Cows stand at a feedlot on June 14, 2023 in Quemado, Texas.
Brandon Bell | Getty Images
U.S. health officials are monitoring bird flu in humans and preparing to combat it, even as they emphasize that the risk to the general public remains low.
A strain of bird flu called H5N1 has been confirmed in dairy cows in nine U.S. states and in two people, while there has been an outbreak in poultry and other animals worldwide. The most recent case was A dairy farm worker in Michigan made the announcement on Wednesday. A child in Australia was also recently infected with bird flu, the country announced on Tuesday.
H5N1 has been spreading among more animal species worldwide since 2020, but its detection in U.S. livestock earlier this year was a turn that health authorities did not expect. In rare cases, bird flu viruses spread to humans and can cause mild to severe symptoms that may require hospitalization.
There is currently no evidence that H5N1 is transmitted from person to person. The Centers for Disease Control and Prevention has also said the risk of infection is higher among farmworkers than the general population.
However, the U.S. government, along with state and local health authorities, is monitoring new and emerging infections in humans and animals. Federal authorities in the United States and elsewhere have also been tracking the H5N1 virus for years to monitor its development.
The U.S. government has long stockpiled vaccines and medicines for use in a possible bird flu pandemic. Preparation of nearly 5 million vaccine doses expected to work well against H5N1 began last week and further measures were taken to respond, the Department of Health and Human Services confirmed to CNBC.
Some infectious disease experts told CNBC that the U.S. government appears broadly prepared if bird flu spread further and more easily to humans, especially given how well the country is prepared for the Covid pandemic was. The experts said most of the necessary tools are already in place, but the government needs to ensure it uses them effectively when needed.
“There are already a lot of things that are helping us understand that we can respond more quickly,” said Dr. Andrew Pekosz, a professor at the Johns Hopkins Bloomberg School of Public Health. “But as always, it depends on the efficiency of our reactions, doesn’t it? We know what we can do. We just need to be able to do it effectively.”
The recent human infection in a Michigan dairy worker is no surprise, experts and the government say. The CDC said Wednesday that similar cases in humans could be identified because high levels of the virus had been found in the raw milk of infected cows.
Millions of vaccine doses
The US government currently has two vaccine candidates that it believes are a good match for H5N1. These candidates are weakened versions of a virus that trigger a protective immune response against it in the body and can be used to make vaccines.
According to the CDC, both candidates are already available to manufacturers. The government last week began producing 4.8 million doses of these human vaccines in case they are needed, HHS confirmed.
Pekosz called those doses a “first line of defense in case there is human-to-human transmission.” He said that number is enough to contain an early-stage outbreak, including vaccinating farmworkers and some health care workers could belong.
But he said far more would be needed for the more than 300 million people in the U.S. if the virus spread widely among people.
“Five million doesn’t really get us very far. It’s just a quick start,” Pekosz said.
U.S. health officials said on May 1 that the government could ship more than 100 million doses of human bird flu vaccines within three to four months if needed, NBC News reported.
Specifically, people will need two doses of a vaccine, meaning 100 million doses are only enough for 50 million people. That suggests the U.S. would need about 600 million doses if it wanted to vaccinate the entire population.
The government faces a difficult decision about how many shots to prepare, especially since they take several months to produce.
“It’s either too little or too much. For example, if you prepare too much food, a lot of food is wasted,” said Dr. Peter Chin-Hong, an infectious disease physician at UCSF Health. “That’s really the big problem with a vaccine when there’s a potential threat. It’s the high cost and high risk.”
Chin-Hong said misinformation and vaccine hesitancy post-Covid make this decision all the more difficult. But he believes you can “never really invest too much” in preparing for potential pandemics, especially at a time when climate change, population growth and other factors increase the likelihood of their occurrence.
The Food and Drug Administration would have to approve bird flu vaccines before they are introduced. But Pekosz said it will likely be a “quick process” because the FDA is used to approving seasonal flu vaccines that are made using the same manufacturing process as bird flu shots.
Possible mRNA recordings
U.S. health officials are also in discussions with messenger RNA vaccine makers about possible bird flu shots for humans. Few details have been released about these negotiations, but HHS said a final announcement is expected soon.
Unlike traditional flu shots, mRNA teaches cells to produce a harmless piece of a virus that triggers an immune response against certain diseases. Both are the same technology Pfizer And Modern have used in their Covid vaccines.
Chin-Hong said mRNA vaccines could be updated more quickly to address currently circulating strains of bird flu. However, he said these vaccines come with their own challenges, such as the need to be stored at extremely cold temperatures.
In a statement to CNBC, Moderna confirmed that it is involved in negotiations with the government over its experimental pandemic flu vaccine mRNA-1018. It targets the exact virus strain responsible for the outbreak in dairy cows.
The biotech company began early- to mid-stage testing of this shot last summer.
Pfizer declined to confirm negotiations with the government. The company said it continues to monitor the spread of H5N1 and is evaluating its mRNA-based pandemic influenza vaccine candidates in an early-stage study.
Virus monitoring and treatments
CDC and its partners, including state and local health departments, use multiple surveillance systems to monitor seasonal influenza and other illnesses. They also have special methods for detecting and monitoring new flu viruses.
Seasonal flu spreads primarily among humans, with predictable peaks throughout the year, while avian flu spreads primarily among wild birds and other animals.
The CDC said it is looking for spread of H5N1 to or among people in areas where the virus has been identified in animals or humans. According to an update on the agency’s website last week, the agency has so far found “no evidence of unusual influenza activity in humans,” including H5N1.
CDC also conducts ongoing analyzes of seasonal and emerging influenza viruses to identify genetic changes that could cause them to cause more serious infections in humans, spread more easily to and between people, or become less susceptible to vaccines and medications.
Although there is robust testing at the federal, state and local levels, it is far more difficult for an average person to test themselves for bird flu and receive a diagnosis, as is the case with Covid, Chin-Hong said. That is “the big hurdle, especially in the population groups that are now affected,” he said.
Chin-Hong refers to farmworkers, a large portion of whom are immigrants, who may have difficulty navigating the U.S. health care system due to language barriers and access to health care.
If humans become infected with the virus, there are some FDA-approved antiviral medications for seasonal flu that can be used for bird flu. This includes Tamiflu, an oral prescription medication that should be taken within 48 hours of symptoms appearing.
A Texas dairy farm worker who was diagnosed with bird flu in March was treated with an antiviral drug and recovered, according to a CDC report.
But Pekosz said the antiviral drugs in the country’s stockpile are unlikely to be enough for the vast majority of the population, so manufacturers may be asked to increase their supply.
According to Francesca Torriani, an infectious disease specialist at UC San Diego Health, the average person can protect themselves from bird flu by avoiding any living or dead animals that might be infected, such as farm animals or chickens.
Persons who must come into contact with these animals should wear an appropriate mask and eye protection and wash their hands afterwards.
Torriani added that consuming pasteurized milk and cheese is probably safer than raw dairy products because the pasteurization process kills harmful bacteria.
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2024-05-24 23:09:44
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