What Can the United States Learn from Australia's 2019 Flu Season?
H3N2, a particularly virulent strain of influenza, blew through Australia. Is it coming to the United States this fall and winter?
Australia’s influenza season started 2 months earlier and peaked sooner compared to years past, leading health care experts to believe the United States could face an equally tough season.
As of August, 12.5 million flu vaccines were distributed throughout Australia. The death toll down under reached 430, but officials still believe it could rise. That’s more than usual, according to the New York Times. Their reporting concluded 662 individuals died this year from the flu, compared to 745 in 2017, though mortality rates are calculated differently in Australia.
In 2017, Australia had its worst-ever flu outbreak since monitoring and tracking techniques were put in place. Subsequently, one of the worst modern US flu seasons followed, during which an estimated 79,000 people died.
Australia isn’t always indicative of what the flu season may be like in the US, the New York Times report added. Either way, though, “the best move is to get the vaccine right now,” Daniel B. Jernigan, director of the influenza division of the US Centers for Disease Control and Prevention, told the Times.
H3N2 was the predominant strain in the Southern Hemisphere for 2019—a strain that is known for more severe illness, especially among vulnerable populations such as the elderly. But Jernigan said that doesn’t necessarily mean that H3N2 will come to the United States. Strains appear in various countries, he said, including New Zealand, Chile, and South Africa.
That said, the World Health Organization’s consultation for flu vaccines recommended that H3N2 virus be added to the inoculation for the 2019-20 seasonal wave.
Those who get the flu vaccine should expect to be protected for about 6 months, according to an NBC News report. It takes about 2 weeks to build immunity following vaccination in an otherwise healthy individual.
Influenza vaccination was also recently associated with a reduced risk of death from all-causes, cardiovascular causes, acute myocardial infarction, and stroke in hypertensive patients, suggesting the vaccination may have a protective effect against more than just the flu.
While a flu season in the United States typically begins in October and November with a peak in February, last year’s flu season ran from October 1 through May 4. The flu season may have already arrived in the United States, as a 4-year-old with underlying health issues passed away from illness after contracting the flu in California in September.
The CDC maintains that “all persons aged 6 months and older who do not have contraindications get vaccinated, but vaccination is especially important for persons at high risk for serious influenza-associated complications, including persons aged ≥65 years, children aged <5 years, pregnant women, and persons with certain underlying medical conditions.”
A recent Morbidity and Mortality Weekly Report regarding flu activity suggested that it is too early in the season to know which viruses will circulate in the US this fall. During the summer months, from May to September 2019, outpatient visits to health care providers for flu-like symptoms was below the national baseline. H3N2 was the predominant strain in most regions during the off season, the CDC said.
For this fall and winter, officials with the CDC said, they are still unsure how severe the season might be, but “regardless of what is circulating, the best protection against influenza is an influenza vaccine.” And the sooner, the better.