Hensley, an immunologist at the University of Pennsylvania.

    Read: Are our immune systems stuck in 2020?

    Early vaccinations—that ideally target multiple versions of SARS-CoV-2—could make a big difference in reducing just about every bad outcome the virus threatens. Severe disease, long COVID, and transmission to other children and vulnerable adults all would likely be “reduced, prevented, and avoided,” Chou told me. But that’s only if very young kids are taking those shots, which, right now, isn’t at all the case. Nor are they necessarily getting protection passed down during gestation or early life from their mothers, because many adults are not up to date on COVID shots.

    Some of these issues could, in theory, end up moot. A hundred or so years from now, COVID could simply be another common cold, indistinguishable in practice from any other. But Morris points out that this reality, too, wouldn’t fully spare us. “When we bother to look at the burden of the other human coronaviruses, the ones who have been with us for ages? In the elderly, it’s real,” he told me. One study found that a nursing-home outbreak of OC43—the purported former pandemic coronavirus—carried an 8 percent fatality rate; another, caused by NL63, killed three out of the 20 people who caught it in a long-term-care facility in 2017. These and other “mild” respiratory viruses also continue to pose a threat to people of any age who are immunocompromised.

    SARS-CoV-2 doesn’t need to follow in those footsteps. It’s the only human coronavirus against which we have vaccines—which makes the true best-case scenario one in which it ends up even milder than a common cold, because we proactively protect against it. Disease would not need to be as inevitable; the vaccine, rather than the virus, could be the first bit of intel on the disease that kids receive. Tomorrow’s children probably won’t live in a COVID-free world. But they could at least be spared many of the burdens we’re carrying now.

    [ad_2]

    Katherine J. Wu

    Source link

  • Is COVID a Common Cold Yet?

    Is COVID a Common Cold Yet?

    [ad_1]

    At the start of the coronavirus pandemic, one of the worst things about SARS-CoV-2 was that it was so new: The world lacked immunity, treatments, and vaccines. Tests were hard to come by too, making diagnosis a pain—except when it wasn’t. Sometimes, the symptoms of COVID got so odd, so off-book, that telling SARS-CoV-2 from other viruses became “kind of a slam dunk,” says Summer Chavez, an emergency physician at the University of Houston. Patients would turn up with the standard-issue signs of respiratory illness—fever, coughing, and the like—but also less expected ones, such as rashes, diarrhea, shortness of breath, and loss of taste or smell. A strange new virus was colliding with people’s bodies in such unusual ways that it couldn’t help but stand out.

    Now, nearly three years into the crisis, the virus is more familiar, and its symptoms are too. Put three sick people in the same room this winter—one with COVID, another with a common cold, and the third with the flu—and “it’s way harder to tell the difference,” Chavez told me. Today’s most common COVID symptoms are mundane: sore throat, runny nose, congestion, sneezing, coughing, headache. And several of the wonkier ones that once hogged headlines have become rare. More people are weathering their infections with their taste and smell intact; many can no longer remember when they last considered the scourge of “COVID toes.” Even fever, a former COVID classic, no longer cracks the top-20 list from the ZOE Health Study, a long-standing symptom-tracking project based in the United Kingdom, according to Tim Spector, an epidemiologist at King’s College London who heads the project. Longer, weirder, more serious illness still manifests, but for most people, SARS-CoV-2’s symptoms are getting “pretty close to other viruses’, and I think that’s reassuring,” Spector told me. “We are moving toward a cold-like illness.”

    That trajectory has been forecast by many experts since the pandemic’s early days. Growing immunity against the coronavirus, repeatedly reinforced by vaccines and infections, could eventually tame COVID into a sickness as trifling as the common cold or, at worst, one on par with the seasonal flu. The severity of COVID will continue to be tempered by widespread immunity, or so this thinking goes, like a curve bending toward an asymptote of mildness. A glance at the landscape of American immunity suggests that such a plateau could be near: Hundreds of millions of people in the U.S. have been vaccinated multiple times, some even quite recently with a bivalent shot; many have now logged second, third, and fourth infections with the virus. Maybe, just maybe, we’re nearing the level of cumulative exposure at which COVID gets permanently more chill. Then again? Maybe not—and maybe never.

    Read: What does it mean to care about COVID anymore?

    The recent trajectory of COVID, at least, has been peppered with positive signs. On average, symptoms have migrated higher up the airway, sparing several vulnerable organs below; disease has gotten shorter and milder, and rates of long COVID seem to be falling a bit. Many of these changes roughly coincided with the arrival of Omicron in the fall of 2021, and part of the shift is likely attributable to the virus itself: On the whole, Omicron and its offshoots seem to prefer infecting cells in the nose and throat over those in the lungs. But experts told me the accumulation of immune defenses that preceded and then accompanied that variant’s spread are almost certainly doing more of the work. Vaccination and prior infection can both lay down protections that help corral the virus near the nose and mouth, preventing it from spreading to tissues elsewhere. “Disease is really going to differ based on the compartment that’s primarily infected,” says Stacey Schultz-Cherry, a virologist at St. Jude Children’s Research Hospital. As SARS-CoV-2 has found a tighter anatomical niche, our bodies have become better at cornering it.

    With the virus largely getting relegated to smaller portions of the body, the pathogen is also purged from the airway faster and may be less likely to be passed to someone else. On the individual level, a sickness that might have once unfurled into pneumonia now gets subdued into barely perceptible sniffles and presents less risk to others; on the population scale, rates of infection, hospitalization, and death go down.

    This is how things usually go with respiratory viruses. Repeat tussles with RSV tend to get progressively milder; post-vaccination flu is usually less severe. The few people who catch measles after getting their shots are less likely to transmit the virus, and they tend to experience such a trivial course of sickness that their disease is referred to by a different name, “modified” measles, says Diane Griffin, a virologist and an immunologist at Johns Hopkins University.

    It’s good news that the median case of COVID diminished in severity and duration around the turn of 2022, but it’s a bit more sobering to consider that there hasn’t been a comparably major softening of symptoms in the months since. The full range of disease outcomes—from silent infection all the way to long-term disability, serious disease, and death—remains in play as well, for now and the foreseeable future, Schultz-Cherry told me. Vaccination history and immunocompromising conditions can influence where someone falls on that spectrum. So too can age as well as other factors such as sex, genetics, underlying medical conditions, and even the dose of incoming virus, says Patricia García, a global-health expert at the University of Washington.

    New antibody-dodging viral variants could still show up to cause more severe disease even among the young and healthy, as occasionally happens with the flu. The BA.2 subvariant of Omicron, which is more immune-evasive than its predecessor BA.1, seemed to accumulate more quickly in the airway, and it sparked more numerous and somewhat gnarlier symptoms. Data on more recent Omicron subvariants are still being gathered, but Shruti Mehta, an epidemiologist at Johns Hopkins, says she’s seen some hints that certain gastrointestinal symptoms, such as vomiting, might be making a small comeback.

    Read: Will we get Omicron’d again?

    All of this leaves the road ahead rather muddy. If COVID will be tamed one day into a common cold, that future definitely hasn’t been realized yet, says Yonatan Grad, an epidemiologist at Harvard’s School of Public Health. SARS-CoV-2 still seems to spread more efficiently and more quickly than a cold, and it’s more likely to trigger severe disease or long-term illness. Still, previous pandemics could contain clues about what happens next. Each of the past century’s flu pandemics led to a surge in mortality that wobbled back to baseline after about two to seven years, Aubree Gordon, an epidemiologist at the University of Michigan, told me. But SARS-CoV-2 isn’t a flu virus; it won’t necessarily play by the same epidemiological rules or hew to a comparable timeline. Even with flu, there’s no magic number of shots or past infections that’s known to mollify disease—“and I think we know even less about how you build up immunity to coronaviruses,” Gordon said.

    The timing of when and how those defenses manifest could matter too. Almost everyone has been infected by the flu or at least gotten a flu shot by the time they reach grade school; SARS-CoV-2 and COVID vaccines, meanwhile, arrived so recently that most of the world’s population met them in adulthood, when the immune system might be less malleable. These later-in-life encounters could make it tougher for the global population to reach its severity asymptote. If that’s the case, we’ll be in COVID limbo for another generation or two, until most living humans are those who grew up with this coronavirus in their midst.

    COVID may yet stabilize at something worse than a nuisance. “I had really thought previously it would be closer to common-cold coronaviruses,” Gordon told me. But severity hasn’t declined quite as dramatically as she’d initially hoped. In Nicaragua, where Gordon has been running studies for years, vaccinated cohorts of people have endured second and third infections with SARS-CoV-2 that have been, to her disappointment, “still more severe than influenza,” she told me. Even if that eventually flips, should the coronavirus continue to transmit this aggressively year-round, it could still end up taking more lives than the flu does—as is the case now.

    Wherever, whenever a severity plateau is reached, Gordon told me that our arrival to it can be confirmed only in hindsight, “once we look back and say, ‘Oh, yeah, it’s been about the same for the last five years.’” But the data necessary to make that call are getting harder to collect as public interest in the virus craters and research efforts to monitor COVID’s shifting symptoms hit roadblocks. The ZOE Health Study lost its government funding earlier this year, and its COVID-symptom app, which engaged some 2.4 million regular users at its peak, now has just 400,000—some of whom may have signed up to take advantage of newer features for tracking diet, sleep, exercise, and mood. “I think people just said, ‘I need to move on,’” Spector told me.

    Mehta, the Johns Hopkins epidemiologist, has encountered similar hurdles in her COVID research. At the height of the Omicron wave, when Mehta and her colleagues were trying to find people for their community studies, their rosters would immediately fill up past capacity. “Now we’re out there for weeks” and still not hitting the mark, she told me. Even weekly enrollment for their long-COVID study has declined. Sign-ups do increase when cases rise—but they drop off especially quickly as waves ebb. Perhaps, in the view of some potential study volunteers, COVID has, ironically, become like a common cold, and is thus no longer worth their time.

    For now, researchers don’t know whether we’re nearing the COVID-severity plateau, and they’re worried it will get only more difficult to tell. Maybe it’s for the best if the mildness asymptote is a ways off. In the U.S. and elsewhere, subvariants are still swirling, bivalent-shot uptake is still stalling, and hospitalizations are once more creeping upward as SARS-CoV-2 plays human musical chairs with RSV and flu. Abroad, inequities in vaccine access and quality—and a zero-COVID policy in China that stuck around too long—have left gaping immunity gaps. To settle into symptom stasis with this many daily deaths, this many off-season waves, this much long COVID, and this pace of viral evolution would be grim. “I don’t think we’re quite there yet,” Gordon told me. “I hope we’re not there yet.”

    [ad_2]

    Katherine J. Wu

    Source link