US evaluates vaccinating chickens after avian flu outbreak – 07/03/2023 – Market

President Joe Biden’s administration, mindful of an outbreak of avian flu that has killed tens of millions of chickens and is driving up the price of eggs — not to mention raising fears of a human pandemic — is considering a vaccination campaign. of the birds, according to White House officials.

The avian flu outbreak, which began early last year, is the largest in the country’s history, affecting more than 58 million poultry raised in 47 states, as well as wild birds. The disease has already spread to mammals such as martens, foxes, raccoons and bears, raising fears that the virus that causes it, known as H5N1, could mutate and begin to spread more easily among humans.

Experts at the Centers for Disease Control and Prevention (CDC), which focuses on human health, say the risk of a pandemic is low. As a precaution, the agency sent drug manufacturers samples of the flu virus that could form the basis of vaccines for people. The CDC is also exploring whether commercial test makers would be willing to develop tests for H5N1, similar to those used for the coronavirus.

Bird flu infections in humans are rare, and human-to-human transmission of bird flu is extremely rare. Worldwide, there have been nine cases of H5N1 reported in people since the beginning of last year, according to the World Health Organization. In Cambodia, an 11-year-old girl recently died of H5N1 and her father was also infected with the virus, but scientists found no evidence of human-to-human transmission in these cases and the virus was a different version than the one currently circulating among birds in the US. .

Cases usually involve people exposed to domestic birds. In the United States, the CDC, in partnership with state and local public health departments, is monitoring people exposed to H5N1. Until last week, 6,315 people had been monitored; 163 reported symptoms; and one tested positive, according to Dr. Tim Uyeki, medical director of the CDC’s flu division.

At the same time, officials at the Federal Department of Agriculture, which is responsible for the health of farm animals, say they have begun testing potential vaccines for poultry and have begun discussions with industry leaders about a large-scale avian flu vaccination program to birds, which will be a pioneer in the United States.

Farmed birds are already vaccinated against infectious poultry diseases such as fowlpox. But an avian flu vaccination program would be a complex undertaking, and poultry trade associations are divided on the idea, in part because it could introduce trade restrictions that could destroy the $6 billion export industry. Dr. Carol Cardona, an avian health expert at the University of Minnesota, said fear of trade bans is a huge barrier to mass vaccination of birds.

“This is undeclared war – commerce,” said Dr Cardona.

White House officials, speaking on condition of anonymity because of internal deliberations, say vaccinating birds is not the only step they are considering. On a more immediate level, they are dedicated to encouraging farms to avoid transmission of the virus through biosecurity measures, such as improved disinfection procedures for their employees.

Avian flu experts, however, say they believe the government should move ahead with a vaccination campaign, in part to reduce the risk of a human pandemic. In interviews, several urged the government to act quickly.

“In my opinion, under the current circumstances, we should vaccinate the US poultry population against H5N1 without a doubt,” said Robert G. Webster, an avian flu specialist at the St. Paul’s. Jude Children’s Research Hospital in Memphis. Such a campaign could “prevent inevitable transmission to humans,” he said.

For President Biden, there are also political considerations at work. Egg prices, which skyrocketed in 2022, were 70% higher in January than a year earlier. Those high prices have given Republicans yet another opportunity to attack Biden on inflation as he prepares to run for re-election in 2024.

Experts say egg prices could continue to rise through the spring, driven in part by Easter demand but also by a shortage of supplies linked to the avian flu outbreak. And the outbreak could get worse in the coming months, as wild birds begin their spring migrations, bringing the virus with them.

White House officials said they are closely watching price fluctuations. If a vaccination drive could provide economic relief to families, Biden would certainly be interested in such an endeavor, an official said.

Experts have long feared that a human-adapted version of avian flu could trigger a global pandemic. That’s why the United States and the world need to do more to prepare, said James Krellenstein, a consultant at international consulting firm Global Health Strategies.

Krellenstein and Garrett Wilkinson, a health policy expert at the nonprofit Partners in Health, examined the world’s preparedness for an H5N1 pandemic and identified several “key gaps,” according to a report they shared with The New York Times. With a two-dose regimen, the United States could need at least 650 million doses of the H5N1 vaccine for use in humans, and the report said it was unclear how the country could reach that number with its current production capacity.

“While it is extremely important that there be serious efforts to control the outbreak in domestic and wild birds, the reality of the situation is serious enough that we are taking further steps to prepare for a possible human outbreak of this virus,” Krellenstein said in an interview, adding : “We should see this as a live fire drill.”

Before Covid-19, many experts predicted that the next pandemic would be caused by the flu. In 2020, the Federal Department of Health and Human Services published a ten-year strategy to upgrade influenza vaccine production; one of the White House officials said the Biden administration was reviewing the document in light of the current avian outbreak.

One step in preparing for a pandemic would be a poultry vaccination campaign, many experts agree.

“The simple fact that the virus is less widespread would reduce exposure to humans,” said Anice C. Lowen, an influenza virologist at Emory University, adding that a vaccination effort “would also reduce the potential for viral evolution” that could allow the virus to spread effectively between people.

Currently, federal regulators have not authorized vaccinating poultry against highly infectious strains of bird flu such as H5N1, said Mike Stepien, a spokesman for the Department of Agriculture. While there are several licensed vaccines, it’s unclear whether any of them are effective against the current strain, he said.

Department scientists have been working to develop candidate vaccines, said Erica Spackman, a research microbiologist at the agency’s Agricultural Research Service, who is one of the scientists leading the poultry vaccine trials. Dr. Spackman and her colleagues plan to test several potential vaccines — including those already licensed and new candidate vaccines — in chickens, turkeys and domestic ducks, she said.

If existing vaccines prove effective, they could be rolled out faster than new ones. Typically, the approval process for pet vaccines can take up to three years, although Stepien said the time frame could be shortened in an emergency.

Dr. Spackman estimated that she and her colleagues probably wouldn’t have their first set of results ready to share until May. “And there’s always the question on the production side of how quickly the company could actually produce and deliver the vaccine,” she added.

In addition to science, there are economic considerations. The United States is one of the world’s largest exporters of poultry products, and its trading partners want assurances that they are not importing meat from infected poultry. Vaccination can make it more difficult to prove that birds have not been infected.

Broilers — the industry term for chickens raised for meat — make up the bulk of poultry exports, said Amy Hagerman, an agricultural economist at Oklahoma State University. It is therefore not surprising that the National Poultry Council, which represents the poultry industry, is opposed to vaccination.

“While initially appealing as a simple solution to a pervasive and difficult problem, vaccination is neither a solution nor a simple one,” said Tom Super, senior vice president of communications for the council.

He said the chicken industry exports 18% of its meat and that losing the ability to export chicken would cost “billions and billions of dollars”.

But the turkey sector, which has been hit hard by the virus and exports just 9% of its meat, is open to vaccination. “We recognized that unilateral vaccination would have a severe impact on exports,” said Joel Brandenberger, president of the Turkish National Federation. “At the same time, we urge and continue to urge the federal government to act as quickly as possible to try to develop new agreements” with trading partners.

Avian influenza is usually transmitted by waterfowl and shorebirds, which transmit the virus to domestic birds through their faeces or respiratory secretions. During previous outbreaks, authorities eradicated the virus by enforcing biosecurity measures, quarantining affected farms and culling infected herds. But with the virus now unusually widespread in wild birds, those measures have failed to contain the spread.

A handful of countries where avian flu is endemic, including China, Egypt and Vietnam, already routinely vaccinate birds against it. Vaccines are usually injected into individual birds and require more than one dose, said Dr Leslie Sims, an international veterinary consultant in the prevention and control of zoonotic diseases who lives in Australia.

While the cost varies, it can be as low as a few cents per dose, he added.

Still, even vaccine advocates recognize that a mass vaccination campaign would not be a quick job. The United States produces over 9 billion chickens a year for meat alone. A large egg-laying facility, which can hold 5 million birds, could take two years to vaccinate enough birds to achieve high levels of population immunity, said Dr Cardona.

Some critics have previously raised concerns that vaccination could reduce the severity of the disease in birds without interrupting transmission, which could allow the virus to spread through flocks undetected while encouraging the emergence of new immune variants. evasive. But Richard J. Webby, an avian flu expert at St. Jude Children’s Research Hospital, said “there’s not a lot of evidence for that, at least in a quality vaccination program.”

Whichever path the United States takes, Dr. Webby said, the virus is likely to become endemic in wild birds in America.

“This thing is here to stay,” he said.

Translated by Luiz Roberto M. Gonçalves