Dr Kessler Ran Operation Warp Speed. He is Concerned About Bird Flu.
Nov. 26, 2024
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A tattered poster of farm animals, including a cow and chickens.
Credit...Steffanie A. Padilla
By David A. Kessler
Dr. Kessler was commissioner of the Food and Drug Administration during the George H.W. Bush and Clinton administrations and was the Biden administration’s chief science officer during Covid-19.
As Donald Trump gets ready to return to the White House on Jan. 20, he must be prepared to tackle one issue immediately: the possibility that the spreading avian flu might mutate to enable human-to-human transmission.
I was the Biden administration’s chief science officer during Covid-19. I was a co-leader of Operation Warp Speed, which began in Mr. Trump’s first term to accelerate the development of Covid-19 vaccines. I worked on the purchase and rollout of hundreds of millions of doses and on developing antiviral treatments. One of my jobs was to assess the trajectory of the virus.
Now I am back at my job teaching at the medical school at the University of California, San Francisco. I have been monitoring the spread of bird flu, also known as H5N1, and discussing the situation with colleagues around the country. My concern is growing.
So far, there have been no reports of person-to-person spread of H5N1, though there have been at least 55 confirmed cases of bird flu in humans in the United States, almost entirely among poultry and dairy workers. Those infections are presumed to be primarily the result of contact with animals. In addition, a child in Alameda County in California with minor respiratory symptoms tested positive for H5N1 recently; it is unclear how the child became infected. There are probably other cases out there that are not being diagnosed.
All of those cases have been mild. But a teenager in British Columbia who was infected with the virus is now critically ill. In this instance, too, it is unclear how the person became infected. But the virus showed signs that it had mutated in a way that could make it easier to transmit to another person.
If this is the case, the virus might then get enough of a foothold to begin human-to-human transmission. Further mutations could evolve that would enhance attachment to human cells. Until the British Columbia case, the recent bird flu infections in humans in North America had been limited to the eyes and nasal passages. But H5N1 can become deadly when the virus attaches to the lining of the lungs in the lower respiratory tract.
This virus killed before. In 1997 an outbreak of H5N1 in poultry in Hong Kong resulted in 18 animal-to-human infections and six deaths, the first known fatal human infections. In 2003, H5N1 appeared in wild birds in Asia. Outbreaks followed in poultry and resulted in two deaths in people. As outbreaks continued to occur, the mortality rate surpassed 50 percent.
Here is where matters stand: The most recent risk assessment from the Johns Hopkins Center for Outbreak Response Innovation, issued on Nov. 19, listed the risk of infection to farm workers as high and the risk of infection to people in contact with affected farm workers and animals as moderate. The Johns Hopkins report said that “while the immediate risk to the general public and health care workers is still currently low, the long-term consequences of continued, uncontrolled transmissions presents a high risk to all populations.”
California has recently seen a significant rise in detections of H5N1 in dairy herds. Experts believe that animals at as many as half the dairy farms in the state are infected. That is why it is important to pasteurize milk, which kills the virus. (All milk sold across state lines is pasteurized; 30 states allow the in-state sale of nonpasteurized milk, which is labeled “raw.”) Two states, Colorado and Pennsylvania, have agreed to test pooled milk from all farms before pasteurization to monitor spread. Bulk milk testing should be mandatory in all states with dairy farms to determine the full extent of the infection on these farms and to allow us to contain the virus. As if to underline the importance of such a mandate, bird flu was detected in raw milk bought retail last Thursday from a dairy producer based in Fresno, Calif.
Without mandatory testing, bird flu will continue circulating at farms across the country, which substantially increases the risk that the virus mutates and evolves to allow a human-to-human transmission that will be hard to stop.
H5N1 has already shown a propensity to rapidly infect hundreds of herds and farms in the United States. Since March, 616 dairy herds in 15 states have been infected with H5N1. And since the onset of the outbreak in February 2022, H5N1 has been detected in poultry in 49 states, affecting a total of 111 million birds.
There has also been an increase in H5N1 detections in migratory and commercial birds in the European Union, Canada, Japan and South Korea, compared with 2023.
What’s also worrisome is that our arsenal to fight back might not be up to the task.
An analysis by the Centers for Disease Control and Prevention found that a mutation in people in Washington State who work as poultry cullers might reduce the effectiveness of oseltamivir, also known as Tamiflu, in treating influenza A, a type of flu that includes H5N1 and many other subtypes. And a mutation found in a recent California case could reduce the effectiveness of baloxavir marboxil, another drug used to treat influenza A.
In the case of monoclonal antibodies for use against the virus, there are none commercially available at present. These lab-produced antibodies are designed to mimic the body’s immune response and directly target the virus.
As for vaccines, there has been modest progress on candidates for mRNA vaccines, which stimulate the body’s immune system against a specific virus. The candidates could offer more effective countermeasures in response to worrisome mutations. Importantly, the companies that increased production of the mRNA vaccines during Covid-19 are developing bird flu vaccines.
Fortunately, the country already has five million doses of the influenza A (H5) vaccine on hand, and another five million doses will probably be ready by the end of the year. That is enough to cover the farmworker community. That vaccine is expected to have similar effectiveness to that of our seasonal flu vaccines, from 30 to 70 percent.
No one knows how many mutations will be required to set off human-to-human respiratory spread. That could require many mutations and may never happen. But we could also be just two or three mutations away. If the virus begins to transmit efficiently among humans, it will be very difficult to contain, according to the Johns Hopkins assessment, and “the likelihood of a pandemic is very high.”
The incoming Trump administration needs to be prepared.
More on bird flu
Opinion | Tulio de Oliveira
The World Is Watching the U.S. Deal With Bird Flu, and It’s Scary
Nov. 19, 2024
How U.S. Farms Could Start a Bird Flu Pandemic
Aug. 21, 2024
Opinion | Jennifer B. Nuzzo
How Scared Should You Be of Bird Flu?
June 19, 2024
David A. Kessler, a physician and lawyer, was the commissioner of the Food and Drug Administration during the George H.W. Bush and Clinton administrations and was the Biden administration’s chief science officer during Covid-19. He was also the dean of the medical schools at Yale and the University of California, San Francisco, where he is now a professor.
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