U.S. health officials said they are concerned the upcoming flu season could be a bad one, based on reports from the Southern Hemisphere, where the flu season recently ended for the year.
In Australia, for example, there were record-high numbers of laboratory-confirmed flu cases this year — more than 2.5 times the number last year, according to the Australian Government Department of Health. And flu hospitalizations and deaths in Australia were also higher than average this past season.
That does not bode well for the United States, experts say.
"As clinicians in the United States prepare for the start of another influenza season, experts have been watching the Southern Hemisphere winter for hints of what might be in store for us in the north," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and colleagues wrote in a recent paper published in The New England Journal of Medicine. "Reports from Australia have caused mounting concern" about the upcoming flu season, the authors wrote. [6 Myths About the Flu Vaccine]
Australia's bad flu season may have been due, in part, to a mismatch between the flu strains included in this year's flu vaccine and the flu strains that were circulating in the public. According to preliminary estimates from Australia, the flu vaccine was 33 percent effective at preventing the flu and only 10 percent effective at preventing infection with H3N2, the predominate flu strain in circulation during the country's flu season.
The U.S. will use the same flu vaccine this year as the one used in Australia, and early data show that H3N2 is also the predominate flu strain in circulation in the United States so far this season, according to the Centers for Disease Control and Prevention.
Still, there's no way to predict for certain how severe or mild the flu season will be in any given year. So, health officials still recommend that everyone ages 6 months and older get a flu shot this season.
"However imperfect, though, current influenza vaccines remain a valuable public health tool, and it is always better to get vaccinated than not to get vaccinated," the paper said.
The paper also noted that the flu vaccine "mismatch" seen in Australia this year could be related to the way most flu vaccines are currently made: using chicken eggs to "grow" the flu virus strains. During this egg-based production process, flu strains may acquire changes that facilitate their replication in eggs but that reduce their effectiveness at preventing flu, the paper said.
The possibility of a low-effectiveness flu vaccine this year "underscores the need to strive toward a 'universal' influenza vaccine that will protect against seasonal influenza drift variants, as well as potential pandemic strains, with better durability than current annual vaccines," the officials said in their paper. "In all likelihood, such a vaccine would not be subject to the limitations of egg-based vaccine technology," the authors said.
Original article on Live Science.