Influenza is on the rise across the country, according to a new Centers for Disease Control and Prevention report. But experts anticipate that the worst of the season is not yet upon us.
Officials at the CDC said physician encounters for flu-like symptoms – which are closely correlated to actual flu diagnoses – have risen sharply from last week. The fevers, coughs and sore throats for which the infection is known are now especially high in 10 states: Alabama, Arizona, Arkansas, Kentucky, Louisiana, Mississippi, Nevada, Oklahoma, South Carolina and Texas.
“Influenza seems to be extraordinarily widespread in the United States,” said Dr. William Schaffner, an infectious disease and public health expert at Vanderbilt University in Tennessee.
“This is a little bit unusual for flu,” he added. “It usually starts in one place of the country and spreads to the rest. There is no part of the United States that has not been touched by the flu.”
The new report also shows that the spike in flu-like symptoms has been accompanied by a similar increase in lab tests positive for the H3N2 influenza strain.
“The dominant virus is A/H3N2, a generally more severe influenza viral strain,” Schaffner said. “It tends to cause more severe disease, and risk of death is higher particularly in older persons.”
Worse, this season’s vaccine was only 10 percent effective against the H3N2 strain in Australia – a foreboding sign for the northern hemisphere. Influenza researchers have blamed this decreased effectiveness on the most common process of vaccine manufacturing, which uses chicken eggs. Viruses are unpredictable, and if they are raised in eggs for vaccine production, their structure may not perfectly match those found in our environment.
Despite this possible shortcoming, Schaffner said it still makes sense to get the shot if you have not already.
“Even though there are questions about the effectiveness against the dominant strain, it continues to be effective against the other strains,” he said, noting that the measure of effectiveness does not take partial protection into account. “A lot of the people who were vaccinated did not have to be hospitalized or develop severe disease, and they didn’t die.”
Another benefit of vaccination? You won’t be part of the problem.
“It also makes it less likely that we are going to spread the virus – no one wants to be the dreaded spreader,” Schaffner said. “It’s not too late to get vaccinated, but RUN, don’t linger, to get vaccinated.”
Although the CDC is not yet calling this sudden rise in numbers an epidemic, science may tell us what is coming based on past trends.
“We have very cloudy crystal balls when it comes to influenza because influenza is fickle,” Schaffner said. “The flu started a bit early this year and is now going up very dramatically.”
He added: “It looks like we’ll have a big season that peaks a bit early, like January or February, but we’ll just have to see. Flu will do what it wants.”