A Decade After the 2009 H1N1 Pandemic: Where Are We Now?

It’s been 10 years since the beginning of the worldwide (H1N1)pdm09 influenza virus pandemic, and while preparedness to detect and respond to influenza pandemics has improved in the decade since, it remains 1 of the greatest public health challenges of our time.

According to estimates from the US Centers for Disease Control and Prevention (CDC), the United States saw 60.8 million cases, 274,304 hospitalizations, and 12,469 deaths due to H1N1 virus between April 12, 2009 to April 10, 2010. Worldwide, the virus caused an estimated 151,700-575,400 deaths. In an interview with Contagion^®, William Schaffner, MD, past president of the National Foundation for Infectious Diseases pointed out just how hard it is to predict the severity of flu from season to season.

“As we say in the trade, if you’ve seen 1 flu season, you’ve seen 1 flu season,” joked Schaffner about the mutable virus. “Almost at any time could we have a major new influenza pandemic with a new virus such as 2009.”

We are somewhat more prepared now than we were 10 years ago for pandemic influenza, says Schaffner, thanks to substantial advances including more precise diagnostic tests and an increase in the number of laboratories testing influenza viruses for resistance to antivirals. On the clinical side, though, there will always be finite resources such as hospital beds, respirators, and trained personnel to handle a surge in patient evaluation and treatment needs, both outpatient and inpatient. “What we have done is reevaluated our emergency pandemic preparedness plan, so we can adjust the finite resources we have and redirect many of them to pandemic should the need arise,” said Schaffner, though a bad flu season can still quickly strain the United States health care system.

“On the preventive side we’ve made what I would call baby steps, and here science is the block,” said Schaffner, noting the last decade has seen ample flu vaccine research leading to the availability of high-dose vaccine, adjuvanted vaccine, recombinant vaccine, and cell-based vaccines which can be produced more rapidly in response to a new pandemic flu. And while still years away from being on the market, researchers continue to work towards developing a universal flu vaccine that could offer protection across multiple flu seasons as well as new methods for administering the flu vaccine, such as an ingestible capsule or a microneedle skin patch.

“If we had those we could entirely reconfigure how we deliver influenza vaccine to large segments of the population much more quickly,” said Schaffer. “Those research efforts have not yet culminated in practical products but over these 10 years we’ve gotten much closer.”

As a consequence of the 2009 H1N1 pandemic, the World Health Organization’s Global Influenza Surveillance and Response System is now much more robust and better integrated, growing by more than 26% since 2014. With most new influenza virus strains emerging from Southeast Asia, Schaffner says that the surveillance system is constantly looking at the circulating influenza viruses in the Northern and Southern Hemispheres. It now has the capacity to quickly sequence influenza virus genomes and share that information in real time.

“That whole alert system is much more efficient and comprehensive than it was a decade ago,” giving the health care system more time to prepare for emerging pandemic viruses, said Schaffner. “The antiviral drug manufacturers would have more time to gear up their production, and we would have more time to create a vaccine.”