DR. JENNIFER NUZZO: H5N1 isn’t easily infecting human YET – but NEXT pandemic may few mutations away

Dr. Jennifer Nuzzo He is a professor of epidemiology and director of the Pandemic Center at the Brown University School of Public Health.

Tens of thousands of birds die suddenly on the Peruvian coast and throughout the American continent.

Then hundreds of sea lions turn up dead. And tragically, an 11-year-old girl in Cambodia loses her life.

What is the cause of all these recent unusual events?

A highly pathogenic virus known as H5N1 – avian influenza.

Fortunately, H5N1 is not yet capable of spreading from person to person like the flu viruses we are used to dealing with in North America during the fall and winter.

Although the operable word is ‘yet’.

Waterfowl are natural carriers of these dangerous viral strains. And most of the time, they do not pose a threat to humans, unless there is direct contact with infected animals or their waste.

Avian influenza viruses do not readily bind to human respiratory cells. Therefore, the disease is not easily transmitted from person to person through coughing, sneezing, or breath droplets.

But the growing ability of H5N1 to spread between animals and directly infect people is stoking fears that the world may be just a few genetic mutations away from another pandemic.

And there are good reasons to worry.

Since 2022, in the United States alone, a record 58 million farmed birds, such as chickens and turkeys, have been killed or euthanized after exposure to the virus.

The virus also jumped to red foxes, mink, raccoons, skunks, and other non-human mammals in the Northwest, Midwest, and Northeast.

In fact, various forms of H5N1 have been spreading in wildlife populations for more than 20 years, and they are nasty.

H5N1 has wiped out entire flocks and devastated wildlife populations. Hundreds of people have fallen ill since the virus was first identified in 1997. And among those known to have contracted the virus, about half have died.

That makes H5N1 much more deadly than COVID-19.

What we don’t know is how deadly the virus would be if it had the ability to easily infect and transmit between humans.

Every time a virus invades a cell, it makes copies of itself. Sometimes in the process you make a mistake: a mutation. The mutations may not cause any change in the way the virus can infect or make you sick. But as we’ve seen with the Delta and Omicron variants of the virus that causes COVID-19, sometimes these mutations can make the virus more transmissible.

And we know enough to want to act quickly to prevent that from happening.

H5N1 is not the first zoonotic virus, a pathogen that originates in wildlife and spreads to human populations, that poses a serious threat.

The human immunodeficiency virus, or HIV, which has killed more than 40 million people and continues to rise, first emerged in the wild. The virus likely infected human populations multiple times before acquiring the ability to spread and move around the world.

Since the advent of HIV, there have been many more animal viruses that have acquired the ability to infect humans.

In the last twenty years, the list of zoonotic disease outbreaks that have occurred is staggering. The list includes Ebola, West Nile virus, Mpox, pandemic influenza in 2009, and two novel coronaviruses that predate the current COVID-19 pandemic.

Zoonotic diseases are believed to kill more than 2.7 million people worldwide each year.

That is awesome.

And if that’s not worrying enough, we probably won’t be ready for the next one.

The steady pace of these events tells us that the accelerated emergence of new zoonotic diseases is the new normal.

Since the 1940s and 1950s, when HIV may have first jumped from chimpanzees to humans, the frequency of zoonotic disease outbreaks has been steadily increasing.

At the end of the 20th century, the number of outbreaks of new infectious diseases was more than five times higher than in the 1940s; not all are zoonotic, but most are.

And surprisingly, more than two-thirds of all human outbreaks of new diseases have been caused by zoonotic pathogens.

There are many possible reasons for this.

In North America and around the world, human use of land is constantly expanding. We are putting new pressures on wildlife populations, increasing their likelihood of getting sick and infected with new diseases. Climate change is altering natural environments and adding to the stress.

The animals themselves are migrating to new regions, creating new opportunities for them to come into contact with people and thus spread new viruses. And repeated exposure to humans creates more opportunities for diseases to mutate.

While all viruses are different, it would be foolish to ignore that the conditions that may have led to the HIV epidemic are magnified today.

If these viruses become easily transmissible between humans, our modern behavior helps their spread. We are more mobile than ever: you can reach any destination on the planet in 48 hours.

Finally, as bad as H5N1 avian influenza is, it may not be the worst zoonotic disease threat we could face.

The United States has been preparing for a possible H5N1 pandemic for about 20 years. It has laboratories that can detect avian influenza and has stockpiled millions of doses of H5N1 vaccine.

Thanks to a market for seasonal influenza vaccines, a global infrastructure already exists to manufacture vaccines for new influenza viruses. The United States even has a secret supply of eggs to produce new flu vaccines, if needed.

But as COVID-19 has shown us, when an entirely new virus emerges and spreads, it is much more difficult to respond to it. If a new zoonotic disease emerges, we would not have immediate access to the same tools we now use to fight influenza or COVID-19.

With no vaccines or medicines to prevent or treat infection, we are left with face masks and social distancing to contain the spread.

We need new tools and strategies to protect ourselves from contagious zoonotic pathogens that don’t just depend on our willingness to lock down society and lock ourselves inside our homes. Forcing businesses and schools to close represents a lack of preparation.

We cannot allow zoonotic diseases like H5N1 to spread unchecked or they could mutate and become a greater threat to humans.

The Biden Administration is right to consider vaccinating US poultry against H5N1, but it is not enough.

That may protect US agricultural interests, but it won’t stop the virus from infecting wildlife or mutating to more easily infect humans.

We need to do more.

Ensuring that our schools and businesses are well ventilated will not only reduce our vulnerability to future zoonotic threats, but will also protect us from other viruses, such as seasonal influenza.

We shouldn’t wait until our worst-case scenario comes true to boost research and development for new vaccines, rapid tests, and drugs.

The World Health Organization recently urged governments to invest in the development of prototype vaccines for each strain of animal influenza, so that they can be tested and manufactured more quickly.

We need better surveillance of emerging viruses in wildlife and people who are at high risk of exposure to animals.

After three years of responding to COVID-19, the public and, more importantly, politicians may be reluctant to do whatever it takes to prevent a new virus from changing our lives.

Funding for the response to COVID-19 has expired. Millions of healthcare workers have left their jobs, leaving our fragmented and weakened pandemic healthcare entities even more depleted. Efforts to develop new and improved vaccines for COVID-19 are stalling.

None of this bodes well for our preparation for the next pandemic.

We don’t know when it might happen or what disease it will be, but we have every reason to believe that this is a zoonotic disease, and possibly one we haven’t seen before.