With avian flu, it's time to prepare, not panic - The Boston Globe

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So why is this cattle outbreak a big deal? Over the past two years, an increasing number of mammalian species have been reported to have contracted the virus, and, for the first time, it appears to be spreading from mammal to mammal in a sustained fashion. Since humans are mammals, that phenomenon warrants close attention. Affected species have included seals, farmed mink, goats, and cats. But the new outbreak in dairy cows is particularly concerning for public health, for several reasons.

Lactating cows are housed in very close proximity and are frequently moved from farm to farm and across state lines, increasing the risk of spread within and between herds and to new locales. And farms that have dairy cows frequently have other animals in close proximity to them, such as cats (which interact closely with farmers), chickens (which are highly susceptible to avian influenza infection and contribute eggs and meat to the food chain), goats, and pigs. It is especially important to prevent avian influenza infection in pigs because pigs are believed to have the potential to serve as "mixing vessels" for influenza viruses. In theory, if infected with avian and mammalian flu at the same time, flu genes could reassort inside the pig and create a highly pathogenic strain adapted for mammalian transmission.

Additionally, some farm workers are undocumented and/or uninsured, may have limited access to health care, and may, for a variety of reasons, be reluctant to seek testing when symptomatic. Lastly, there is a potentially significant impact on the food supply from a decrease in the distribution of milk (which, in the United States, is found in a shockingly large proportion of foods), and if beef cattle, other food animals, and even more chickens become infected, it's not hard to imagine a scenario where our food industry suffers considerable shortages with resulting economic consequences.

I was reassured by what I heard during an April 25 symposium I participated in with the Centers for Disease Control and Prevention, the Food and Drug Administration, the National Institutes of Health, and the Administration for Strategic Preparedness and Response. Together, we're coordinating information and deciding what more needs to be done to prepare in case avian flu mutates and is able to be transmitted human to human.

The CDC is tracking emergency room visits and positive test results for the current avian flu in order to detect an early signal if people start to get sick. While some are calling for wastewater surveillance of H5N1, it's not clear how useful that would be (most farms are not tied into sewers and wastewater is full of runoff that includes wild bird feces — we already know wild birds carry the virus). Two candidate vaccines already in hand show likely efficacy against the virus, and planning is underway to scale up production and deployment if needed.

Discussions have begun about commercializing tests for H5N1. One of the most pressing but difficult needs is to reduce the inherent yet understandable conflict of interest that results from the fact that the USDA is charged with managing the cattle outbreak investigation and also, according to its own mission statement, with keeping "America's farmers and ranchers in business." To gain cooperation from farmers to test cows and farm workers, compensation for lost business will be necessary. The CDC and WHO have declared the risk to the general population low. I agree.

Last week, the FDA announced that 1 in 5 commercial dairy products surveyed (that had already reached the retail shelf) tested positive for the presence of the virus. That means the outbreak is a lot bigger than we know and that milk products from infected cows are making it into the food supply. And yet, surveillance shows no increases in human influenza cases across the country. In fact, those numbers are still falling, consistent with the expected springtime drop in respiratory viruses. That likely means — and this is not at all surprising — that pasteurization is working as it should to kill all traces of this virus in milk. Genetic analyses of the virus circulating among cows show that it has not mutated to be more likely to infect humans and that it remains susceptible to currently available antiviral drugs. That is all very good news.

Is this my biggest public health concern of the day? At this point, given the numbers, we are far more likely to see cases of measles, which is also orders of magnitude more contagious. Measles cases are far too common in the United States today due to declining vaccination rates in children.

The avian flu outbreak could peter out just as easily (or perhaps more so) as it could evolve further. One thing is clear: With this and future public health incidents, officials should learn from the communication mistakes made throughout the COVID-19 pandemic — focus on transparency and honesty while avoiding overly sensational statements that induce panic — and avoid panic-driven decision-making.

Dr. Shira Doron is an infectious disease physician and Chief Infection Control Officer at Tufts Medicine and a professor of medicine at Tufts University School of Medicine. She sits on the Infectious Diseases Society of America's Practice & Quality Committee.