Herd Immunity: Public Health and H5N1

When the U.S. Department of Agriculture announced in late March that dairy cattle in three states had been sickened by H5N1 — a virulent and often deadly disease known scientifically as highly pathogenic avian influenza and colloquially as “bird flu” — alarm bells began ringing for COVID-weary public health professionals and policy experts across the nation.

Among them: Rob DeLeo, an associate professor of public policy and affiliate of Bentley’s Center for Health and Business who specializes in the political and social dimensions of preparedness policymaking. The outbreaks elicited immediate and widespread concern, he explains, because they “represent the first time dairy cows in the United States have served as hosts for H5N1” and therefore increase the risk of the virus mutating and becoming easily transmissible to other mammals, including livestock, pets and humans. Continued outbreaks throughout the last six months — to date, 319 herds in 14 states have been infected — have further fanned fears, DeLeo says, that H5N1 could be “fueling a possible pandemic.”

DeLeo is no stranger to public health threats, having spent the last four years leading teams in a series of federally funded research projects investigating and informing America’s response to COVID-19. Now, he brings his expertise to bear on H5N1: Supported by a $200,000 grant from the National Science Foundation (NSF), DeLeo and colleagues from Mississippi State University and Montana State University recently embarked on a study to explore and assess risk mitigation and messaging strategies employed by federal, local and state governments and health care professionals as the H5N1 outbreaks unfold. 

Right now, officials say the threat to human health is minimal, as there are no confirmed cases of human-to-human H5N1 transmission. But DeLeo notes that caution is warranted because of the disease’s high mortality rate: Of the 896 human cases of H5N1 resulting from contact with infected birds and documented between 2003 and 2004, 52% proved fatal. (By contrast, the estimated case fatality rate for COVID-19 is 10%.)

Beyond the risk to people and pets, sustained outbreaks could wreak havoc on America’s $753 billion dairy industry, which accounts for roughly 3.5% of the GDP. “Depending on their risk perceptions of H5N1,” he says, “people may change their dairy consumption behaviors.” Should the virus spread from dairy cattle to beef cattle, the financial impact could be even greater, given that the U.S. is the world’s top producer of beef as well as its largest consumer.

According to DeLeo, the most effective way to mitigate health and economic risks is through clear, concise and coordinated communication among stakeholders. That’s why his new study is specifically designed to assess the alignment (or lack thereof) between risk messaging and behavior within and among three key groups: the federal government, health care providers and the American public. Over the next eight months, DeLeo and his co-researchers will conduct three rounds of interviews with officials from the USDA’s Animal and Plant Health Inspection Service (APHIS), the federal agency responsible for establishing regulations to monitor and mitigate animal and plant diseases. They will also conduct a three-wave panel survey with veterinarians — who are charged with treating sickened animals and implementing APHIS regulations — and U.S. residents.  

DeLeo emphasizes the unique value of the study in that it allows researchers to analyze, in near-real time, how risk communication, perception and behavior evolve in a pre-pandemic context. “Research on human preparation and mitigation response to disasters is typically captured only when there is an immediate threat to human health and well-being,” he explains. “Our study, by contrast, represents a rare opportunity to collect data during the nascent stage of a disease outbreak, when the virus is aggressively circulating among animal populations but prior to human spillover.”  

As the researchers will be interviewing and surveying the same group of respondents during all three phases of the study, they’ll also gain critical insights into how individual risk perception and behavior changes over time. “This approach will enable us to develop a more robust and nuanced perspective on risk communication and response efforts,” DeLeo says, noting that that results from each stage of the project will be shared directly with APHIS, veterinary trade organizations and other public health officials via summaries and technical reports. The team also plans to inform the public of their findings through op-eds in national and regional news outlets.

“The H5N1 outbreak in dairy cattle represents a potential watershed moment for novel influenza mitigation in the U.S.,” DeLeo says. “The individuals managing this crisis — APHIS, state public health officials and veterinarians working on the front lines — need rapid and actionable information about how stakeholders are responding.”  

By providing just that, he and his co-researchers are hopeful they can help public health officials avoid the pitfalls experienced during COVID: “Our team is uniquely positioned to inform operational strategies promptly and effectively,” DeLeo explains, while “helping to mitigate the potential proliferation of false and misleading information that may emerge as this crisis rolls on.”