“Every year we don’t really know until it hits,” said Dr. Steven Lawrence, infectious disease specialist at Washington University. “It’s useful knowing what’s going on in the southern hemisphere. If there’s an emergence of a new strain, if the virus has mutated slightly, it could be a harbinger for the possibility of a bad season here.”
Disease investigators monitor global virus activity throughout the year to help predict the threat of influenza in the next winter. Australia has more than double the number of flu cases this season compared with 2016, and most of those have been an H3N2 strain of the virus that tends to cause more outbreaks and more severe illnesses in older people and those with compromised immune systems.
The flu vaccine available now does carry protection against the H3N2 strain that is circulating in Australia, as well as at least two other strains of the virus. A vaccine that protects against four strains of the virus should be more widely available this year, experts said.
As a general rule, flu season starts around Halloween, peaks at the Super Bowl and is finished by Easter, Lawrence said. Doctors recommend getting the flu shot as soon as possible to build up immunity before the season starts.
There were 71,469 cases of flu recorded in Missouri last season, the most in more than a decade. That was up from 20,100 in the 2015-2016 season, which was close to the five-year average.
Influenza causes respiratory illness with symptoms of fever, cough, muscle aches and fatigue. The virus is spread from person to person through droplets of saliva from sneezing or coughing.
Diligent hand washing and coughing or sneezing into the sleeve can help prevent the spread of the virus, but the best protection is the vaccine. Federal guidelines call for everyone older than 6 months to get the shot. People older than 65, those with chronic conditions and pregnant women are especially vulnerable to severe disease.
All pregnant women should still be vaccinated despite the release Wednesday of a small study out of Wisconsin showing a possible association with miscarriage in women who received the vaccine two years in a row, said the Centers for Disease Control and Prevention, which funded the research. Previous studies have shown no correlation, and data indicate the flu is far more dangerous in pregnancy than any potential risk from the vaccine, according to the CDC.
Flu trackers also are keeping watch on an H7N9 bird flu outbreak in China. Most of the 759 people infected from October through July reported contact with poultry, usually at live bird markets. There were 281 deaths for a mortality rate of 37 percent, according to a new report from the CDC.
So far, the deadly virus strain does not pass easily from chickens to people, or from person to person. But the high mortality rate has scientists on alert.
“The concern has been that as these viruses continuously mutate, if one of those mutations imparts the ability to easily transmit from human to human then we could be in big trouble,” Lawrence said.
Researchers at St. Louis University are set to recruit volunteers for a clinical trial of an H7N9 bird flu vaccine to start in the next couple of months.
If the vaccine trial proves effective, the goal would be to create a national stockpile for any potential outbreaks, said Dr. Sharon Frey of SLU’s Center for Vaccine Development.
While the risk of a bird flu outbreak remains theoretical, doctors said their real concern was the seasonal flu that infects thousands every year.
“It’s not a disease that people should take lightly,” Frey said. “It has a huge burden on society. My plea is always to encourage people to get vaccinated.”