As the world recovers from the devastation of Covid-19, it faces the possibility of a pandemic from a much deadlier pathogen.
Bird flu—known more formally as avian influenza—has long hovered on the horizons of scientists’ fears. This pathogen, particularly the H5N1 strain, does not usually infect humans, but when it has, 56 percent of those known to have contracted it have died. Its inability to spread easily from person to person has prevented it from causing a pandemic.
But things are changing. The virus, which has long caused outbreaks among poultry, is infecting more and more migratory birds, allowing it to spread more widely, including to various mammals, raising the risk of a new variant spreading to people and between them.
A mutant H5N1 strain was recently reported to be infecting mink on a fur farm in Spain and likely spreading among them, something unprecedented among mammals. Worse, the mink’s upper respiratory tract is well-suited to act as a conduit to humans, said Thomas Peacock, a virologist who has studied avian influenza.
The world needs to act now, before H5N1 becomes a devastating pandemic.
The best defense against a deadly new pathogen is to aggressively suppress early outbreaks, which first requires rapid detection. The United States, the World Health Organization and global health officials all have influenza surveillance networks, but many bird flu experts say they don’t think the networks are working well enough given the level of threat.
Thijs Kuiken, an avian influenza expert at the Erasmus University Medical Center in Rotterdam, the Netherlands, said pig farms, another species susceptible to influenza, should also be monitored for avian influenza. People who interact with birds and wildlife, as well as susceptible pets like ferrets, are also at higher risk. However, it is not enough to detect: suppression would require a great effort and global coordination.
Unfortunately, mink farms have to be shut down, even if it means culling them. They are usually killed for their fur anyway at around 6 months of age. It’s hard to imagine a better way to incubate and spread a deadly virus than to let it evolve among tens of thousands of animals with upper respiratory tracts similar to ours crammed together. When the coronavirus infected Danish mink farms in 2020 and the mink spawned new variants that later infected humans, efforts to save the industry were futile because the outbreaks were uncontrollable.
The US Government has a small stock of vaccines against the H5N1 virus. The plan is to mass produce them if an outbreak occurs.
However, producing hundreds of millions of doses of a new vaccine in the US alone could take six months or more.
The troubling thing: All but one of the approved vaccines are produced by incubating each dose in an egg. The US Government keeps hundreds of thousands of chickens in secret farms with bodyguards. But the bodyguards are supposedly there to defend against terrorist attacks, not a virus. The only company with a non-egg-based H5N1 vaccine approved in the US expects to be able to produce 150 million doses within six months of a pandemic declaration. But there are 7 billion people in the world.
The mRNA-based platforms used to make two of the Covid vaccines are also not dependent on eggs. Scott Hensley, an influenza expert at the University of Pennsylvania, said those vaccines can be mass-produced faster, in as little as three months. There are no approved mRNA vaccines for influenza, but efforts to make one should be accelerated.
A big challenge for stockpiling flu vaccines is that they can lose potency over time and need to be updated as new variants emerge. Many flu experts said older vaccines might still provide some protection against serious outcomes or death.
Voluntary vaccination could also be allowed, especially for high-risk groups such as poultry workers and health care workers. Voluntary vaccination could also produce larger-scale data on the safety and specific doses of vaccines. Vaccinating poultry workers has the great added benefit of helping to suppress outbreaks in the first place. Several experts lamented the lack of more widespread vaccination for chickens and turkeys. If all poultry had been vaccinated earlier, the H5N1 virus might never have spread as widely among wild birds.
Mass vaccination of poultry and pigs must begin quickly. Even vaccinating more people, especially poultry and pig farm workers, against the common flu can help.
We have influenza antivirals, which work regardless of strain, but need to be administered early, which requires widespread early testing, easy access, and sufficient and equitable stocks around the world. Scientists are working toward a universal flu vaccine, potentially covering all variants as well as future pandemics — a wild dream, perhaps, but well worth the investment.
The pace of events has been unsettling. Until 2020, when the new H5N1 strain began to spread widely among wild birds, most large outbreaks occurred among poultry. But now, with wild birds acting as conduits, it is not only the largest outbreak among poultry, killing at least 150 million animals so far, but it is also steadily expanding its reach, including species of mammals like dolphins and bears.
In 2006, when scientists discovered that H5N1 had not spread easily between humans because it sits deep in their lungs, Kuiken of the Erasmus University Medical Center warned that if the virus evolved to bind to receptors in the upper respiratory tract—from where it could more easily spread through the air—the risk of a human-to-human pandemic would increase substantially. The mink outbreak in Spain is a sign that we may be heading down exactly that path. It’s hard to imagine more dire warning signs of a horrendous pandemic.
We might be lucky: We’ve had outbreaks of bird flu without human spread. But it seems silly to count on that. A pandemic strain could have a much lower fatality rate than the 56 percent of human cases known so far, but it could still be much more deadly than the coronavirus, which is estimated to have killed between 1 and 2 percent. of infected people before vaccines or treatments were available.
Now, we not only have the warning, but also many of the tools we need to defend ourselves against a pandemic. We must not wait.
By: INTELLIGENCE / ZEYNEP TUFEKCI
BBC-NEWS-SRC: http://www.nytsyn.com/subscribed/stories/6564924, IMPORTING DATE: 2023-02-09 23:00:07
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