The most recent influenza pandemic, the 2009 H1N1 “swine flu,” was a public health crisis in the absolute sense of the word. Scientists Best QuoteAn estimated 200,000 to 300,000 people worldwide have died and countless more have fallen ill. Children, Youthand Pregnant people was particularly hard hit.
That being said, it could have been a lot worse. Known influenza pandemicsThe 2009 pandemic had the fewest deaths. The H1N1 pandemic, which began in 1918, was caused by an influenza virus that spread Estimated 500 million people At least 50 million people have died worldwide. Even the latest seasonal flu has killed more people than swine flu. Seema Lakdawala, a virologist at Emory University, says that with swine flu, “we’ve been lucky”: the H5N1 avian flu that’s raging among animals hasn’t really taken off among humans yet. But if that changes, the world might not have the same relief the next time a flu pandemic hits.
Swine flu took scientists by surprise. At the time, many researchers were convinced that H5N1, which had originated somewhere in Asia, would be the next influenza pandemic. Their focus was on birds, and few looked at pigs. But the virus, a descendant of the devastating flu strain that caused the 1918 pandemic, had invaded pigs and rapidly acquired the ability to hack into human airway cells. Good at moving in the airLakdawala said swine flu had the perfect characteristics to cause global havoc. By the time experts realized the true threat of swine flu, “there was already a huge amount of cases being reported,” said Nahid Bhadelia, founding director of the Center for Emerging Infectious Diseases at Boston University. Researchers were scrambling to catch up. But testing was patchy, and Case reports were inconsistentIt’s been hard for scientists to grasp the spread of the virus, as months have passed since new vaccines began to be rolled out and vaccination rates have slowed. SlightEven well-resourced countries like the United States had few defenses to thwart the virus’s initial onslaught.
But the worst never happened, and experts still don’t understand why. To be sure, modern medicine is better equipped to test for and treat influenza than the 1918 pandemic or those of the 1950s and 1960s. Vaccinations weren’t perfect, but Any Sam Scarpino, an infectious disease modeller and chair of the AI and Life Sciences department at Northeastern University, said vaccination increased overall protection. More subtle effects may have also played a role. Troy Sutton, a virologist at Pennsylvania State University, said other H1N1 viruses have circulated globally since the late 1970s, which may have provided some immunity to much of the population. senior citizenIn particular, further exposure to H1N1 viruses in the first half of the 20th century may have equipped the flu virus with additional protection. (Variants of this virus survived and continued to infiltrate the population for decades after the 1918 pandemic.) This extra layer of protection may explain why younger people were more severely affected in 2009, Lakdawala told me.
Some of the same factors may also influence H5N1 outbreaks. But 2009 is an imperfect template, especially because so much remains unknown about this new avian flu. The chances that H5N1 could actually spread from person to person remain remote. To do so, the virus would almost certainly need to undergo major evolutionary changes to its genome, possibly mutating into something almost unrecognizable. All of this clouds predictions about how future outbreaks will unfold.
Still, experts are closely monitoring several factors that could increase the risk of H5N1 influenza, including the fact that no version of the virus has ever achieved sustained establishment in humans., “This means there’s very little immunity in the community,” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
Exposure to other flu strains may offer only limited protection. Lakdawala and Sutton are working with ferrets, which carry and develop influenza similar to that in humans. Preliminary results suggest that animals previously exposed to seasonal flu strains will be less ill the next time they get this particular H5N1. But ferrets who’ve never had the flu (which applies to very young ones) are more sick than they were with the 2009 H1N1, which Lakdawala said is “scary.”
It is too early to say how these results will affect people. data It is rare. This H5N1 virus It was first discovered in the 1990sScientists have documented hundreds of human cases. Nearly half Of those, 1 million died. But experts strongly caution against overinterpreting these statistics. Because no one knows how many people the virus actually infected, it’s impossible to estimate the actual fatality rate. Also, viruses have morphed over decades, and the ones that killed people don’t seem to have the ability to spread to people. As Sutton points out, past experiments suggest that mutations that make H5 viruses more infectious may also make them more infectious. Non-fatalBut that’s not a guarantee. For example, the 1918 flu was “highly contagious between humans.” and It caused very serious illness,” Sutton said.
Scientists believe that the recent outbreak of H5N1 infections among U.S. dairy workers may be due to Recorded as mildBhadelia noted that many of the farm workers are relatively young and healthy, and their infection was likely via raw milk that contained the virus. The virus could have a more dramatic effect on other communities, and the nature of the disease could change if the virus enters the body in a different way. And short-term “mild” symptoms aren’t always reassuring, Scarpino said. Like COVID, the disease can still have chronic effects on a person’s health.
In some ways, the world is better prepared for the H5N1 virus than it was in 2009. Scientists have been following the bird flu for decades. In the past few years alone, they’ve watched the virus jump through dozens of animal species and tracked its genetic modifications. Experts in the U.S. are already testing wastewater for the pathogen, and federal regulators are taking steps to stop it from spreading to poultry and livestock. H5 vaccines are in stockpiles, with more on the way; the recent addition of mRNA technology could make the pipeline faster than ever.
But as the worst of the COVID-19 pandemic approaches, Osterholm and others worry that it could be harder to stop any spread if it doesn’t. “We could have a lot of people refusing to get vaccinated,” he said. (Especially if the vaccine doesn’t work.) 2 servings Badglia echoed that concern, adding that social media is already awash with misinformation. Scarpino also noted that after the fierce debate over school closures in the COVID era, lawmakers may refuse to consider the option again, even though children are the best vectors for the flu virus. Stopping a pandemic requires trust, cooperation and public buy-in. On that score alone, Osterholm said, “I definitely think we’re underprepared.”
The world has a track record of not taking influenza seriously, even when it sometimes causes pandemics. For months after the first swine flu outbreak, it was ridiculed as inconsequential and public health officials Criticized Blame it on the wolf boy. But despite what was supposedly a “mild” flu epidemic, hospital emergency departments were packed. Pneumonia patientsspreading the virus Score of Health care workers; The children are still I got sick a lotSo many young people died that, in terms of years of life lost, the 2009 toll exceeded that of the entire influenza pandemic that began in 1957, Osterholm told me. 1968Comparisons to seasonal flu aren’t necessarily comforting either: Most years, these epidemics result in deaths. Tens of thousands In the US alone.
H5N1 could also permanently change the world’s annual influenza burden. An avian flu pandemic could be the perfect opportunity for this virus to join other seasonal influenza strains, becoming an endemic threat that may be with us forever. “We’ve seen this phenomenon every flu pandemic we’ve had,” Sutton told me. More circulating influenza viruses could mean more flu cases each year. Or it could mean more opportunities for these viruses to mix genetic material and produce new versions to which people have no immunity.
However likely these possibilities may be, they can all be prevented by stopping the spread of H5N1 now. Scientists are predicting bird flu differently than they did pre-pandemic swine flu, and by exploiting the most important differences between the two strains of influenza, we may be able to avoid experiencing another pandemic.
