Bird flu is a real pandemic threat. Are we prepared for the worst? | Devi Sridhar

AAs usual, I’m back with cheerful topics to get us through the dark, cold winter months. No, I’m not talking about the studies on how dark chocolate reduces the risk of type 2 diabetes, or why eating cake for breakfast is not as bad as we think. Instead, the most important news in the global health world is about bird flu, the H5N1 virus and also the deadly outbreak in the Democratic Republic of Congo from a mysterious illness. At these times I wonder why I didn’t choose a career in baking.

But if you want to recreate a Mary Berry recipe, eggs are needed—and the United States is faced with one shortage of eggs – like Great Britain did that last year – with the main culprit being bird flu, which has killed or prompted the culling of hundreds of thousands of chickens. Avian flu has recently raised concerns, given several major changes in the severity of the potential threat: becoming endemic in wild bird populations; it then spread to domestic birds, causing a turkey lockdown in the winter of 2022; then reports from around the world of infections in mammals such as sea lions that feed on or live near wild birds. The past year has seen a sea change in confirmation of mammal-to-mammal transmission among dairy cows in the US.

The increasing proximity of the virus to humans has resulted in an increasing number of human infections (bird-to-human or cow-to-human) over the past year, but H5N1 still cannot be transmitted from person to person like Sars . -Cov-2 or seasonal flu is possible, therefore it is considered low risk. However, a recent Science article noted that the cow strain requires only a single mutation to allow the virus to move from avian specificity to human specificity. This is the shift that would push governments to activate their pandemic preparedness and response plans and vault them to the top of the risk registers.

But there are even more puzzles when you look at H5N1. Before this year, the mortality rate was estimated at about 50%, and it is still fatal to many species of birds and cats. But of the 57 confirmed infections in the US last year, they have all been lenient and no one was hospitalized. Scientists don’t fully understand why, although there are hypotheses: Could the strain that circulates in dairy cows (and causes human infections in the US) be less dangerous to human health? Or is it about the route of transmission from cows to humans, or about existing immunity in the population? It is worth comparing this with a teenager in Canada who was infected with H5N1 from wild birds (a different strain than that found in cows), and was admitted to hospital with severe pneumonia, where he is on a ventilator.

Looking ahead, it would not be wise to simply assume that the disease will not mutate further or that it will be a mild strain. If I worked in a government health department, I would be preparing plans for how best to respond to more cases of bird flu in humans, including guidance from GPs and hospitals, testing of vaccines and antivirals, and plans for stockpiling and containment plans.

First, we must continue to detect cases, which requires a testing strategy and adequate diagnostics. Sequencing positive samples can tell us where someone became infected, what strain they have and how contagious the transmission is. Currently, Britain has one detection strategy for high-risk workers and in hospitals. The first part involves random sampling through nasal and throat swabs for those who work closely with birds on poultry farms, for example to identify asymptomatic cases and ensure we don’t have undetected spread. In the second part, NHS hospitals will ensure that those admitted to intensive care with severe respiratory infections or flu-like symptoms are tested for bird flu, if no seasonal flu is found.

We must also prepare medical countermeasures such as vaccines and antiviral drugs such as Tamiflu. We are fortunate to have an approved vaccine, which has previously been used for people working on a mink farm in Finland Britain has stockpiled Doses of 5 million. While it is useful to have a generic H5N1 vaccine ready, it would not be specific to the strain that is circulating. At a bird flu briefing several months ago, a senior director of the Centers for Disease Control and Prevention noted that the U.S. was holding off on stockpiling vaccines so that they could match the circulating strain as closely as possible, if necessary. But given that producing enough vaccines quickly would be a problem H5N1 vaccines are currently made in eggsthat depend on healthy chickens. The US government spends millions of dollars on… contracts with poultry companies for eggs, kept ready for vaccine production. These chickens are kept in secret locations and protected by both physical and biosecurity measures to ensure the egg supply is safe. It is estimated that it takes at least six months from the arrival of an egg to an approved vaccine, making emergency scale-up difficult.

Furthermore, we need a clear strategy for managing the spread. If the circulating strain is indeed mild in humans, would officials tolerate spread while vaccinating in high-risk groups? What if it is more serious in humans and young people, especially children, become seriously ill? What if hospitals become overwhelmed? What is the plan in this case to curtail and delay vaccination? How do we build trust in yet another vaccination campaign? It is better to anticipate these questions and prepare plans that support decision-making in a logistical and balanced way.

For now, that’s not the case, unless you’re a scientist working in this field, a health or agriculture official, a farm worker or around animals, or you consume raw milk or undercooked meat (which is a bad idea anyway). ). a major concern. But if the image changes further, we can no longer avoid the subject. For now you can continue with your Christmas baking and those precious eggs.